Messages in this thread | | | Date | Thu, 2 Apr 2009 14:39:32 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] - Fix slab corruption caused by alloc_cpumask_var_node() |
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On Thu, 2 Apr 2009 16:27:51 -0500 Jack Steiner <steiner@sgi.com> wrote:
> Fix for slab corruption caused by alloc_cpumask_var_node() overwriting > the tail end of an off-stack cpumask.
changelog is crappy.
> --- linux.orig/lib/cpumask.c 2009-04-02 15:30:05.000000000 -0500 > +++ linux/lib/cpumask.c 2009-04-02 15:57:44.000000000 -0500 > @@ -109,10 +109,10 @@ bool alloc_cpumask_var_node(cpumask_var_ > #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); > } >
It appears that the bug is that cpumask_bits() returns an `unsigned long *', except the pointer arithmetic in there is designed to operate on char*/void*/etc, correct?
This fix is needed in 2.6.29 as well, correct?
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