From a5f4374a9610fd7286c2164d4e680436727eff71 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 22 Feb 2012 11:01:49 +0100 Subject: uprobes: Move to kernel/events/ Consolidate the uprobes code under kernel/events/, where the various core kernel event handling routines live. Acked-by: Peter Zijlstra Cc: Srikar Dronamraju Cc: Jim Keniston Cc: Oleg Nesterov Cc: Masami Hiramatsu Cc: Arnaldo Carvalho de Melo Cc: Anton Arapov Cc: Ananth N Mavinakayanahalli Link: http://lkml.kernel.org/n/tip-biuyhhwohxgbp2vzbap5yr8o@git.kernel.org Signed-off-by: Ingo Molnar --- kernel/events/Makefile | 3 + kernel/events/uprobes.c | 1011 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 1014 insertions(+) create mode 100644 kernel/events/uprobes.c (limited to 'kernel/events') diff --git a/kernel/events/Makefile b/kernel/events/Makefile index 22d901f..103f5d1 100644 --- a/kernel/events/Makefile +++ b/kernel/events/Makefile @@ -3,4 +3,7 @@ CFLAGS_REMOVE_core.o = -pg endif obj-y := core.o ring_buffer.o callchain.o + obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o +obj-$(CONFIG_UPROBES) += uprobes.o + diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c new file mode 100644 index 0000000..884817f --- /dev/null +++ b/kernel/events/uprobes.c @@ -0,0 +1,1011 @@ +/* + * User-space Probes (UProbes) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) IBM Corporation, 2008-2011 + * Authors: + * Srikar Dronamraju + * Jim Keniston + */ + +#include +#include +#include /* read_mapping_page */ +#include +#include +#include /* anon_vma_prepare */ +#include /* set_pte_at_notify */ +#include /* try_to_free_swap */ + +#include + +static struct rb_root uprobes_tree = RB_ROOT; + +static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */ + +#define UPROBES_HASH_SZ 13 + +/* serialize (un)register */ +static struct mutex uprobes_mutex[UPROBES_HASH_SZ]; + +#define uprobes_hash(v) (&uprobes_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ]) + +/* serialize uprobe->pending_list */ +static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ]; +#define uprobes_mmap_hash(v) (&uprobes_mmap_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ]) + +/* + * uprobe_events allows us to skip the uprobe_mmap if there are no uprobe + * events active at this time. Probably a fine grained per inode count is + * better? + */ +static atomic_t uprobe_events = ATOMIC_INIT(0); + +/* + * Maintain a temporary per vma info that can be used to search if a vma + * has already been handled. This structure is introduced since extending + * vm_area_struct wasnt recommended. + */ +struct vma_info { + struct list_head probe_list; + struct mm_struct *mm; + loff_t vaddr; +}; + +/* + * valid_vma: Verify if the specified vma is an executable vma + * Relax restrictions while unregistering: vm_flags might have + * changed after breakpoint was inserted. + * - is_register: indicates if we are in register context. + * - Return 1 if the specified virtual address is in an + * executable vma. + */ +static bool valid_vma(struct vm_area_struct *vma, bool is_register) +{ + if (!vma->vm_file) + return false; + + if (!is_register) + return true; + + if ((vma->vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)) == (VM_READ|VM_EXEC)) + return true; + + return false; +} + +static loff_t vma_address(struct vm_area_struct *vma, loff_t offset) +{ + loff_t vaddr; + + vaddr = vma->vm_start + offset; + vaddr -= vma->vm_pgoff << PAGE_SHIFT; + + return vaddr; +} + +/** + * __replace_page - replace page in vma by new page. + * based on replace_page in mm/ksm.c + * + * @vma: vma that holds the pte pointing to page + * @page: the cowed page we are replacing by kpage + * @kpage: the modified page we replace page by + * + * Returns 0 on success, -EFAULT on failure. + */ +static int __replace_page(struct vm_area_struct *vma, struct page *page, struct page *kpage) +{ + struct mm_struct *mm = vma->vm_mm; + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *ptep; + spinlock_t *ptl; + unsigned long addr; + int err = -EFAULT; + + addr = page_address_in_vma(page, vma); + if (addr == -EFAULT) + goto out; + + pgd = pgd_offset(mm, addr); + if (!pgd_present(*pgd)) + goto out; + + pud = pud_offset(pgd, addr); + if (!pud_present(*pud)) + goto out; + + pmd = pmd_offset(pud, addr); + if (!pmd_present(*pmd)) + goto out; + + ptep = pte_offset_map_lock(mm, pmd, addr, &ptl); + if (!ptep) + goto out; + + get_page(kpage); + page_add_new_anon_rmap(kpage, vma, addr); + + flush_cache_page(vma, addr, pte_pfn(*ptep)); + ptep_clear_flush(vma, addr, ptep); + set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot)); + + page_remove_rmap(page); + if (!page_mapped(page)) + try_to_free_swap(page); + put_page(page); + pte_unmap_unlock(ptep, ptl); + err = 0; + +out: + return err; +} + +/** + * is_bkpt_insn - check if instruction is breakpoint instruction. + * @insn: instruction to be checked. + * Default implementation of is_bkpt_insn + * Returns true if @insn is a breakpoint instruction. + */ +bool __weak is_bkpt_insn(uprobe_opcode_t *insn) +{ + return *insn == UPROBES_BKPT_INSN; +} + +/* + * NOTE: + * Expect the breakpoint instruction to be the smallest size instruction for + * the architecture. If an arch has variable length instruction and the + * breakpoint instruction is not of the smallest length instruction + * supported by that architecture then we need to modify read_opcode / + * write_opcode accordingly. This would never be a problem for archs that + * have fixed length instructions. + */ + +/* + * write_opcode - write the opcode at a given virtual address. + * @mm: the probed process address space. + * @uprobe: the breakpointing information. + * @vaddr: the virtual address to store the opcode. + * @opcode: opcode to be written at @vaddr. + * + * Called with mm->mmap_sem held (for read and with a reference to + * mm). + * + * For mm @mm, write the opcode at @vaddr. + * Return 0 (success) or a negative errno. + */ +static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe, + unsigned long vaddr, uprobe_opcode_t opcode) +{ + struct page *old_page, *new_page; + struct address_space *mapping; + void *vaddr_old, *vaddr_new; + struct vm_area_struct *vma; + loff_t addr; + int ret; + + /* Read the page with vaddr into memory */ + ret = get_user_pages(NULL, mm, vaddr, 1, 0, 0, &old_page, &vma); + if (ret <= 0) + return ret; + + ret = -EINVAL; + + /* + * We are interested in text pages only. Our pages of interest + * should be mapped for read and execute only. We desist from + * adding probes in write mapped pages since the breakpoints + * might end up in the file copy. + */ + if (!valid_vma(vma, is_bkpt_insn(&opcode))) + goto put_out; + + mapping = uprobe->inode->i_mapping; + if (mapping != vma->vm_file->f_mapping) + goto put_out; + + addr = vma_address(vma, uprobe->offset); + if (vaddr != (unsigned long)addr) + goto put_out; + + ret = -ENOMEM; + new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr); + if (!new_page) + goto put_out; + + __SetPageUptodate(new_page); + + /* + * lock page will serialize against do_wp_page()'s + * PageAnon() handling + */ + lock_page(old_page); + /* copy the page now that we've got it stable */ + vaddr_old = kmap_atomic(old_page); + vaddr_new = kmap_atomic(new_page); + + memcpy(vaddr_new, vaddr_old, PAGE_SIZE); + + /* poke the new insn in, ASSUMES we don't cross page boundary */ + vaddr &= ~PAGE_MASK; + BUG_ON(vaddr + uprobe_opcode_sz > PAGE_SIZE); + memcpy(vaddr_new + vaddr, &opcode, uprobe_opcode_sz); + + kunmap_atomic(vaddr_new); + kunmap_atomic(vaddr_old); + + ret = anon_vma_prepare(vma); + if (ret) + goto unlock_out; + + lock_page(new_page); + ret = __replace_page(vma, old_page, new_page); + unlock_page(new_page); + +unlock_out: + unlock_page(old_page); + page_cache_release(new_page); + +put_out: + put_page(old_page); + + return ret; +} + +/** + * read_opcode - read the opcode at a given virtual address. + * @mm: the probed process address space. + * @vaddr: the virtual address to read the opcode. + * @opcode: location to store the read opcode. + * + * Called with mm->mmap_sem held (for read and with a reference to + * mm. + * + * For mm @mm, read the opcode at @vaddr and store it in @opcode. + * Return 0 (success) or a negative errno. + */ +static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t *opcode) +{ + struct page *page; + void *vaddr_new; + int ret; + + ret = get_user_pages(NULL, mm, vaddr, 1, 0, 0, &page, NULL); + if (ret <= 0) + return ret; + + lock_page(page); + vaddr_new = kmap_atomic(page); + vaddr &= ~PAGE_MASK; + memcpy(opcode, vaddr_new + vaddr, uprobe_opcode_sz); + kunmap_atomic(vaddr_new); + unlock_page(page); + + put_page(page); + + return 0; +} + +static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr) +{ + uprobe_opcode_t opcode; + int result; + + result = read_opcode(mm, vaddr, &opcode); + if (result) + return result; + + if (is_bkpt_insn(&opcode)) + return 1; + + return 0; +} + +/** + * set_bkpt - store breakpoint at a given address. + * @mm: the probed process address space. + * @uprobe: the probepoint information. + * @vaddr: the virtual address to insert the opcode. + * + * For mm @mm, store the breakpoint instruction at @vaddr. + * Return 0 (success) or a negative errno. + */ +int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr) +{ + int result; + + result = is_bkpt_at_addr(mm, vaddr); + if (result == 1) + return -EEXIST; + + if (result) + return result; + + return write_opcode(mm, uprobe, vaddr, UPROBES_BKPT_INSN); +} + +/** + * set_orig_insn - Restore the original instruction. + * @mm: the probed process address space. + * @uprobe: the probepoint information. + * @vaddr: the virtual address to insert the opcode. + * @verify: if true, verify existance of breakpoint instruction. + * + * For mm @mm, restore the original opcode (opcode) at @vaddr. + * Return 0 (success) or a negative errno. + */ +int __weak +set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, bool verify) +{ + if (verify) { + int result; + + result = is_bkpt_at_addr(mm, vaddr); + if (!result) + return -EINVAL; + + if (result != 1) + return result; + } + return write_opcode(mm, uprobe, vaddr, *(uprobe_opcode_t *)uprobe->insn); +} + +static int match_uprobe(struct uprobe *l, struct uprobe *r) +{ + if (l->inode < r->inode) + return -1; + + if (l->inode > r->inode) + return 1; + + if (l->offset < r->offset) + return -1; + + if (l->offset > r->offset) + return 1; + + return 0; +} + +static struct uprobe *__find_uprobe(struct inode *inode, loff_t offset) +{ + struct uprobe u = { .inode = inode, .offset = offset }; + struct rb_node *n = uprobes_tree.rb_node; + struct uprobe *uprobe; + int match; + + while (n) { + uprobe = rb_entry(n, struct uprobe, rb_node); + match = match_uprobe(&u, uprobe); + if (!match) { + atomic_inc(&uprobe->ref); + return uprobe; + } + + if (match < 0) + n = n->rb_left; + else + n = n->rb_right; + } + return NULL; +} + +/* + * Find a uprobe corresponding to a given inode:offset + * Acquires uprobes_treelock + */ +static struct uprobe *find_uprobe(struct inode *inode, loff_t offset) +{ + struct uprobe *uprobe; + unsigned long flags; + + spin_lock_irqsave(&uprobes_treelock, flags); + uprobe = __find_uprobe(inode, offset); + spin_unlock_irqrestore(&uprobes_treelock, flags); + + return uprobe; +} + +static struct uprobe *__insert_uprobe(struct uprobe *uprobe) +{ + struct rb_node **p = &uprobes_tree.rb_node; + struct rb_node *parent = NULL; + struct uprobe *u; + int match; + + while (*p) { + parent = *p; + u = rb_entry(parent, struct uprobe, rb_node); + match = match_uprobe(uprobe, u); + if (!match) { + atomic_inc(&u->ref); + return u; + } + + if (match < 0) + p = &parent->rb_left; + else + p = &parent->rb_right; + + } + + u = NULL; + rb_link_node(&uprobe->rb_node, parent, p); + rb_insert_color(&uprobe->rb_node, &uprobes_tree); + /* get access + creation ref */ + atomic_set(&uprobe->ref, 2); + + return u; +} + +/* + * Acquire uprobes_treelock. + * Matching uprobe already exists in rbtree; + * increment (access refcount) and return the matching uprobe. + * + * No matching uprobe; insert the uprobe in rb_tree; + * get a double refcount (access + creation) and return NULL. + */ +static struct uprobe *insert_uprobe(struct uprobe *uprobe) +{ + unsigned long flags; + struct uprobe *u; + + spin_lock_irqsave(&uprobes_treelock, flags); + u = __insert_uprobe(uprobe); + spin_unlock_irqrestore(&uprobes_treelock, flags); + + return u; +} + +static void put_uprobe(struct uprobe *uprobe) +{ + if (atomic_dec_and_test(&uprobe->ref)) + kfree(uprobe); +} + +static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset) +{ + struct uprobe *uprobe, *cur_uprobe; + + uprobe = kzalloc(sizeof(struct uprobe), GFP_KERNEL); + if (!uprobe) + return NULL; + + uprobe->inode = igrab(inode); + uprobe->offset = offset; + init_rwsem(&uprobe->consumer_rwsem); + INIT_LIST_HEAD(&uprobe->pending_list); + + /* add to uprobes_tree, sorted on inode:offset */ + cur_uprobe = insert_uprobe(uprobe); + + /* a uprobe exists for this inode:offset combination */ + if (cur_uprobe) { + kfree(uprobe); + uprobe = cur_uprobe; + iput(inode); + } else { + atomic_inc(&uprobe_events); + } + + return uprobe; +} + +/* Returns the previous consumer */ +static struct uprobe_consumer * +consumer_add(struct uprobe *uprobe, struct uprobe_consumer *consumer) +{ + down_write(&uprobe->consumer_rwsem); + consumer->next = uprobe->consumers; + uprobe->consumers = consumer; + up_write(&uprobe->consumer_rwsem); + + return consumer->next; +} + +/* + * For uprobe @uprobe, delete the consumer @consumer. + * Return true if the @consumer is deleted successfully + * or return false. + */ +static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *consumer) +{ + struct uprobe_consumer **con; + bool ret = false; + + down_write(&uprobe->consumer_rwsem); + for (con = &uprobe->consumers; *con; con = &(*con)->next) { + if (*con == consumer) { + *con = consumer->next; + ret = true; + break; + } + } + up_write(&uprobe->consumer_rwsem); + + return ret; +} + +static int __copy_insn(struct address_space *mapping, + struct vm_area_struct *vma, char *insn, + unsigned long nbytes, unsigned long offset) +{ + struct file *filp = vma->vm_file; + struct page *page; + void *vaddr; + unsigned long off1; + unsigned long idx; + + if (!filp) + return -EINVAL; + + idx = (unsigned long)(offset >> PAGE_CACHE_SHIFT); + off1 = offset &= ~PAGE_MASK; + + /* + * Ensure that the page that has the original instruction is + * populated and in page-cache. + */ + page = read_mapping_page(mapping, idx, filp); + if (IS_ERR(page)) + return PTR_ERR(page); + + vaddr = kmap_atomic(page); + memcpy(insn, vaddr + off1, nbytes); + kunmap_atomic(vaddr); + page_cache_release(page); + + return 0; +} + +static int copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr) +{ + struct address_space *mapping; + unsigned long nbytes; + int bytes; + + addr &= ~PAGE_MASK; + nbytes = PAGE_SIZE - addr; + mapping = uprobe->inode->i_mapping; + + /* Instruction at end of binary; copy only available bytes */ + if (uprobe->offset + MAX_UINSN_BYTES > uprobe->inode->i_size) + bytes = uprobe->inode->i_size - uprobe->offset; + else + bytes = MAX_UINSN_BYTES; + + /* Instruction at the page-boundary; copy bytes in second page */ + if (nbytes < bytes) { + if (__copy_insn(mapping, vma, uprobe->insn + nbytes, + bytes - nbytes, uprobe->offset + nbytes)) + return -ENOMEM; + + bytes = nbytes; + } + return __copy_insn(mapping, vma, uprobe->insn, bytes, uprobe->offset); +} + +static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, + struct vm_area_struct *vma, loff_t vaddr) +{ + unsigned long addr; + int ret; + + /* + * If probe is being deleted, unregister thread could be done with + * the vma-rmap-walk through. Adding a probe now can be fatal since + * nobody will be able to cleanup. Also we could be from fork or + * mremap path, where the probe might have already been inserted. + * Hence behave as if probe already existed. + */ + if (!uprobe->consumers) + return -EEXIST; + + addr = (unsigned long)vaddr; + + if (!(uprobe->flags & UPROBES_COPY_INSN)) { + ret = copy_insn(uprobe, vma, addr); + if (ret) + return ret; + + if (is_bkpt_insn((uprobe_opcode_t *)uprobe->insn)) + return -EEXIST; + + ret = arch_uprobes_analyze_insn(mm, uprobe); + if (ret) + return ret; + + uprobe->flags |= UPROBES_COPY_INSN; + } + ret = set_bkpt(mm, uprobe, addr); + + return ret; +} + +static void remove_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, loff_t vaddr) +{ + set_orig_insn(mm, uprobe, (unsigned long)vaddr, true); +} + +static void delete_uprobe(struct uprobe *uprobe) +{ + unsigned long flags; + + spin_lock_irqsave(&uprobes_treelock, flags); + rb_erase(&uprobe->rb_node, &uprobes_tree); + spin_unlock_irqrestore(&uprobes_treelock, flags); + iput(uprobe->inode); + put_uprobe(uprobe); + atomic_dec(&uprobe_events); +} + +static struct vma_info *__find_next_vma_info(struct list_head *head, + loff_t offset, struct address_space *mapping, + struct vma_info *vi, bool is_register) +{ + struct prio_tree_iter iter; + struct vm_area_struct *vma; + struct vma_info *tmpvi; + unsigned long pgoff; + int existing_vma; + loff_t vaddr; + + pgoff = offset >> PAGE_SHIFT; + + vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { + if (!valid_vma(vma, is_register)) + continue; + + existing_vma = 0; + vaddr = vma_address(vma, offset); + + list_for_each_entry(tmpvi, head, probe_list) { + if (tmpvi->mm == vma->vm_mm && tmpvi->vaddr == vaddr) { + existing_vma = 1; + break; + } + } + + /* + * Another vma needs a probe to be installed. However skip + * installing the probe if the vma is about to be unlinked. + */ + if (!existing_vma && atomic_inc_not_zero(&vma->vm_mm->mm_users)) { + vi->mm = vma->vm_mm; + vi->vaddr = vaddr; + list_add(&vi->probe_list, head); + + return vi; + } + } + + return NULL; +} + +/* + * Iterate in the rmap prio tree and find a vma where a probe has not + * yet been inserted. + */ +static struct vma_info * +find_next_vma_info(struct list_head *head, loff_t offset, struct address_space *mapping, + bool is_register) +{ + struct vma_info *vi, *retvi; + + vi = kzalloc(sizeof(struct vma_info), GFP_KERNEL); + if (!vi) + return ERR_PTR(-ENOMEM); + + mutex_lock(&mapping->i_mmap_mutex); + retvi = __find_next_vma_info(head, offset, mapping, vi, is_register); + mutex_unlock(&mapping->i_mmap_mutex); + + if (!retvi) + kfree(vi); + + return retvi; +} + +static int register_for_each_vma(struct uprobe *uprobe, bool is_register) +{ + struct list_head try_list; + struct vm_area_struct *vma; + struct address_space *mapping; + struct vma_info *vi, *tmpvi; + struct mm_struct *mm; + loff_t vaddr; + int ret; + + mapping = uprobe->inode->i_mapping; + INIT_LIST_HEAD(&try_list); + + ret = 0; + + for (;;) { + vi = find_next_vma_info(&try_list, uprobe->offset, mapping, is_register); + if (!vi) + break; + + if (IS_ERR(vi)) { + ret = PTR_ERR(vi); + break; + } + + mm = vi->mm; + down_read(&mm->mmap_sem); + vma = find_vma(mm, (unsigned long)vi->vaddr); + if (!vma || !valid_vma(vma, is_register)) { + list_del(&vi->probe_list); + kfree(vi); + up_read(&mm->mmap_sem); + mmput(mm); + continue; + } + vaddr = vma_address(vma, uprobe->offset); + if (vma->vm_file->f_mapping->host != uprobe->inode || + vaddr != vi->vaddr) { + list_del(&vi->probe_list); + kfree(vi); + up_read(&mm->mmap_sem); + mmput(mm); + continue; + } + + if (is_register) + ret = install_breakpoint(mm, uprobe, vma, vi->vaddr); + else + remove_breakpoint(mm, uprobe, vi->vaddr); + + up_read(&mm->mmap_sem); + mmput(mm); + if (is_register) { + if (ret && ret == -EEXIST) + ret = 0; + if (ret) + break; + } + } + + list_for_each_entry_safe(vi, tmpvi, &try_list, probe_list) { + list_del(&vi->probe_list); + kfree(vi); + } + + return ret; +} + +static int __uprobe_register(struct uprobe *uprobe) +{ + return register_for_each_vma(uprobe, true); +} + +static void __uprobe_unregister(struct uprobe *uprobe) +{ + if (!register_for_each_vma(uprobe, false)) + delete_uprobe(uprobe); + + /* TODO : cant unregister? schedule a worker thread */ +} + +/* + * uprobe_register - register a probe + * @inode: the file in which the probe has to be placed. + * @offset: offset from the start of the file. + * @consumer: information on howto handle the probe.. + * + * Apart from the access refcount, uprobe_register() takes a creation + * refcount (thro alloc_uprobe) if and only if this @uprobe is getting + * inserted into the rbtree (i.e first consumer for a @inode:@offset + * tuple). Creation refcount stops uprobe_unregister from freeing the + * @uprobe even before the register operation is complete. Creation + * refcount is released when the last @consumer for the @uprobe + * unregisters. + * + * Return errno if it cannot successully install probes + * else return 0 (success) + */ +int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer) +{ + struct uprobe *uprobe; + int ret; + + if (!inode || !consumer || consumer->next) + return -EINVAL; + + if (offset > i_size_read(inode)) + return -EINVAL; + + ret = 0; + mutex_lock(uprobes_hash(inode)); + uprobe = alloc_uprobe(inode, offset); + + if (uprobe && !consumer_add(uprobe, consumer)) { + ret = __uprobe_register(uprobe); + if (ret) { + uprobe->consumers = NULL; + __uprobe_unregister(uprobe); + } else { + uprobe->flags |= UPROBES_RUN_HANDLER; + } + } + + mutex_unlock(uprobes_hash(inode)); + put_uprobe(uprobe); + + return ret; +} + +/* + * uprobe_unregister - unregister a already registered probe. + * @inode: the file in which the probe has to be removed. + * @offset: offset from the start of the file. + * @consumer: identify which probe if multiple probes are colocated. + */ +void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer) +{ + struct uprobe *uprobe; + + if (!inode || !consumer) + return; + + uprobe = find_uprobe(inode, offset); + if (!uprobe) + return; + + mutex_lock(uprobes_hash(inode)); + + if (consumer_del(uprobe, consumer)) { + if (!uprobe->consumers) { + __uprobe_unregister(uprobe); + uprobe->flags &= ~UPROBES_RUN_HANDLER; + } + } + + mutex_unlock(uprobes_hash(inode)); + if (uprobe) + put_uprobe(uprobe); +} + +/* + * Of all the nodes that correspond to the given inode, return the node + * with the least offset. + */ +static struct rb_node *find_least_offset_node(struct inode *inode) +{ + struct uprobe u = { .inode = inode, .offset = 0}; + struct rb_node *n = uprobes_tree.rb_node; + struct rb_node *close_node = NULL; + struct uprobe *uprobe; + int match; + + while (n) { + uprobe = rb_entry(n, struct uprobe, rb_node); + match = match_uprobe(&u, uprobe); + + if (uprobe->inode == inode) + close_node = n; + + if (!match) + return close_node; + + if (match < 0) + n = n->rb_left; + else + n = n->rb_right; + } + + return close_node; +} + +/* + * For a given inode, build a list of probes that need to be inserted. + */ +static void build_probe_list(struct inode *inode, struct list_head *head) +{ + struct uprobe *uprobe; + unsigned long flags; + struct rb_node *n; + + spin_lock_irqsave(&uprobes_treelock, flags); + + n = find_least_offset_node(inode); + + for (; n; n = rb_next(n)) { + uprobe = rb_entry(n, struct uprobe, rb_node); + if (uprobe->inode != inode) + break; + + list_add(&uprobe->pending_list, head); + atomic_inc(&uprobe->ref); + } + + spin_unlock_irqrestore(&uprobes_treelock, flags); +} + +/* + * Called from mmap_region. + * called with mm->mmap_sem acquired. + * + * Return -ve no if we fail to insert probes and we cannot + * bail-out. + * Return 0 otherwise. i.e: + * + * - successful insertion of probes + * - (or) no possible probes to be inserted. + * - (or) insertion of probes failed but we can bail-out. + */ +int uprobe_mmap(struct vm_area_struct *vma) +{ + struct list_head tmp_list; + struct uprobe *uprobe, *u; + struct inode *inode; + int ret; + + if (!atomic_read(&uprobe_events) || !valid_vma(vma, true)) + return 0; + + inode = vma->vm_file->f_mapping->host; + if (!inode) + return 0; + + INIT_LIST_HEAD(&tmp_list); + mutex_lock(uprobes_mmap_hash(inode)); + build_probe_list(inode, &tmp_list); + + ret = 0; + + list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) { + loff_t vaddr; + + list_del(&uprobe->pending_list); + if (!ret) { + vaddr = vma_address(vma, uprobe->offset); + if (vaddr >= vma->vm_start && vaddr < vma->vm_end) { + ret = install_breakpoint(vma->vm_mm, uprobe, vma, vaddr); + /* Ignore double add: */ + if (ret == -EEXIST) + ret = 0; + } + } + put_uprobe(uprobe); + } + + mutex_unlock(uprobes_mmap_hash(inode)); + + return ret; +} + +static int __init init_uprobes(void) +{ + int i; + + for (i = 0; i < UPROBES_HASH_SZ; i++) { + mutex_init(&uprobes_mutex[i]); + mutex_init(&uprobes_mmap_mutex[i]); + } + return 0; +} + +static void __exit exit_uprobes(void) +{ +} + +module_init(init_uprobes); +module_exit(exit_uprobes); -- cgit v1.1 From 96379f60075c75b261328aa7830ef8aa158247ac Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Wed, 22 Feb 2012 14:45:49 +0530 Subject: uprobes/core: Remove uprobe_opcode_sz uprobe_opcode_sz refers to the smallest instruction size for that architecture. UPROBES_BKPT_INSN_SIZE refers to the size of the breakpoint instruction for that architecture. For now we are assuming that both uprobe_opcode_sz and UPROBES_BKPT_INSN_SIZE are the same for all archs and hence removing uprobe_opcode_sz in favour of UPROBES_BKPT_INSN_SIZE. However if we have to support architectures where the smallest instruction size is different from the size of breakpoint instruction, we may have to re-introduce uprobe_opcode_sz. Signed-off-by: Srikar Dronamraju Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Masami Hiramatsu Cc: Anton Arapov Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Jiri Olsa Cc: Josh Stone Link: http://lkml.kernel.org/r/20120222091549.15880.67020.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/events') diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 884817f..ee496ad 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -244,8 +244,8 @@ static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe, /* poke the new insn in, ASSUMES we don't cross page boundary */ vaddr &= ~PAGE_MASK; - BUG_ON(vaddr + uprobe_opcode_sz > PAGE_SIZE); - memcpy(vaddr_new + vaddr, &opcode, uprobe_opcode_sz); + BUG_ON(vaddr + UPROBES_BKPT_INSN_SIZE > PAGE_SIZE); + memcpy(vaddr_new + vaddr, &opcode, UPROBES_BKPT_INSN_SIZE); kunmap_atomic(vaddr_new); kunmap_atomic(vaddr_old); @@ -293,7 +293,7 @@ static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_ lock_page(page); vaddr_new = kmap_atomic(page); vaddr &= ~PAGE_MASK; - memcpy(opcode, vaddr_new + vaddr, uprobe_opcode_sz); + memcpy(opcode, vaddr_new + vaddr, UPROBES_BKPT_INSN_SIZE); kunmap_atomic(vaddr_new); unlock_page(page); -- cgit v1.1 From 3ff54efdfaace9e9b2b7c1959a865be6b91de96c Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Wed, 22 Feb 2012 14:46:02 +0530 Subject: uprobes/core: Move insn to arch specific structure Few cleanups suggested by Ingo Molnar. - Rename struct uprobe_arch_info to struct arch_uprobe. - Move insn from struct uprobe to struct arch_uprobe. - Make arch specific uprobe functions to accept struct arch_uprobe instead of struct uprobe. - Move struct uprobe to kernel/uprobes.c from include/linux/uprobes.h Signed-off-by: Srikar Dronamraju Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Masami Hiramatsu Cc: Anton Arapov Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Jiri Olsa Cc: Josh Stone Link: http://lkml.kernel.org/r/20120222091602.15880.40249.sendpatchset@srdronam.in.ibm.com [ Made various small improvements ] Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 38 ++++++++++++++++++++++++++------------ 1 file changed, 26 insertions(+), 12 deletions(-) (limited to 'kernel/events') diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index ee496ad..13f1b59 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -65,6 +65,18 @@ struct vma_info { loff_t vaddr; }; +struct uprobe { + struct rb_node rb_node; /* node in the rb tree */ + atomic_t ref; + struct rw_semaphore consumer_rwsem; + struct list_head pending_list; + struct uprobe_consumer *consumers; + struct inode *inode; /* Also hold a ref to inode */ + loff_t offset; + int flags; + struct arch_uprobe arch; +}; + /* * valid_vma: Verify if the specified vma is an executable vma * Relax restrictions while unregistering: vm_flags might have @@ -180,7 +192,7 @@ bool __weak is_bkpt_insn(uprobe_opcode_t *insn) /* * write_opcode - write the opcode at a given virtual address. * @mm: the probed process address space. - * @uprobe: the breakpointing information. + * @arch_uprobe: the breakpointing information. * @vaddr: the virtual address to store the opcode. * @opcode: opcode to be written at @vaddr. * @@ -190,13 +202,14 @@ bool __weak is_bkpt_insn(uprobe_opcode_t *insn) * For mm @mm, write the opcode at @vaddr. * Return 0 (success) or a negative errno. */ -static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe, +static int write_opcode(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr, uprobe_opcode_t opcode) { struct page *old_page, *new_page; struct address_space *mapping; void *vaddr_old, *vaddr_new; struct vm_area_struct *vma; + struct uprobe *uprobe; loff_t addr; int ret; @@ -216,6 +229,7 @@ static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe, if (!valid_vma(vma, is_bkpt_insn(&opcode))) goto put_out; + uprobe = container_of(auprobe, struct uprobe, arch); mapping = uprobe->inode->i_mapping; if (mapping != vma->vm_file->f_mapping) goto put_out; @@ -326,7 +340,7 @@ static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr) * For mm @mm, store the breakpoint instruction at @vaddr. * Return 0 (success) or a negative errno. */ -int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr) +int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr) { int result; @@ -337,7 +351,7 @@ int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long v if (result) return result; - return write_opcode(mm, uprobe, vaddr, UPROBES_BKPT_INSN); + return write_opcode(mm, auprobe, vaddr, UPROBES_BKPT_INSN); } /** @@ -351,7 +365,7 @@ int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long v * Return 0 (success) or a negative errno. */ int __weak -set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, bool verify) +set_orig_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr, bool verify) { if (verify) { int result; @@ -363,7 +377,7 @@ set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, if (result != 1) return result; } - return write_opcode(mm, uprobe, vaddr, *(uprobe_opcode_t *)uprobe->insn); + return write_opcode(mm, auprobe, vaddr, *(uprobe_opcode_t *)auprobe->insn); } static int match_uprobe(struct uprobe *l, struct uprobe *r) @@ -593,13 +607,13 @@ static int copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned /* Instruction at the page-boundary; copy bytes in second page */ if (nbytes < bytes) { - if (__copy_insn(mapping, vma, uprobe->insn + nbytes, + if (__copy_insn(mapping, vma, uprobe->arch.insn + nbytes, bytes - nbytes, uprobe->offset + nbytes)) return -ENOMEM; bytes = nbytes; } - return __copy_insn(mapping, vma, uprobe->insn, bytes, uprobe->offset); + return __copy_insn(mapping, vma, uprobe->arch.insn, bytes, uprobe->offset); } static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, @@ -625,23 +639,23 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, if (ret) return ret; - if (is_bkpt_insn((uprobe_opcode_t *)uprobe->insn)) + if (is_bkpt_insn((uprobe_opcode_t *)uprobe->arch.insn)) return -EEXIST; - ret = arch_uprobes_analyze_insn(mm, uprobe); + ret = arch_uprobes_analyze_insn(mm, &uprobe->arch); if (ret) return ret; uprobe->flags |= UPROBES_COPY_INSN; } - ret = set_bkpt(mm, uprobe, addr); + ret = set_bkpt(mm, &uprobe->arch, addr); return ret; } static void remove_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, loff_t vaddr) { - set_orig_insn(mm, uprobe, (unsigned long)vaddr, true); + set_orig_insn(mm, &uprobe->arch, (unsigned long)vaddr, true); } static void delete_uprobe(struct uprobe *uprobe) -- cgit v1.1 From 35aa621b5ab9d08767f7bc8d209b696df281d715 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 22 Feb 2012 11:37:29 +0100 Subject: uprobes: Update copyright notices Add Peter Zijlstra's copyright to the uprobes code, whose contributions to the uprobes code are not visible in the Git history, because they were backmerged. Also update existing copyright notices to the year 2012. Acked-by: Srikar Dronamraju Cc: Peter Zijlstra Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Link: http://lkml.kernel.org/n/tip-vjqxst502pc1efz7ah8cyht4@git.kernel.org Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel/events') diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 13f1b59..5ce32e3 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -15,10 +15,11 @@ * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * - * Copyright (C) IBM Corporation, 2008-2011 + * Copyright (C) IBM Corporation, 2008-2012 * Authors: * Srikar Dronamraju * Jim Keniston + * Copyright (C) 2011-2012 Red Hat, Inc., Peter Zijlstra */ #include -- cgit v1.1 From 900771a483ef28915a48066d7895d8252315607a Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Mon, 12 Mar 2012 14:55:14 +0530 Subject: uprobes/core: Make macro names consistent Rename macros that refer to individual uprobe to start with UPROBE_ instead of UPROBES_. This is pure cleanup, no functional change intended. Signed-off-by: Srikar Dronamraju Cc: Linus Torvalds Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Linux-mm Cc: Oleg Nesterov Cc: Andi Kleen Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120312092514.5379.36595.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'kernel/events') diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 5ce32e3..0d36bf3 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -177,7 +177,7 @@ out: */ bool __weak is_bkpt_insn(uprobe_opcode_t *insn) { - return *insn == UPROBES_BKPT_INSN; + return *insn == UPROBE_BKPT_INSN; } /* @@ -259,8 +259,8 @@ static int write_opcode(struct mm_struct *mm, struct arch_uprobe *auprobe, /* poke the new insn in, ASSUMES we don't cross page boundary */ vaddr &= ~PAGE_MASK; - BUG_ON(vaddr + UPROBES_BKPT_INSN_SIZE > PAGE_SIZE); - memcpy(vaddr_new + vaddr, &opcode, UPROBES_BKPT_INSN_SIZE); + BUG_ON(vaddr + UPROBE_BKPT_INSN_SIZE > PAGE_SIZE); + memcpy(vaddr_new + vaddr, &opcode, UPROBE_BKPT_INSN_SIZE); kunmap_atomic(vaddr_new); kunmap_atomic(vaddr_old); @@ -308,7 +308,7 @@ static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_ lock_page(page); vaddr_new = kmap_atomic(page); vaddr &= ~PAGE_MASK; - memcpy(opcode, vaddr_new + vaddr, UPROBES_BKPT_INSN_SIZE); + memcpy(opcode, vaddr_new + vaddr, UPROBE_BKPT_INSN_SIZE); kunmap_atomic(vaddr_new); unlock_page(page); @@ -352,7 +352,7 @@ int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned if (result) return result; - return write_opcode(mm, auprobe, vaddr, UPROBES_BKPT_INSN); + return write_opcode(mm, auprobe, vaddr, UPROBE_BKPT_INSN); } /** @@ -635,7 +635,7 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, addr = (unsigned long)vaddr; - if (!(uprobe->flags & UPROBES_COPY_INSN)) { + if (!(uprobe->flags & UPROBE_COPY_INSN)) { ret = copy_insn(uprobe, vma, addr); if (ret) return ret; @@ -647,7 +647,7 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, if (ret) return ret; - uprobe->flags |= UPROBES_COPY_INSN; + uprobe->flags |= UPROBE_COPY_INSN; } ret = set_bkpt(mm, &uprobe->arch, addr); @@ -857,7 +857,7 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer * uprobe->consumers = NULL; __uprobe_unregister(uprobe); } else { - uprobe->flags |= UPROBES_RUN_HANDLER; + uprobe->flags |= UPROBE_RUN_HANDLER; } } @@ -889,7 +889,7 @@ void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consume if (consumer_del(uprobe, consumer)) { if (!uprobe->consumers) { __uprobe_unregister(uprobe); - uprobe->flags &= ~UPROBES_RUN_HANDLER; + uprobe->flags &= ~UPROBE_RUN_HANDLER; } } -- cgit v1.1 From e3343e6a2819ff5d0dfc4bb5c9fb7f9a4d04da73 Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Mon, 12 Mar 2012 14:55:30 +0530 Subject: uprobes/core: Make order of function parameters consistent across functions If a function takes struct uprobe or struct arch_uprobe, then it is passed as the first parameter. This is pure cleanup, no functional change intended. Signed-off-by: Srikar Dronamraju Cc: Linus Torvalds Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Linux-mm Cc: Oleg Nesterov Cc: Andi Kleen Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120312092530.5379.18394.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 93 +++++++++++++++++++++++++------------------------ 1 file changed, 48 insertions(+), 45 deletions(-) (limited to 'kernel/events') diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 0d36bf3..9c5ddff 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -192,8 +192,8 @@ bool __weak is_bkpt_insn(uprobe_opcode_t *insn) /* * write_opcode - write the opcode at a given virtual address. + * @auprobe: arch breakpointing information. * @mm: the probed process address space. - * @arch_uprobe: the breakpointing information. * @vaddr: the virtual address to store the opcode. * @opcode: opcode to be written at @vaddr. * @@ -203,7 +203,7 @@ bool __weak is_bkpt_insn(uprobe_opcode_t *insn) * For mm @mm, write the opcode at @vaddr. * Return 0 (success) or a negative errno. */ -static int write_opcode(struct mm_struct *mm, struct arch_uprobe *auprobe, +static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t opcode) { struct page *old_page, *new_page; @@ -334,14 +334,14 @@ static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr) /** * set_bkpt - store breakpoint at a given address. + * @auprobe: arch specific probepoint information. * @mm: the probed process address space. - * @uprobe: the probepoint information. * @vaddr: the virtual address to insert the opcode. * * For mm @mm, store the breakpoint instruction at @vaddr. * Return 0 (success) or a negative errno. */ -int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr) +int __weak set_bkpt(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) { int result; @@ -352,13 +352,13 @@ int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned if (result) return result; - return write_opcode(mm, auprobe, vaddr, UPROBE_BKPT_INSN); + return write_opcode(auprobe, mm, vaddr, UPROBE_BKPT_INSN); } /** * set_orig_insn - Restore the original instruction. * @mm: the probed process address space. - * @uprobe: the probepoint information. + * @auprobe: arch specific probepoint information. * @vaddr: the virtual address to insert the opcode. * @verify: if true, verify existance of breakpoint instruction. * @@ -366,7 +366,7 @@ int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned * Return 0 (success) or a negative errno. */ int __weak -set_orig_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr, bool verify) +set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, bool verify) { if (verify) { int result; @@ -378,7 +378,7 @@ set_orig_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long v if (result != 1) return result; } - return write_opcode(mm, auprobe, vaddr, *(uprobe_opcode_t *)auprobe->insn); + return write_opcode(auprobe, mm, vaddr, *(uprobe_opcode_t *)auprobe->insn); } static int match_uprobe(struct uprobe *l, struct uprobe *r) @@ -525,30 +525,30 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset) /* Returns the previous consumer */ static struct uprobe_consumer * -consumer_add(struct uprobe *uprobe, struct uprobe_consumer *consumer) +consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc) { down_write(&uprobe->consumer_rwsem); - consumer->next = uprobe->consumers; - uprobe->consumers = consumer; + uc->next = uprobe->consumers; + uprobe->consumers = uc; up_write(&uprobe->consumer_rwsem); - return consumer->next; + return uc->next; } /* - * For uprobe @uprobe, delete the consumer @consumer. - * Return true if the @consumer is deleted successfully + * For uprobe @uprobe, delete the consumer @uc. + * Return true if the @uc is deleted successfully * or return false. */ -static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *consumer) +static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *uc) { struct uprobe_consumer **con; bool ret = false; down_write(&uprobe->consumer_rwsem); for (con = &uprobe->consumers; *con; con = &(*con)->next) { - if (*con == consumer) { - *con = consumer->next; + if (*con == uc) { + *con = uc->next; ret = true; break; } @@ -558,8 +558,8 @@ static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *consumer return ret; } -static int __copy_insn(struct address_space *mapping, - struct vm_area_struct *vma, char *insn, +static int +__copy_insn(struct address_space *mapping, struct vm_area_struct *vma, char *insn, unsigned long nbytes, unsigned long offset) { struct file *filp = vma->vm_file; @@ -590,7 +590,8 @@ static int __copy_insn(struct address_space *mapping, return 0; } -static int copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr) +static int +copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr) { struct address_space *mapping; unsigned long nbytes; @@ -617,8 +618,9 @@ static int copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned return __copy_insn(mapping, vma, uprobe->arch.insn, bytes, uprobe->offset); } -static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, - struct vm_area_struct *vma, loff_t vaddr) +static int +install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, + struct vm_area_struct *vma, loff_t vaddr) { unsigned long addr; int ret; @@ -643,20 +645,21 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, if (is_bkpt_insn((uprobe_opcode_t *)uprobe->arch.insn)) return -EEXIST; - ret = arch_uprobes_analyze_insn(mm, &uprobe->arch); + ret = arch_uprobes_analyze_insn(&uprobe->arch, mm); if (ret) return ret; uprobe->flags |= UPROBE_COPY_INSN; } - ret = set_bkpt(mm, &uprobe->arch, addr); + ret = set_bkpt(&uprobe->arch, mm, addr); return ret; } -static void remove_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, loff_t vaddr) +static void +remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, loff_t vaddr) { - set_orig_insn(mm, &uprobe->arch, (unsigned long)vaddr, true); + set_orig_insn(&uprobe->arch, mm, (unsigned long)vaddr, true); } static void delete_uprobe(struct uprobe *uprobe) @@ -671,9 +674,9 @@ static void delete_uprobe(struct uprobe *uprobe) atomic_dec(&uprobe_events); } -static struct vma_info *__find_next_vma_info(struct list_head *head, - loff_t offset, struct address_space *mapping, - struct vma_info *vi, bool is_register) +static struct vma_info * +__find_next_vma_info(struct address_space *mapping, struct list_head *head, + struct vma_info *vi, loff_t offset, bool is_register) { struct prio_tree_iter iter; struct vm_area_struct *vma; @@ -719,8 +722,8 @@ static struct vma_info *__find_next_vma_info(struct list_head *head, * yet been inserted. */ static struct vma_info * -find_next_vma_info(struct list_head *head, loff_t offset, struct address_space *mapping, - bool is_register) +find_next_vma_info(struct address_space *mapping, struct list_head *head, + loff_t offset, bool is_register) { struct vma_info *vi, *retvi; @@ -729,7 +732,7 @@ find_next_vma_info(struct list_head *head, loff_t offset, struct address_space * return ERR_PTR(-ENOMEM); mutex_lock(&mapping->i_mmap_mutex); - retvi = __find_next_vma_info(head, offset, mapping, vi, is_register); + retvi = __find_next_vma_info(mapping, head, vi, offset, is_register); mutex_unlock(&mapping->i_mmap_mutex); if (!retvi) @@ -754,7 +757,7 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register) ret = 0; for (;;) { - vi = find_next_vma_info(&try_list, uprobe->offset, mapping, is_register); + vi = find_next_vma_info(mapping, &try_list, uprobe->offset, is_register); if (!vi) break; @@ -784,9 +787,9 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register) } if (is_register) - ret = install_breakpoint(mm, uprobe, vma, vi->vaddr); + ret = install_breakpoint(uprobe, mm, vma, vi->vaddr); else - remove_breakpoint(mm, uprobe, vi->vaddr); + remove_breakpoint(uprobe, mm, vi->vaddr); up_read(&mm->mmap_sem); mmput(mm); @@ -823,25 +826,25 @@ static void __uprobe_unregister(struct uprobe *uprobe) * uprobe_register - register a probe * @inode: the file in which the probe has to be placed. * @offset: offset from the start of the file. - * @consumer: information on howto handle the probe.. + * @uc: information on howto handle the probe.. * * Apart from the access refcount, uprobe_register() takes a creation * refcount (thro alloc_uprobe) if and only if this @uprobe is getting * inserted into the rbtree (i.e first consumer for a @inode:@offset * tuple). Creation refcount stops uprobe_unregister from freeing the * @uprobe even before the register operation is complete. Creation - * refcount is released when the last @consumer for the @uprobe + * refcount is released when the last @uc for the @uprobe * unregisters. * * Return errno if it cannot successully install probes * else return 0 (success) */ -int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer) +int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) { struct uprobe *uprobe; int ret; - if (!inode || !consumer || consumer->next) + if (!inode || !uc || uc->next) return -EINVAL; if (offset > i_size_read(inode)) @@ -851,7 +854,7 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer * mutex_lock(uprobes_hash(inode)); uprobe = alloc_uprobe(inode, offset); - if (uprobe && !consumer_add(uprobe, consumer)) { + if (uprobe && !consumer_add(uprobe, uc)) { ret = __uprobe_register(uprobe); if (ret) { uprobe->consumers = NULL; @@ -871,13 +874,13 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer * * uprobe_unregister - unregister a already registered probe. * @inode: the file in which the probe has to be removed. * @offset: offset from the start of the file. - * @consumer: identify which probe if multiple probes are colocated. + * @uc: identify which probe if multiple probes are colocated. */ -void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer) +void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) { struct uprobe *uprobe; - if (!inode || !consumer) + if (!inode || !uc) return; uprobe = find_uprobe(inode, offset); @@ -886,7 +889,7 @@ void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consume mutex_lock(uprobes_hash(inode)); - if (consumer_del(uprobe, consumer)) { + if (consumer_del(uprobe, uc)) { if (!uprobe->consumers) { __uprobe_unregister(uprobe); uprobe->flags &= ~UPROBE_RUN_HANDLER; @@ -993,7 +996,7 @@ int uprobe_mmap(struct vm_area_struct *vma) if (!ret) { vaddr = vma_address(vma, uprobe->offset); if (vaddr >= vma->vm_start && vaddr < vma->vm_end) { - ret = install_breakpoint(vma->vm_mm, uprobe, vma, vaddr); + ret = install_breakpoint(uprobe, vma->vm_mm, vma, vaddr); /* Ignore double add: */ if (ret == -EEXIST) ret = 0; -- cgit v1.1 From 5cb4ac3a583d4ee18c8682ab857e093c4a0d0895 Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Mon, 12 Mar 2012 14:55:45 +0530 Subject: uprobes/core: Rename bkpt to swbp bkpt doesnt seem to be a correct abbrevation for breakpoint. Choice was between bp and breakpoint. Since bp can refer to things other than breakpoint, use swbp to refer to breakpoints. This is pure cleanup, no functional change intended. Signed-off-by: Srikar Dronamraju Cc: Linus Torvalds Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Linux-mm Cc: Oleg Nesterov Cc: Andi Kleen Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120312092545.5379.91251.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) (limited to 'kernel/events') diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 9c5ddff..e56e56a 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -170,14 +170,14 @@ out: } /** - * is_bkpt_insn - check if instruction is breakpoint instruction. + * is_swbp_insn - check if instruction is breakpoint instruction. * @insn: instruction to be checked. - * Default implementation of is_bkpt_insn + * Default implementation of is_swbp_insn * Returns true if @insn is a breakpoint instruction. */ -bool __weak is_bkpt_insn(uprobe_opcode_t *insn) +bool __weak is_swbp_insn(uprobe_opcode_t *insn) { - return *insn == UPROBE_BKPT_INSN; + return *insn == UPROBE_SWBP_INSN; } /* @@ -227,7 +227,7 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, * adding probes in write mapped pages since the breakpoints * might end up in the file copy. */ - if (!valid_vma(vma, is_bkpt_insn(&opcode))) + if (!valid_vma(vma, is_swbp_insn(&opcode))) goto put_out; uprobe = container_of(auprobe, struct uprobe, arch); @@ -259,8 +259,8 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, /* poke the new insn in, ASSUMES we don't cross page boundary */ vaddr &= ~PAGE_MASK; - BUG_ON(vaddr + UPROBE_BKPT_INSN_SIZE > PAGE_SIZE); - memcpy(vaddr_new + vaddr, &opcode, UPROBE_BKPT_INSN_SIZE); + BUG_ON(vaddr + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); + memcpy(vaddr_new + vaddr, &opcode, UPROBE_SWBP_INSN_SIZE); kunmap_atomic(vaddr_new); kunmap_atomic(vaddr_old); @@ -308,7 +308,7 @@ static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_ lock_page(page); vaddr_new = kmap_atomic(page); vaddr &= ~PAGE_MASK; - memcpy(opcode, vaddr_new + vaddr, UPROBE_BKPT_INSN_SIZE); + memcpy(opcode, vaddr_new + vaddr, UPROBE_SWBP_INSN_SIZE); kunmap_atomic(vaddr_new); unlock_page(page); @@ -317,7 +317,7 @@ static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_ return 0; } -static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr) +static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr) { uprobe_opcode_t opcode; int result; @@ -326,14 +326,14 @@ static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr) if (result) return result; - if (is_bkpt_insn(&opcode)) + if (is_swbp_insn(&opcode)) return 1; return 0; } /** - * set_bkpt - store breakpoint at a given address. + * set_swbp - store breakpoint at a given address. * @auprobe: arch specific probepoint information. * @mm: the probed process address space. * @vaddr: the virtual address to insert the opcode. @@ -341,18 +341,18 @@ static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr) * For mm @mm, store the breakpoint instruction at @vaddr. * Return 0 (success) or a negative errno. */ -int __weak set_bkpt(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) +int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) { int result; - result = is_bkpt_at_addr(mm, vaddr); + result = is_swbp_at_addr(mm, vaddr); if (result == 1) return -EEXIST; if (result) return result; - return write_opcode(auprobe, mm, vaddr, UPROBE_BKPT_INSN); + return write_opcode(auprobe, mm, vaddr, UPROBE_SWBP_INSN); } /** @@ -371,7 +371,7 @@ set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long v if (verify) { int result; - result = is_bkpt_at_addr(mm, vaddr); + result = is_swbp_at_addr(mm, vaddr); if (!result) return -EINVAL; @@ -642,7 +642,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, if (ret) return ret; - if (is_bkpt_insn((uprobe_opcode_t *)uprobe->arch.insn)) + if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn)) return -EEXIST; ret = arch_uprobes_analyze_insn(&uprobe->arch, mm); @@ -651,7 +651,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, uprobe->flags |= UPROBE_COPY_INSN; } - ret = set_bkpt(&uprobe->arch, mm, addr); + ret = set_swbp(&uprobe->arch, mm, addr); return ret; } -- cgit v1.1 From 0326f5a94ddea33fa331b2519f4172f4fb387baa Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Tue, 13 Mar 2012 23:30:11 +0530 Subject: uprobes/core: Handle breakpoint and singlestep exceptions Uprobes uses exception notifiers to get to know if a thread hit a breakpoint or a singlestep exception. When a thread hits a uprobe or is singlestepping post a uprobe hit, the uprobe exception notifier sets its TIF_UPROBE bit, which will then be checked on its return to userspace path (do_notify_resume() ->uprobe_notify_resume()), where the consumers handlers are run (in task context) based on the defined filters. Uprobe hits are thread specific and hence we need to maintain information about if a task hit a uprobe, what uprobe was hit, the slot where the original instruction was copied for xol so that it can be singlestepped with appropriate fixups. In some cases, special care is needed for instructions that are executed out of line (xol). These are architecture specific artefacts, such as handling RIP relative instructions on x86_64. Since the instruction at which the uprobe was inserted is executed out of line, architecture specific fixups are added so that the thread continues normal execution in the presence of a uprobe. Postpone the signals until we execute the probed insn. post_xol() path does a recalc_sigpending() before return to user-mode, this ensures the signal can't be lost. Uprobes relies on DIE_DEBUG notification to notify if a singlestep is complete. Adds x86 specific uprobe exception notifiers and appropriate hooks needed to determine a uprobe hit and subsequent post processing. Add requisite x86 fixups for xol for uprobes. Specific cases needing fixups include relative jumps (x86_64), calls, etc. Where possible, we check and skip singlestepping the breakpointed instructions. For now we skip single byte as well as few multibyte nop instructions. However this can be extended to other instructions too. Credits to Oleg Nesterov for suggestions/patches related to signal, breakpoint, singlestep handling code. Signed-off-by: Srikar Dronamraju Cc: Linus Torvalds Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Linux-mm Cc: Oleg Nesterov Cc: Andi Kleen Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120313180011.29771.89027.sendpatchset@srdronam.in.ibm.com [ Performed various cleanliness edits ] Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 323 +++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 319 insertions(+), 4 deletions(-) (limited to 'kernel/events') diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index e56e56a..b807d15 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -30,9 +30,12 @@ #include /* anon_vma_prepare */ #include /* set_pte_at_notify */ #include /* try_to_free_swap */ +#include /* user_enable_single_step */ +#include /* notifier mechanism */ #include +static struct srcu_struct uprobes_srcu; static struct rb_root uprobes_tree = RB_ROOT; static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */ @@ -486,6 +489,9 @@ static struct uprobe *insert_uprobe(struct uprobe *uprobe) u = __insert_uprobe(uprobe); spin_unlock_irqrestore(&uprobes_treelock, flags); + /* For now assume that the instruction need not be single-stepped */ + uprobe->flags |= UPROBE_SKIP_SSTEP; + return u; } @@ -523,6 +529,21 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset) return uprobe; } +static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs) +{ + struct uprobe_consumer *uc; + + if (!(uprobe->flags & UPROBE_RUN_HANDLER)) + return; + + down_read(&uprobe->consumer_rwsem); + for (uc = uprobe->consumers; uc; uc = uc->next) { + if (!uc->filter || uc->filter(uc, current)) + uc->handler(uc, regs); + } + up_read(&uprobe->consumer_rwsem); +} + /* Returns the previous consumer */ static struct uprobe_consumer * consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc) @@ -645,7 +666,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn)) return -EEXIST; - ret = arch_uprobes_analyze_insn(&uprobe->arch, mm); + ret = arch_uprobe_analyze_insn(&uprobe->arch, mm); if (ret) return ret; @@ -662,10 +683,21 @@ remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, loff_t vaddr) set_orig_insn(&uprobe->arch, mm, (unsigned long)vaddr, true); } +/* + * There could be threads that have hit the breakpoint and are entering the + * notifier code and trying to acquire the uprobes_treelock. The thread + * calling delete_uprobe() that is removing the uprobe from the rb_tree can + * race with these threads and might acquire the uprobes_treelock compared + * to some of the breakpoint hit threads. In such a case, the breakpoint + * hit threads will not find the uprobe. The current unregistering thread + * waits till all other threads have hit a breakpoint, to acquire the + * uprobes_treelock before the uprobe is removed from the rbtree. + */ static void delete_uprobe(struct uprobe *uprobe) { unsigned long flags; + synchronize_srcu(&uprobes_srcu); spin_lock_irqsave(&uprobes_treelock, flags); rb_erase(&uprobe->rb_node, &uprobes_tree); spin_unlock_irqrestore(&uprobes_treelock, flags); @@ -1010,6 +1042,288 @@ int uprobe_mmap(struct vm_area_struct *vma) return ret; } +/** + * uprobe_get_swbp_addr - compute address of swbp given post-swbp regs + * @regs: Reflects the saved state of the task after it has hit a breakpoint + * instruction. + * Return the address of the breakpoint instruction. + */ +unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs) +{ + return instruction_pointer(regs) - UPROBE_SWBP_INSN_SIZE; +} + +/* + * Called with no locks held. + * Called in context of a exiting or a exec-ing thread. + */ +void uprobe_free_utask(struct task_struct *t) +{ + struct uprobe_task *utask = t->utask; + + if (t->uprobe_srcu_id != -1) + srcu_read_unlock_raw(&uprobes_srcu, t->uprobe_srcu_id); + + if (!utask) + return; + + if (utask->active_uprobe) + put_uprobe(utask->active_uprobe); + + kfree(utask); + t->utask = NULL; +} + +/* + * Called in context of a new clone/fork from copy_process. + */ +void uprobe_copy_process(struct task_struct *t) +{ + t->utask = NULL; + t->uprobe_srcu_id = -1; +} + +/* + * Allocate a uprobe_task object for the task. + * Called when the thread hits a breakpoint for the first time. + * + * Returns: + * - pointer to new uprobe_task on success + * - NULL otherwise + */ +static struct uprobe_task *add_utask(void) +{ + struct uprobe_task *utask; + + utask = kzalloc(sizeof *utask, GFP_KERNEL); + if (unlikely(!utask)) + return NULL; + + utask->active_uprobe = NULL; + current->utask = utask; + return utask; +} + +/* Prepare to single-step probed instruction out of line. */ +static int +pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long vaddr) +{ + return -EFAULT; +} + +/* + * If we are singlestepping, then ensure this thread is not connected to + * non-fatal signals until completion of singlestep. When xol insn itself + * triggers the signal, restart the original insn even if the task is + * already SIGKILL'ed (since coredump should report the correct ip). This + * is even more important if the task has a handler for SIGSEGV/etc, The + * _same_ instruction should be repeated again after return from the signal + * handler, and SSTEP can never finish in this case. + */ +bool uprobe_deny_signal(void) +{ + struct task_struct *t = current; + struct uprobe_task *utask = t->utask; + + if (likely(!utask || !utask->active_uprobe)) + return false; + + WARN_ON_ONCE(utask->state != UTASK_SSTEP); + + if (signal_pending(t)) { + spin_lock_irq(&t->sighand->siglock); + clear_tsk_thread_flag(t, TIF_SIGPENDING); + spin_unlock_irq(&t->sighand->siglock); + + if (__fatal_signal_pending(t) || arch_uprobe_xol_was_trapped(t)) { + utask->state = UTASK_SSTEP_TRAPPED; + set_tsk_thread_flag(t, TIF_UPROBE); + set_tsk_thread_flag(t, TIF_NOTIFY_RESUME); + } + } + + return true; +} + +/* + * Avoid singlestepping the original instruction if the original instruction + * is a NOP or can be emulated. + */ +static bool can_skip_sstep(struct uprobe *uprobe, struct pt_regs *regs) +{ + if (arch_uprobe_skip_sstep(&uprobe->arch, regs)) + return true; + + uprobe->flags &= ~UPROBE_SKIP_SSTEP; + return false; +} + +/* + * Run handler and ask thread to singlestep. + * Ensure all non-fatal signals cannot interrupt thread while it singlesteps. + */ +static void handle_swbp(struct pt_regs *regs) +{ + struct vm_area_struct *vma; + struct uprobe_task *utask; + struct uprobe *uprobe; + struct mm_struct *mm; + unsigned long bp_vaddr; + + uprobe = NULL; + bp_vaddr = uprobe_get_swbp_addr(regs); + mm = current->mm; + down_read(&mm->mmap_sem); + vma = find_vma(mm, bp_vaddr); + + if (vma && vma->vm_start <= bp_vaddr && valid_vma(vma, false)) { + struct inode *inode; + loff_t offset; + + inode = vma->vm_file->f_mapping->host; + offset = bp_vaddr - vma->vm_start; + offset += (vma->vm_pgoff << PAGE_SHIFT); + uprobe = find_uprobe(inode, offset); + } + + srcu_read_unlock_raw(&uprobes_srcu, current->uprobe_srcu_id); + current->uprobe_srcu_id = -1; + up_read(&mm->mmap_sem); + + if (!uprobe) { + /* No matching uprobe; signal SIGTRAP. */ + send_sig(SIGTRAP, current, 0); + return; + } + + utask = current->utask; + if (!utask) { + utask = add_utask(); + /* Cannot allocate; re-execute the instruction. */ + if (!utask) + goto cleanup_ret; + } + utask->active_uprobe = uprobe; + handler_chain(uprobe, regs); + if (uprobe->flags & UPROBE_SKIP_SSTEP && can_skip_sstep(uprobe, regs)) + goto cleanup_ret; + + utask->state = UTASK_SSTEP; + if (!pre_ssout(uprobe, regs, bp_vaddr)) { + user_enable_single_step(current); + return; + } + +cleanup_ret: + if (utask) { + utask->active_uprobe = NULL; + utask->state = UTASK_RUNNING; + } + if (uprobe) { + if (!(uprobe->flags & UPROBE_SKIP_SSTEP)) + + /* + * cannot singlestep; cannot skip instruction; + * re-execute the instruction. + */ + instruction_pointer_set(regs, bp_vaddr); + + put_uprobe(uprobe); + } +} + +/* + * Perform required fix-ups and disable singlestep. + * Allow pending signals to take effect. + */ +static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs) +{ + struct uprobe *uprobe; + + uprobe = utask->active_uprobe; + if (utask->state == UTASK_SSTEP_ACK) + arch_uprobe_post_xol(&uprobe->arch, regs); + else if (utask->state == UTASK_SSTEP_TRAPPED) + arch_uprobe_abort_xol(&uprobe->arch, regs); + else + WARN_ON_ONCE(1); + + put_uprobe(uprobe); + utask->active_uprobe = NULL; + utask->state = UTASK_RUNNING; + user_disable_single_step(current); + + spin_lock_irq(¤t->sighand->siglock); + recalc_sigpending(); /* see uprobe_deny_signal() */ + spin_unlock_irq(¤t->sighand->siglock); +} + +/* + * On breakpoint hit, breakpoint notifier sets the TIF_UPROBE flag. (and on + * subsequent probe hits on the thread sets the state to UTASK_BP_HIT) and + * allows the thread to return from interrupt. + * + * On singlestep exception, singlestep notifier sets the TIF_UPROBE flag and + * also sets the state to UTASK_SSTEP_ACK and allows the thread to return from + * interrupt. + * + * While returning to userspace, thread notices the TIF_UPROBE flag and calls + * uprobe_notify_resume(). + */ +void uprobe_notify_resume(struct pt_regs *regs) +{ + struct uprobe_task *utask; + + utask = current->utask; + if (!utask || utask->state == UTASK_BP_HIT) + handle_swbp(regs); + else + handle_singlestep(utask, regs); +} + +/* + * uprobe_pre_sstep_notifier gets called from interrupt context as part of + * notifier mechanism. Set TIF_UPROBE flag and indicate breakpoint hit. + */ +int uprobe_pre_sstep_notifier(struct pt_regs *regs) +{ + struct uprobe_task *utask; + + if (!current->mm) + return 0; + + utask = current->utask; + if (utask) + utask->state = UTASK_BP_HIT; + + set_thread_flag(TIF_UPROBE); + current->uprobe_srcu_id = srcu_read_lock_raw(&uprobes_srcu); + + return 1; +} + +/* + * uprobe_post_sstep_notifier gets called in interrupt context as part of notifier + * mechanism. Set TIF_UPROBE flag and indicate completion of singlestep. + */ +int uprobe_post_sstep_notifier(struct pt_regs *regs) +{ + struct uprobe_task *utask = current->utask; + + if (!current->mm || !utask || !utask->active_uprobe) + /* task is currently not uprobed */ + return 0; + + utask->state = UTASK_SSTEP_ACK; + set_thread_flag(TIF_UPROBE); + return 1; +} + +static struct notifier_block uprobe_exception_nb = { + .notifier_call = arch_uprobe_exception_notify, + .priority = INT_MAX-1, /* notified after kprobes, kgdb */ +}; + static int __init init_uprobes(void) { int i; @@ -1018,12 +1332,13 @@ static int __init init_uprobes(void) mutex_init(&uprobes_mutex[i]); mutex_init(&uprobes_mmap_mutex[i]); } - return 0; + init_srcu_struct(&uprobes_srcu); + + return register_die_notifier(&uprobe_exception_nb); } +module_init(init_uprobes); static void __exit exit_uprobes(void) { } - -module_init(init_uprobes); module_exit(exit_uprobes); -- cgit v1.1 From d4b3b6384f98f8692ad0209891ccdbc7e78bbefe Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Fri, 30 Mar 2012 23:56:31 +0530 Subject: uprobes/core: Allocate XOL slots for uprobes use Uprobes executes the original instruction at a probed location out of line. For this, we allocate a page (per mm) upon the first uprobe hit, in the process user address space, divide it into slots that are used to store the actual instructions to be singlestepped. These slots are known as xol (execution out of line) slots. Care is taken to ensure that the allocation is in an unmapped area as close to the top of the user address space as possible, with appropriate permission settings to keep selinux like frameworks happy. Upon a uprobe hit, a free slot is acquired, and is released after the singlestep completes. Lots of improvements courtesy suggestions/inputs from Peter and Oleg. [ Folded a fix for build issue on powerpc fixed and reported by Stephen Rothwell. ] Signed-off-by: Srikar Dronamraju Cc: Linus Torvalds Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Linux-mm Cc: Oleg Nesterov Cc: Andi Kleen Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Anton Arapov Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120330182631.10018.48175.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 215 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 215 insertions(+) (limited to 'kernel/events') diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index b807d15..b395edb 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -35,6 +35,9 @@ #include +#define UINSNS_PER_PAGE (PAGE_SIZE/UPROBE_XOL_SLOT_BYTES) +#define MAX_UPROBE_XOL_SLOTS UINSNS_PER_PAGE + static struct srcu_struct uprobes_srcu; static struct rb_root uprobes_tree = RB_ROOT; @@ -1042,6 +1045,213 @@ int uprobe_mmap(struct vm_area_struct *vma) return ret; } +/* Slot allocation for XOL */ +static int xol_add_vma(struct xol_area *area) +{ + struct mm_struct *mm; + int ret; + + area->page = alloc_page(GFP_HIGHUSER); + if (!area->page) + return -ENOMEM; + + ret = -EALREADY; + mm = current->mm; + + down_write(&mm->mmap_sem); + if (mm->uprobes_state.xol_area) + goto fail; + + ret = -ENOMEM; + + /* Try to map as high as possible, this is only a hint. */ + area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0); + if (area->vaddr & ~PAGE_MASK) { + ret = area->vaddr; + goto fail; + } + + ret = install_special_mapping(mm, area->vaddr, PAGE_SIZE, + VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO, &area->page); + if (ret) + goto fail; + + smp_wmb(); /* pairs with get_xol_area() */ + mm->uprobes_state.xol_area = area; + ret = 0; + +fail: + up_write(&mm->mmap_sem); + if (ret) + __free_page(area->page); + + return ret; +} + +static struct xol_area *get_xol_area(struct mm_struct *mm) +{ + struct xol_area *area; + + area = mm->uprobes_state.xol_area; + smp_read_barrier_depends(); /* pairs with wmb in xol_add_vma() */ + + return area; +} + +/* + * xol_alloc_area - Allocate process's xol_area. + * This area will be used for storing instructions for execution out of + * line. + * + * Returns the allocated area or NULL. + */ +static struct xol_area *xol_alloc_area(void) +{ + struct xol_area *area; + + area = kzalloc(sizeof(*area), GFP_KERNEL); + if (unlikely(!area)) + return NULL; + + area->bitmap = kzalloc(BITS_TO_LONGS(UINSNS_PER_PAGE) * sizeof(long), GFP_KERNEL); + + if (!area->bitmap) + goto fail; + + init_waitqueue_head(&area->wq); + if (!xol_add_vma(area)) + return area; + +fail: + kfree(area->bitmap); + kfree(area); + + return get_xol_area(current->mm); +} + +/* + * uprobe_clear_state - Free the area allocated for slots. + */ +void uprobe_clear_state(struct mm_struct *mm) +{ + struct xol_area *area = mm->uprobes_state.xol_area; + + if (!area) + return; + + put_page(area->page); + kfree(area->bitmap); + kfree(area); +} + +/* + * uprobe_reset_state - Free the area allocated for slots. + */ +void uprobe_reset_state(struct mm_struct *mm) +{ + mm->uprobes_state.xol_area = NULL; +} + +/* + * - search for a free slot. + */ +static unsigned long xol_take_insn_slot(struct xol_area *area) +{ + unsigned long slot_addr; + int slot_nr; + + do { + slot_nr = find_first_zero_bit(area->bitmap, UINSNS_PER_PAGE); + if (slot_nr < UINSNS_PER_PAGE) { + if (!test_and_set_bit(slot_nr, area->bitmap)) + break; + + slot_nr = UINSNS_PER_PAGE; + continue; + } + wait_event(area->wq, (atomic_read(&area->slot_count) < UINSNS_PER_PAGE)); + } while (slot_nr >= UINSNS_PER_PAGE); + + slot_addr = area->vaddr + (slot_nr * UPROBE_XOL_SLOT_BYTES); + atomic_inc(&area->slot_count); + + return slot_addr; +} + +/* + * xol_get_insn_slot - If was not allocated a slot, then + * allocate a slot. + * Returns the allocated slot address or 0. + */ +static unsigned long xol_get_insn_slot(struct uprobe *uprobe, unsigned long slot_addr) +{ + struct xol_area *area; + unsigned long offset; + void *vaddr; + + area = get_xol_area(current->mm); + if (!area) { + area = xol_alloc_area(); + if (!area) + return 0; + } + current->utask->xol_vaddr = xol_take_insn_slot(area); + + /* + * Initialize the slot if xol_vaddr points to valid + * instruction slot. + */ + if (unlikely(!current->utask->xol_vaddr)) + return 0; + + current->utask->vaddr = slot_addr; + offset = current->utask->xol_vaddr & ~PAGE_MASK; + vaddr = kmap_atomic(area->page); + memcpy(vaddr + offset, uprobe->arch.insn, MAX_UINSN_BYTES); + kunmap_atomic(vaddr); + + return current->utask->xol_vaddr; +} + +/* + * xol_free_insn_slot - If slot was earlier allocated by + * @xol_get_insn_slot(), make the slot available for + * subsequent requests. + */ +static void xol_free_insn_slot(struct task_struct *tsk) +{ + struct xol_area *area; + unsigned long vma_end; + unsigned long slot_addr; + + if (!tsk->mm || !tsk->mm->uprobes_state.xol_area || !tsk->utask) + return; + + slot_addr = tsk->utask->xol_vaddr; + + if (unlikely(!slot_addr || IS_ERR_VALUE(slot_addr))) + return; + + area = tsk->mm->uprobes_state.xol_area; + vma_end = area->vaddr + PAGE_SIZE; + if (area->vaddr <= slot_addr && slot_addr < vma_end) { + unsigned long offset; + int slot_nr; + + offset = slot_addr - area->vaddr; + slot_nr = offset / UPROBE_XOL_SLOT_BYTES; + if (slot_nr >= UINSNS_PER_PAGE) + return; + + clear_bit(slot_nr, area->bitmap); + atomic_dec(&area->slot_count); + if (waitqueue_active(&area->wq)) + wake_up(&area->wq); + + tsk->utask->xol_vaddr = 0; + } +} + /** * uprobe_get_swbp_addr - compute address of swbp given post-swbp regs * @regs: Reflects the saved state of the task after it has hit a breakpoint @@ -1070,6 +1280,7 @@ void uprobe_free_utask(struct task_struct *t) if (utask->active_uprobe) put_uprobe(utask->active_uprobe); + xol_free_insn_slot(t); kfree(utask); t->utask = NULL; } @@ -1108,6 +1319,9 @@ static struct uprobe_task *add_utask(void) static int pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long vaddr) { + if (xol_get_insn_slot(uprobe, vaddr) && !arch_uprobe_pre_xol(&uprobe->arch, regs)) + return 0; + return -EFAULT; } @@ -1252,6 +1466,7 @@ static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs) utask->active_uprobe = NULL; utask->state = UTASK_RUNNING; user_disable_single_step(current); + xol_free_insn_slot(current); spin_lock_irq(¤t->sighand->siglock); recalc_sigpending(); /* see uprobe_deny_signal() */ -- cgit v1.1 From 682968e0c425c60f0dde37977e5beb2b12ddc4cc Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Fri, 30 Mar 2012 23:56:46 +0530 Subject: uprobes/core: Optimize probe hits with the help of a counter Maintain a per-mm counter: number of uprobes that are inserted on this process address space. This counter can be used at probe hit time to determine if we need a lookup in the uprobes rbtree. Everytime a probe gets inserted successfully, the probe count is incremented and everytime a probe gets removed, the probe count is decremented. The new uprobe_munmap hook ensures the count is correct on a unmap or remap of a region. We expect that once a uprobe_munmap() is called, the vma goes away. So uprobe_unregister() finding a probe to unregister would either mean unmap event hasnt occurred yet or a mmap event on the same executable file occured after a unmap event. Additionally, uprobe_mmap hook now also gets called: a. on every executable vma that is COWed at fork. b. a vma of interest is newly mapped; breakpoint insertion also happens at the required address. On process creation, make sure the probes count in the child is set correctly. Special cases that are taken care include: a. mremap b. VM_DONTCOPY vmas on fork() c. insertion/removal races in the parent during fork(). Signed-off-by: Srikar Dronamraju Cc: Linus Torvalds Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Linux-mm Cc: Oleg Nesterov Cc: Andi Kleen Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Anton Arapov Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120330182646.10018.85805.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 119 ++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 111 insertions(+), 8 deletions(-) (limited to 'kernel/events') diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index b395edb..29e881b 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -642,6 +642,29 @@ copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr) return __copy_insn(mapping, vma, uprobe->arch.insn, bytes, uprobe->offset); } +/* + * How mm->uprobes_state.count gets updated + * uprobe_mmap() increments the count if + * - it successfully adds a breakpoint. + * - it cannot add a breakpoint, but sees that there is a underlying + * breakpoint (via a is_swbp_at_addr()). + * + * uprobe_munmap() decrements the count if + * - it sees a underlying breakpoint, (via is_swbp_at_addr) + * (Subsequent uprobe_unregister wouldnt find the breakpoint + * unless a uprobe_mmap kicks in, since the old vma would be + * dropped just after uprobe_munmap.) + * + * uprobe_register increments the count if: + * - it successfully adds a breakpoint. + * + * uprobe_unregister decrements the count if: + * - it sees a underlying breakpoint and removes successfully. + * (via is_swbp_at_addr) + * (Subsequent uprobe_munmap wouldnt find the breakpoint + * since there is no underlying breakpoint after the + * breakpoint removal.) + */ static int install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, struct vm_area_struct *vma, loff_t vaddr) @@ -675,7 +698,19 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, uprobe->flags |= UPROBE_COPY_INSN; } + + /* + * Ideally, should be updating the probe count after the breakpoint + * has been successfully inserted. However a thread could hit the + * breakpoint we just inserted even before the probe count is + * incremented. If this is the first breakpoint placed, breakpoint + * notifier might ignore uprobes and pass the trap to the thread. + * Hence increment before and decrement on failure. + */ + atomic_inc(&mm->uprobes_state.count); ret = set_swbp(&uprobe->arch, mm, addr); + if (ret) + atomic_dec(&mm->uprobes_state.count); return ret; } @@ -683,7 +718,8 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, static void remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, loff_t vaddr) { - set_orig_insn(&uprobe->arch, mm, (unsigned long)vaddr, true); + if (!set_orig_insn(&uprobe->arch, mm, (unsigned long)vaddr, true)) + atomic_dec(&mm->uprobes_state.count); } /* @@ -1009,7 +1045,7 @@ int uprobe_mmap(struct vm_area_struct *vma) struct list_head tmp_list; struct uprobe *uprobe, *u; struct inode *inode; - int ret; + int ret, count; if (!atomic_read(&uprobe_events) || !valid_vma(vma, true)) return 0; @@ -1023,6 +1059,7 @@ int uprobe_mmap(struct vm_area_struct *vma) build_probe_list(inode, &tmp_list); ret = 0; + count = 0; list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) { loff_t vaddr; @@ -1030,21 +1067,85 @@ int uprobe_mmap(struct vm_area_struct *vma) list_del(&uprobe->pending_list); if (!ret) { vaddr = vma_address(vma, uprobe->offset); - if (vaddr >= vma->vm_start && vaddr < vma->vm_end) { - ret = install_breakpoint(uprobe, vma->vm_mm, vma, vaddr); - /* Ignore double add: */ - if (ret == -EEXIST) - ret = 0; + + if (vaddr < vma->vm_start || vaddr >= vma->vm_end) { + put_uprobe(uprobe); + continue; } + + ret = install_breakpoint(uprobe, vma->vm_mm, vma, vaddr); + + /* Ignore double add: */ + if (ret == -EEXIST) { + ret = 0; + + if (!is_swbp_at_addr(vma->vm_mm, vaddr)) + continue; + + /* + * Unable to insert a breakpoint, but + * breakpoint lies underneath. Increment the + * probe count. + */ + atomic_inc(&vma->vm_mm->uprobes_state.count); + } + + if (!ret) + count++; } put_uprobe(uprobe); } mutex_unlock(uprobes_mmap_hash(inode)); + if (ret) + atomic_sub(count, &vma->vm_mm->uprobes_state.count); + return ret; } +/* + * Called in context of a munmap of a vma. + */ +void uprobe_munmap(struct vm_area_struct *vma) +{ + struct list_head tmp_list; + struct uprobe *uprobe, *u; + struct inode *inode; + + if (!atomic_read(&uprobe_events) || !valid_vma(vma, false)) + return; + + if (!atomic_read(&vma->vm_mm->uprobes_state.count)) + return; + + inode = vma->vm_file->f_mapping->host; + if (!inode) + return; + + INIT_LIST_HEAD(&tmp_list); + mutex_lock(uprobes_mmap_hash(inode)); + build_probe_list(inode, &tmp_list); + + list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) { + loff_t vaddr; + + list_del(&uprobe->pending_list); + vaddr = vma_address(vma, uprobe->offset); + + if (vaddr >= vma->vm_start && vaddr < vma->vm_end) { + /* + * An unregister could have removed the probe before + * unmap. So check before we decrement the count. + */ + if (is_swbp_at_addr(vma->vm_mm, vaddr) == 1) + atomic_dec(&vma->vm_mm->uprobes_state.count); + } + put_uprobe(uprobe); + } + mutex_unlock(uprobes_mmap_hash(inode)); +} + /* Slot allocation for XOL */ static int xol_add_vma(struct xol_area *area) { @@ -1150,6 +1251,7 @@ void uprobe_clear_state(struct mm_struct *mm) void uprobe_reset_state(struct mm_struct *mm) { mm->uprobes_state.xol_area = NULL; + atomic_set(&mm->uprobes_state.count, 0); } /* @@ -1504,7 +1606,8 @@ int uprobe_pre_sstep_notifier(struct pt_regs *regs) { struct uprobe_task *utask; - if (!current->mm) + if (!current->mm || !atomic_read(¤t->mm->uprobes_state.count)) + /* task is currently not uprobed */ return 0; utask = current->utask; -- cgit v1.1 From 7396fa818d6278694a44840f389ddc40a3269a9a Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Wed, 11 Apr 2012 16:05:16 +0530 Subject: uprobes/core: Make background page replacement logic account for rss_stat counters Background page replacement logic adds a new anonymous page instead of a file backed (while inserting a breakpoint) / anonymous page (while removing a breakpoint). Hence the uprobes logic should take care to update the task->ss_stat counters accordingly. This bug became apparent courtesy of commit c3f0327f8e9d ("mm: add rss counters consistency check"). Signed-off-by: Srikar Dronamraju Cc: Linus Torvalds Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Linux-mm Cc: Oleg Nesterov Cc: Andi Kleen Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Anton Arapov Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120411103516.23245.2700.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'kernel/events') diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 29e881b..c5caeec 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -160,6 +160,11 @@ static int __replace_page(struct vm_area_struct *vma, struct page *page, struct get_page(kpage); page_add_new_anon_rmap(kpage, vma, addr); + if (!PageAnon(page)) { + dec_mm_counter(mm, MM_FILEPAGES); + inc_mm_counter(mm, MM_ANONPAGES); + } + flush_cache_page(vma, addr, pte_pfn(*ptep)); ptep_clear_flush(vma, addr, ptep); set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot)); -- cgit v1.1 From cbc91f71b51b8335f1fc7ccfca8011f31a717367 Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Wed, 11 Apr 2012 16:05:27 +0530 Subject: uprobes/core: Decrement uprobe count before the pages are unmapped Uprobes has a callback (uprobe_munmap()) in the unmap path to maintain the uprobes count. In the exit path this callback gets called in unlink_file_vma(). However by the time unlink_file_vma() is called, the pages would have been unmapped (in unmap_vmas()) and the task->rss_stat counts accounted (in zap_pte_range()). If the exiting process has probepoints, uprobe_munmap() checks if the breakpoint instruction was around before decrementing the probe count. This results in a file backed page being reread by uprobe_munmap() and hence it does not find the breakpoint. This patch fixes this problem by moving the callback to unmap_single_vma(). Since unmap_single_vma() may not unmap the complete vma, add start and end parameters to uprobe_munmap(). This bug became apparent courtesy of commit c3f0327f8e9d ("mm: add rss counters consistency check"). Signed-off-by: Srikar Dronamraju Cc: Linus Torvalds Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Linux-mm Cc: Oleg Nesterov Cc: Andi Kleen Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Anton Arapov Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120411103527.23245.9835.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/events') diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index c5caeec..985be4d 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1112,7 +1112,7 @@ int uprobe_mmap(struct vm_area_struct *vma) /* * Called in context of a munmap of a vma. */ -void uprobe_munmap(struct vm_area_struct *vma) +void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end) { struct list_head tmp_list; struct uprobe *uprobe, *u; @@ -1138,7 +1138,7 @@ void uprobe_munmap(struct vm_area_struct *vma) list_del(&uprobe->pending_list); vaddr = vma_address(vma, uprobe->offset); - if (vaddr >= vma->vm_start && vaddr < vma->vm_end) { + if (vaddr >= start && vaddr < end) { /* * An unregister could have removed the probe before * unmap. So check before we decrement the count. -- cgit v1.1