[PATCH] kmemcheck: Test the full object in kmemcheck_is_obj_initialized()
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From: Catalin Marinas on 8 Feb 2010 06:20 This is a fix for bug #14845 (bugzilla.kernel.org). The update_checksum() function in mm/kmemleak.c calls kmemcheck_is_obj_initialised() before scanning an object. When KMEMCHECK_PARTIAL_OK is enabled, this function returns true. However, the crc32_le() reads smaller intervals (32-bit) for which kmemleak_is_obj_initialised() may be false leading to a kmemcheck warning. Note that kmemcheck_is_obj_initialized() is currently only used by kmemleak before scanning a memory location. Signed-off-by: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Andrew Morton <akpm(a)linux-foundation.org> Cc: Christian Casteyde <casteyde.christian(a)free.fr> Cc: Pekka Enberg <penberg(a)cs.helsinki.fi> Cc: Vegard Nossum <vegardno(a)ifi.uio.no> --- arch/x86/mm/kmemcheck/kmemcheck.c | 2 +- arch/x86/mm/kmemcheck/shadow.c | 16 ++++++++++++++-- arch/x86/mm/kmemcheck/shadow.h | 2 ++ 3 files changed, 17 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/kmemcheck/kmemcheck.c b/arch/x86/mm/kmemcheck/kmemcheck.c index 8cc1833..b3b531a 100644 --- a/arch/x86/mm/kmemcheck/kmemcheck.c +++ b/arch/x86/mm/kmemcheck/kmemcheck.c @@ -337,7 +337,7 @@ bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size) if (!shadow) return true; - status = kmemcheck_shadow_test(shadow, size); + status = kmemcheck_shadow_test_all(shadow, size); return status == KMEMCHECK_SHADOW_INITIALIZED; } diff --git a/arch/x86/mm/kmemcheck/shadow.c b/arch/x86/mm/kmemcheck/shadow.c index 3f66b82..aec1242 100644 --- a/arch/x86/mm/kmemcheck/shadow.c +++ b/arch/x86/mm/kmemcheck/shadow.c @@ -125,12 +125,12 @@ void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n) enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size) { +#ifdef CONFIG_KMEMCHECK_PARTIAL_OK uint8_t *x; unsigned int i; x = shadow; -#ifdef CONFIG_KMEMCHECK_PARTIAL_OK /* * Make sure _some_ bytes are initialized. Gcc frequently generates * code to access neighboring bytes. @@ -139,13 +139,25 @@ enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size) if (x[i] == KMEMCHECK_SHADOW_INITIALIZED) return x[i]; } + + return x[0]; #else + return kmemcheck_shadow_test_all(shadow, size); +#endif +} + +enum kmemcheck_shadow kmemcheck_shadow_test_all(void *shadow, unsigned int size) +{ + uint8_t *x; + unsigned int i; + + x = shadow; + /* All bytes must be initialized. */ for (i = 0; i < size; ++i) { if (x[i] != KMEMCHECK_SHADOW_INITIALIZED) return x[i]; } -#endif return x[0]; } diff --git a/arch/x86/mm/kmemcheck/shadow.h b/arch/x86/mm/kmemcheck/shadow.h index af46d9a..ff0b2f7 100644 --- a/arch/x86/mm/kmemcheck/shadow.h +++ b/arch/x86/mm/kmemcheck/shadow.h @@ -11,6 +11,8 @@ enum kmemcheck_shadow { void *kmemcheck_shadow_lookup(unsigned long address); enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size); +enum kmemcheck_shadow kmemcheck_shadow_test_all(void *shadow, + unsigned int size); void kmemcheck_shadow_set(void *shadow, unsigned int size); #endif -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |