fs: dcache: manually unpoison dname after allocation to shut up kasan's reports
authorAndrey Ryabinin <a.ryabinin@samsung.com>
Fri, 13 Feb 2015 22:39:45 +0000 (14:39 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 14 Feb 2015 05:21:41 +0000 (21:21 -0800)
commitdf4c0e36f1b1782b0611a77c52cc240e5c4752dd
tree1cdb9be1182864d4604200bf58f044673fa85843
parent0316bec22ec95ea2faca6406437b0b5950553b7c
fs: dcache: manually unpoison dname after allocation to shut up kasan's reports

We need to manually unpoison rounded up allocation size for dname to avoid
kasan's reports in dentry_string_cmp().  When CONFIG_DCACHE_WORD_ACCESS=y
dentry_string_cmp may access few bytes beyound requested in kmalloc()
size.

dentry_string_cmp() relates on that fact that dentry allocated using
kmalloc and kmalloc internally round up allocation size.  So this is not a
bug, but this makes kasan to complain about such accesses.  To avoid such
reports we mark rounded up allocation size in shadow as accessible.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/dcache.c