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kmemcheck: Test the full object in kmemcheck_is_obj_initialized()

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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@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christian Casteyde <casteyde.christian@free.fr>
Cc: Vegard Nossum <vegardno@ifi.uio.no>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
This commit is contained in:
Catalin Marinas 2010-02-08 11:16:24 +00:00 committed by Pekka Enberg
parent 724e6d3fe8
commit 81fc03909a
3 changed files with 17 additions and 3 deletions
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2
arch/x86/mm/kmemcheck/kmemcheck.c
View file

@ -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;
}

16
arch/x86/mm/kmemcheck/shadow.c
View file

@ -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];
}

2
arch/x86/mm/kmemcheck/shadow.h
View file

@ -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