linux/fs/f2fs
David Miller d41519a69b crypto: Work around deallocated stack frame reference gcc bug on sparc.
On sparc, if we have an alloca() like situation, as is the case with
SHASH_DESC_ON_STACK(), we can end up referencing deallocated stack
memory.  The result can be that the value is clobbered if a trap
or interrupt arrives at just the right instruction.

It only occurs if the function ends returning a value from that
alloca() area and that value can be placed into the return value
register using a single instruction.

For example, in lib/libcrc32c.c:crc32c() we end up with a return
sequence like:

        return  %i7+8
         lduw   [%o5+16], %o0   ! MEM[(u32 *)__shash_desc.1_10 + 16B],

%o5 holds the base of the on-stack area allocated for the shash
descriptor.  But the return released the stack frame and the
register window.

So if an intererupt arrives between 'return' and 'lduw', then
the value read at %o5+16 can be corrupted.

Add a data compiler barrier to work around this problem.  This is
exactly what the gcc fix will end up doing as well, and it absolutely
should not change the code generated for other cpus (unless gcc
on them has the same bug :-)

With crucial insight from Eric Sandeen.

Cc: <stable@vger.kernel.org>
Reported-by: Anatoly Pugachev <matorola@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-06-08 17:36:03 +08:00
..
Kconfig f2fs: add mount option to select fault injection ratio 2016-05-07 10:32:22 -07:00
Makefile fs crypto: move per-file encryption from f2fs tree to fs/crypto 2016-03-17 21:19:33 -07:00
acl.c f2fs: keep dirty inodes selectively for checkpoint 2016-11-23 12:11:08 -08:00
acl.h f2fs: remove dead code f2fs_check_acl 2016-09-14 16:52:36 -07:00
checkpoint.c f2fs: introduce CP_TRIMMED_FLAG to avoid unneeded discard 2017-05-03 10:04:56 -07:00
data.c f2fs: Make flush bios explicitely sync 2017-05-03 14:30:18 -07:00
debug.c f2fs: show available_nids in f2fs/status 2017-05-03 10:04:57 -07:00
dir.c for-f2fs-4.12 2017-05-08 12:24:17 -07:00
extent_cache.c f2fs: introduce __check_rb_tree_consistence 2017-04-19 11:00:44 -07:00
f2fs.h crypto: Work around deallocated stack frame reference gcc bug on sparc. 2017-06-08 17:36:03 +08:00
file.c Merge branch 'akpm' (patches from Andrew) 2017-05-08 18:17:56 -07:00
gc.c f2fs: release cp and dnode lock before IPU 2017-05-03 10:04:54 -07:00
gc.h f2fs: detect idle time depending on user behavior 2016-01-11 15:56:37 -08:00
hash.c f2fs: check entire encrypted bigname when finding a dentry 2017-05-04 11:44:35 -04:00
inline.c for-f2fs-4.12 2017-05-08 12:24:17 -07:00
inode.c f2fs: fix out-of free segments 2017-04-24 13:13:23 -07:00
namei.c for-f2fs-4.12 2017-05-08 12:24:17 -07:00
node.c Merge branch 'akpm' (patches from Andrew) 2017-05-08 18:17:56 -07:00
node.h f2fs: guard macro variables with braces 2017-04-10 19:48:10 -07:00
recovery.c f2fs: avoid dirty node pages in check_only recovery 2017-04-18 13:37:49 -07:00
segment.c Merge branch 'akpm' (patches from Andrew) 2017-05-08 18:17:56 -07:00
segment.h Merge branch 'akpm' (patches from Andrew) 2017-05-08 18:17:56 -07:00
shrinker.c f2fs: avoid casted negative value as shrink count 2016-11-23 12:11:03 -08:00
super.c f2fs: Make flush bios explicitely sync 2017-05-03 14:30:18 -07:00
trace.c f2fs: use set_page_private marcro in f2fs_trace_pid 2017-03-24 15:10:49 -04:00
trace.h f2fs: add sbi and page pointer in f2fs_io_info 2015-05-28 15:41:32 -07:00
xattr.c f2fs: don't reserve additional space in xattr block 2017-03-24 15:10:53 -04:00
xattr.h f2fs: guard macro variables with braces 2017-04-10 19:48:10 -07:00