On Thu, Oct 03, 2013 at 09:34:11AM -0700, Kees Cook wrote: > In dentry_string_cmp (via__d_lookup_rcu), when CONFIG_DCACHE_WORD_ACCESS > is set, word-width memory reads are performed. However, the string > allocation size may not be a multiple of the word size. To avoid reading > past the end of such an allocation, we must allocate in multiples of > the word size.
grep ^kmalloc /proc/slabinfo. Observe the suffix after "kmalloc-"... IOW, kmalloc() does round its argument up. Seeing that we allocate an external name only when allocation has to be longer than 32 bytes, the sucker is guaranteed to be at least a multiple of 32 by the time we pick the fitting cache (the worst case is when length is between 65 and 96; then we use kmalloc-96). When you start a port to a 512-bit architecture, you'll have much nastier problems than this one... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
