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author | kib <kib@FreeBSD.org> | 2007-11-05 11:36:16 +0000 |
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committer | kib <kib@FreeBSD.org> | 2007-11-05 11:36:16 +0000 |
commit | 9ae733819b7cdf0eef51ba1b18d39feb136a9dbf (patch) | |
tree | cccec36134d2cab5ce1eabb67dcaab5981e9beb0 /sys/vm/vm_glue.c | |
parent | f3f033b9b90ea07350fbe7483af3d9636cb31d1d (diff) | |
download | FreeBSD-src-9ae733819b7cdf0eef51ba1b18d39feb136a9dbf.zip FreeBSD-src-9ae733819b7cdf0eef51ba1b18d39feb136a9dbf.tar.gz |
Fix for the panic("vm_thread_new: kstack allocation failed") and
silent NULL pointer dereference in the i386 and sparc64 pmap_pinit()
when the kmem_alloc_nofault() failed to allocate address space. Both
functions now return error instead of panicing or dereferencing NULL.
As consequence, vmspace_exec() and vmspace_unshare() returns the errno
int. struct vmspace arg was added to vm_forkproc() to avoid dealing
with failed allocation when most of the fork1() job is already done.
The kernel stack for the thread is now set up in the thread_alloc(),
that itself may return NULL. Also, allocation of the first process
thread is performed in the fork1() to properly deal with stack
allocation failure. proc_linkup() is separated into proc_linkup()
called from fork1(), and proc_linkup0(), that is used to set up the
kernel process (was known as swapper).
In collaboration with: Peter Holm
Reviewed by: jhb
Diffstat (limited to 'sys/vm/vm_glue.c')
-rw-r--r-- | sys/vm/vm_glue.c | 33 |
1 files changed, 22 insertions, 11 deletions
diff --git a/sys/vm/vm_glue.c b/sys/vm/vm_glue.c index caa8aa0..258b886 100644 --- a/sys/vm/vm_glue.c +++ b/sys/vm/vm_glue.c @@ -321,7 +321,7 @@ vm_imgact_unmap_page(struct sf_buf *sf) * This routine directly affects the fork perf for a process and * create performance for a thread. */ -void +int vm_thread_new(struct thread *td, int pages) { vm_object_t ksobj; @@ -338,18 +338,22 @@ vm_thread_new(struct thread *td, int pages) * Allocate an object for the kstack. */ ksobj = vm_object_allocate(OBJT_DEFAULT, pages); - td->td_kstack_obj = ksobj; /* * Get a kernel virtual address for this thread's kstack. */ ks = kmem_alloc_nofault(kernel_map, (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); - if (ks == 0) - panic("vm_thread_new: kstack allocation failed"); + if (ks == 0) { + printf("vm_thread_new: kstack allocation failed\n"); + vm_object_deallocate(ksobj); + return (0); + } + if (KSTACK_GUARD_PAGES != 0) { pmap_qremove(ks, KSTACK_GUARD_PAGES); ks += KSTACK_GUARD_PAGES * PAGE_SIZE; } + td->td_kstack_obj = ksobj; td->td_kstack = ks; /* * Knowing the number of pages allocated is useful when you @@ -372,6 +376,7 @@ vm_thread_new(struct thread *td, int pages) } VM_OBJECT_UNLOCK(ksobj); pmap_qenter(ks, ma, pages); + return (1); } /* @@ -403,6 +408,7 @@ vm_thread_dispose(struct thread *td) vm_object_deallocate(ksobj); kmem_free(kernel_map, ks - (KSTACK_GUARD_PAGES * PAGE_SIZE), (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); + td->td_kstack = 0; } /* @@ -468,7 +474,7 @@ vm_thread_swapin(struct thread *td) /* * Set up a variable-sized alternate kstack. */ -void +int vm_thread_new_altkstack(struct thread *td, int pages) { @@ -476,7 +482,7 @@ vm_thread_new_altkstack(struct thread *td, int pages) td->td_altkstack_obj = td->td_kstack_obj; td->td_altkstack_pages = td->td_kstack_pages; - vm_thread_new(td, pages); + return (vm_thread_new(td, pages)); } /* @@ -504,14 +510,16 @@ vm_thread_dispose_altkstack(struct thread *td) * ready to run. The new process is set up so that it returns directly * to user mode to avoid stack copying and relocation problems. */ -void -vm_forkproc(td, p2, td2, flags) +int +vm_forkproc(td, p2, td2, vm2, flags) struct thread *td; struct proc *p2; struct thread *td2; + struct vmspace *vm2; int flags; { struct proc *p1 = td->td_proc; + int error; if ((flags & RFPROC) == 0) { /* @@ -521,11 +529,13 @@ vm_forkproc(td, p2, td2, flags) */ if ((flags & RFMEM) == 0) { if (p1->p_vmspace->vm_refcnt > 1) { - vmspace_unshare(p1); + error = vmspace_unshare(p1); + if (error) + return (error); } } cpu_fork(td, p2, td2, flags); - return; + return (0); } if (flags & RFMEM) { @@ -538,7 +548,7 @@ vm_forkproc(td, p2, td2, flags) } if ((flags & RFMEM) == 0) { - p2->p_vmspace = vmspace_fork(p1->p_vmspace); + p2->p_vmspace = vm2; if (p1->p_vmspace->vm_shm) shmfork(p1, p2); } @@ -548,6 +558,7 @@ vm_forkproc(td, p2, td2, flags) * and make the child ready to run. */ cpu_fork(td, p2, td2, flags); + return (0); } /* |