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| author | Jack Steiner <steiner@sgi.com> | 2009-04-02 16:59:48 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-02 19:05:11 -0700 |
| commit | 4f032ac4122a77dbabf7a24b2739b2790448180f (patch) | |
| tree | 6a56afe2e32f346f2d24ac592a7cfdd0263c1629 /lib | |
| parent | 2d09cde985702503970d7cc18d762fae17e1cf88 (diff) | |
| download | lwn-4f032ac4122a77dbabf7a24b2739b2790448180f.tar.gz lwn-4f032ac4122a77dbabf7a24b2739b2790448180f.zip | |
cpumask: fix slab corruption caused by alloc_cpumask_var_node()
Fix slab corruption caused by alloc_cpumask_var_node() overwriting the
tail end of an off-stack cpumask.
The function zeros out cpumask bits beyond the last possible cpu. The
starting point for zeroing should be the beginning of the mask offset by a
byte count derived from the number of possible cpus. The offset was
calculated in bits instead of bytes. This resulted in overwriting the end
of the cpumask.
Signed-off-by: Jack Steiner <steiner@sgi.com>
Acked-by: Mike Travis <travis.sgi.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: <stable@kernel.org> [2.6.29.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/cpumask.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/lib/cpumask.c b/lib/cpumask.c index 3389e2440da0..1f71b97de0f9 100644 --- a/lib/cpumask.c +++ b/lib/cpumask.c @@ -109,10 +109,10 @@ bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node) #endif /* FIXME: Bandaid to save us from old primitives which go to NR_CPUS. */ if (*mask) { + unsigned char *ptr = (unsigned char *)cpumask_bits(*mask); unsigned int tail; tail = BITS_TO_LONGS(NR_CPUS - nr_cpumask_bits) * sizeof(long); - memset(cpumask_bits(*mask) + cpumask_size() - tail, - 0, tail); + memset(ptr + cpumask_size() - tail, 0, tail); } return *mask != NULL; |