diff options
| -rw-r--r-- | arch/avr32/mm/fault.c | 18 | ||||
| -rw-r--r-- | arch/powerpc/Kconfig | 3 | ||||
| -rw-r--r-- | arch/powerpc/Kconfig.debug | 1 | ||||
| -rw-r--r-- | arch/s390/Kconfig | 3 | ||||
| -rw-r--r-- | arch/s390/Kconfig.debug | 1 | ||||
| -rw-r--r-- | arch/sparc/Kconfig | 3 | ||||
| -rw-r--r-- | arch/sparc/Kconfig.debug | 3 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 3 | ||||
| -rw-r--r-- | arch/x86/Kconfig.debug | 1 | ||||
| -rw-r--r-- | include/linux/mm_types.h | 4 | ||||
| -rw-r--r-- | include/linux/page-debug-flags.h | 30 | ||||
| -rw-r--r-- | include/linux/poison.h | 3 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 1 | ||||
| -rw-r--r-- | mm/Kconfig.debug | 17 | ||||
| -rw-r--r-- | mm/Makefile | 1 | ||||
| -rw-r--r-- | mm/debug-pagealloc.c | 129 |
16 files changed, 202 insertions, 19 deletions
diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c index ce4e429..62d4abb 100644 --- a/arch/avr32/mm/fault.c +++ b/arch/avr32/mm/fault.c @@ -250,21 +250,3 @@ asmlinkage void do_bus_error(unsigned long addr, int write_access, dump_dtlb(); die("Bus Error", regs, SIGKILL); } - -/* - * This functionality is currently not possible to implement because - * we're using segmentation to ensure a fixed mapping of the kernel - * virtual address space. - * - * It would be possible to implement this, but it would require us to - * disable segmentation at startup and load the kernel mappings into - * the TLB like any other pages. There will be lots of trickery to - * avoid recursive invocation of the TLB miss handler, though... - */ -#ifdef CONFIG_DEBUG_PAGEALLOC -void kernel_map_pages(struct page *page, int numpages, int enable) -{ - -} -EXPORT_SYMBOL(kernel_map_pages); -#endif diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index ad6b1c0..45192dc 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -228,6 +228,9 @@ config PPC_OF_PLATFORM_PCI depends on PPC64 # not supported on 32 bits yet default n +config ARCH_SUPPORTS_DEBUG_PAGEALLOC + def_bool y + source "init/Kconfig" source "kernel/Kconfig.freezer" diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug index 22091bb..6aa0b5e 100644 --- a/arch/powerpc/Kconfig.debug +++ b/arch/powerpc/Kconfig.debug @@ -30,6 +30,7 @@ config DEBUG_STACK_USAGE config DEBUG_PAGEALLOC bool "Debug page memory allocations" depends on DEBUG_KERNEL && !HIBERNATION + depends on ARCH_SUPPORTS_DEBUG_PAGEALLOC help Unmap pages from the kernel linear mapping after free_pages(). This results in a large slowdown, but helps to find certain types diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 2a8af5e..dcb667c 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -72,6 +72,9 @@ config PGSTE config VIRT_CPU_ACCOUNTING def_bool y +config ARCH_SUPPORTS_DEBUG_PAGEALLOC + def_bool y + mainmenu "Linux Kernel Configuration" config S390 diff --git a/arch/s390/Kconfig.debug b/arch/s390/Kconfig.debug index 4599fa0..7e297a3 100644 --- a/arch/s390/Kconfig.debug +++ b/arch/s390/Kconfig.debug @@ -9,6 +9,7 @@ source "lib/Kconfig.debug" config DEBUG_PAGEALLOC bool "Debug page memory allocations" depends on DEBUG_KERNEL + depends on ARCH_SUPPORTS_DEBUG_PAGEALLOC help Unmap pages from the kernel linear mapping after free_pages(). This results in a slowdown, but helps to find certain types of diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index c3ea215..cc12cd4 100644 --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -124,6 +124,9 @@ config ARCH_NO_VIRT_TO_BUS config OF def_bool y +config ARCH_SUPPORTS_DEBUG_PAGEALLOC + def_bool y if SPARC64 + source "init/Kconfig" source "kernel/Kconfig.freezer" diff --git a/arch/sparc/Kconfig.debug b/arch/sparc/Kconfig.debug index b8a15e2..d001b42 100644 --- a/arch/sparc/Kconfig.debug +++ b/arch/sparc/Kconfig.debug @@ -24,7 +24,8 @@ config STACK_DEBUG config DEBUG_PAGEALLOC bool "Debug page memory allocations" - depends on SPARC64 && DEBUG_KERNEL && !HIBERNATION + depends on DEBUG_KERNEL && !HIBERNATION + depends on ARCH_SUPPORTS_DEBUG_PAGEALLOC help Unmap pages from the kernel linear mapping after free_pages(). This results in a large slowdown, but helps to find certain types diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 45161b8..748e50a 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -165,6 +165,9 @@ config AUDIT_ARCH config ARCH_SUPPORTS_OPTIMIZED_INLINING def_bool y +config ARCH_SUPPORTS_DEBUG_PAGEALLOC + def_bool y + # Use the generic interrupt handling code in kernel/irq/: config GENERIC_HARDIRQS bool diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index fdb45df..a345cb5 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -75,6 +75,7 @@ config DEBUG_STACK_USAGE config DEBUG_PAGEALLOC bool "Debug page memory allocations" depends on DEBUG_KERNEL + depends on ARCH_SUPPORTS_DEBUG_PAGEALLOC ---help--- Unmap pages from the kernel linear mapping after free_pages(). This results in a large slowdown, but helps to find certain types diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index d84feb7..ddadb4d 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -11,6 +11,7 @@ #include <linux/rwsem.h> #include <linux/completion.h> #include <linux/cpumask.h> +#include <linux/page-debug-flags.h> #include <asm/page.h> #include <asm/mmu.h> @@ -174,6 +175,9 @@ struct vm_area_struct { #ifdef CONFIG_NUMA struct mempolicy *vm_policy; /* NUMA policy for the VMA */ #endif +#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS + unsigned long debug_flags; /* Use atomic bitops on this */ +#endif }; struct core_thread { diff --git a/include/linux/page-debug-flags.h b/include/linux/page-debug-flags.h new file mode 100644 index 0000000..b0638fd9 --- /dev/null +++ b/include/linux/page-debug-flags.h @@ -0,0 +1,30 @@ +#ifndef LINUX_PAGE_DEBUG_FLAGS_H +#define LINUX_PAGE_DEBUG_FLAGS_H + +/* + * page->debug_flags bits: + * + * PAGE_DEBUG_FLAG_POISON is set for poisoned pages. This is used to + * implement generic debug pagealloc feature. The pages are filled with + * poison patterns and set this flag after free_pages(). The poisoned + * pages are verified whether the patterns are not corrupted and clear + * the flag before alloc_pages(). + */ + +enum page_debug_flags { + PAGE_DEBUG_FLAG_POISON, /* Page is poisoned */ +}; + +/* + * Ensure that CONFIG_WANT_PAGE_DEBUG_FLAGS reliably + * gets turned off when no debug features are enabling it! + */ + +#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS +#if !defined(CONFIG_PAGE_POISONING) \ +/* && !defined(CONFIG_PAGE_DEBUG_SOMETHING_ELSE) && ... */ +#error WANT_PAGE_DEBUG_FLAGS is turned on with no debug features! +#endif +#endif /* CONFIG_WANT_PAGE_DEBUG_FLAGS */ + +#endif /* LINUX_PAGE_DEBUG_FLAGS_H */ diff --git a/include/linux/poison.h b/include/linux/poison.h index 9f31683..6729f7d 100644 --- a/include/linux/poison.h +++ b/include/linux/poison.h @@ -17,6 +17,9 @@ */ #define TIMER_ENTRY_STATIC ((void *) 0x74737461) +/********** mm/debug-pagealloc.c **********/ +#define PAGE_POISON 0xaa + /********** mm/slab.c **********/ /* * Magic nums for obj red zoning. diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 58bfe7e..9638d99 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -796,6 +796,7 @@ config SYSCTL_SYSCALL_CHECK to properly maintain and use. This enables checks that help you to keep things correct. +source mm/Kconfig.debug source kernel/trace/Kconfig config PROVIDE_OHCI1394_DMA_INIT diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug new file mode 100644 index 0000000..c8d62d4 --- /dev/null +++ b/mm/Kconfig.debug @@ -0,0 +1,17 @@ +config WANT_PAGE_DEBUG_FLAGS + bool + +config PAGE_POISONING + bool "Debug page memory allocations" + depends on DEBUG_KERNEL && !ARCH_SUPPORTS_DEBUG_PAGEALLOC + depends on !HIBERNATION + select DEBUG_PAGEALLOC + select WANT_PAGE_DEBUG_FLAGS + help + Fill the pages with poison patterns after free_pages() and verify + the patterns before alloc_pages(). This results in a large slowdown, + but helps to find certain types of memory corruptions. + + This option cannot enalbe with hibernation. Otherwise, it will get + wrong messages for memory corruption because the free pages are not + saved to the suspend image. diff --git a/mm/Makefile b/mm/Makefile index 818569b6..ec73c68 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -24,6 +24,7 @@ obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o obj-$(CONFIG_TMPFS_POSIX_ACL) += shmem_acl.o obj-$(CONFIG_SLOB) += slob.o obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o +obj-$(CONFIG_PAGE_POISONING) += debug-pagealloc.o obj-$(CONFIG_SLAB) += slab.o obj-$(CONFIG_SLUB) += slub.o obj-$(CONFIG_FAILSLAB) += failslab.o diff --git a/mm/debug-pagealloc.c b/mm/debug-pagealloc.c new file mode 100644 index 0000000..a1e3324 --- /dev/null +++ b/mm/debug-pagealloc.c @@ -0,0 +1,129 @@ +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/page-debug-flags.h> +#include <linux/poison.h> + +static inline void set_page_poison(struct page *page) +{ + __set_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags); +} + +static inline void clear_page_poison(struct page *page) +{ + __clear_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags); +} + +static inline bool page_poison(struct page *page) +{ + return test_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags); +} + +static void poison_highpage(struct page *page) +{ + /* + * Page poisoning for highmem pages is not implemented. + * + * This can be called from interrupt contexts. + * So we need to create a new kmap_atomic slot for this + * application and it will need interrupt protection. + */ +} + +static void poison_page(struct page *page) +{ + void *addr; + + if (PageHighMem(page)) { + poison_highpage(page); + return; + } + set_page_poison(page); + addr = page_address(page); + memset(addr, PAGE_POISON, PAGE_SIZE); +} + +static void poison_pages(struct page *page, int n) +{ + int i; + + for (i = 0; i < n; i++) + poison_page(page + i); +} + +static bool single_bit_flip(unsigned char a, unsigned char b) +{ + unsigned char error = a ^ b; + + return error && !(error & (error - 1)); +} + +static void check_poison_mem(unsigned char *mem, size_t bytes) +{ + unsigned char *start; + unsigned char *end; + + for (start = mem; start < mem + bytes; start++) { + if (*start != PAGE_POISON) + break; + } + if (start == mem + bytes) + return; + + for (end = mem + bytes - 1; end > start; end--) { + if (*end != PAGE_POISON) + break; + } + + if (!printk_ratelimit()) + return; + else if (start == end && single_bit_flip(*start, PAGE_POISON)) + printk(KERN_ERR "pagealloc: single bit error\n"); + else + printk(KERN_ERR "pagealloc: memory corruption\n"); + + print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start, + end - start + 1, 1); + dump_stack(); +} + +static void unpoison_highpage(struct page *page) +{ + /* + * See comment in poison_highpage(). + * Highmem pages should not be poisoned for now + */ + BUG_ON(page_poison(page)); +} + +static void unpoison_page(struct page *page) +{ + if (PageHighMem(page)) { + unpoison_highpage(page); + return; + } + if (page_poison(page)) { + void *addr = page_address(page); + + check_poison_mem(addr, PAGE_SIZE); + clear_page_poison(page); + } +} + +static void unpoison_pages(struct page *page, int n) +{ + int i; + + for (i = 0; i < n; i++) + unpoison_page(page + i); +} + +void kernel_map_pages(struct page *page, int numpages, int enable) +{ + if (!debug_pagealloc_enabled) + return; + + if (enable) + unpoison_pages(page, numpages); + else + poison_pages(page, numpages); +} |
