]> err.no Git - linux-2.6/commit
eCryptfs: use page_alloc not kmalloc to get a page of memory
authorEric Sandeen <sandeen@redhat.com>
Mon, 28 Jul 2008 22:46:39 +0000 (15:46 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Mon, 28 Jul 2008 23:30:21 +0000 (16:30 -0700)
commit7fcba054373d5dfc43d26e243a5c9b92069972ee
tree3503fba122a654946b5455bc95fa3978cbc4f68b
parent25947d5ac56004378d8c2d31ebf22600d5bc0c02
eCryptfs: use page_alloc not kmalloc to get a page of memory

With SLUB debugging turned on in 2.6.26, I was getting memory corruption
when testing eCryptfs.  The root cause turned out to be that eCryptfs was
doing kmalloc(PAGE_CACHE_SIZE); virt_to_page() and treating that as a nice
page-aligned chunk of memory.  But at least with SLUB debugging on, this
is not always true, and the page we get from virt_to_page does not
necessarily match the PAGE_CACHE_SIZE worth of memory we got from kmalloc.

My simple testcase was 2 loops doing "rm -f fileX; cp /tmp/fileX ." for 2
different multi-megabyte files.  With this change I no longer see the
corruption.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/ecryptfs/crypto.c