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| author | Sasha Levin <sasha.levin@oracle.com> | 2013-06-10 23:18:00 +0400 |
|---|---|---|
| committer | Pekka Enberg <penberg@kernel.org> | 2013-06-13 11:01:58 +0400 |
| commit | 907985f48bc60818e291c631249f9bc84c83a06f (patch) | |
| tree | bec7068ac2fa689cfb56e06bcc6abf8543095364 | |
| parent | 317ddd256b9c24b0d78fa8018f80f1e495481a10 (diff) | |
| download | linux-907985f48bc60818e291c631249f9bc84c83a06f.tar.xz | |
slab: prevent warnings when allocating with __GFP_NOWARN
Sasha Levin noticed that the warning introduced by commit 6286ae9
("slab: Return NULL for oversized allocations) is being triggered:
WARNING: CPU: 15 PID: 21519 at mm/slab_common.c:376 kmalloc_slab+0x2f/0xb0()
can: request_module (can-proto-4) failed.
mpoa: proc_mpc_write: could not parse ''
Modules linked in:
CPU: 15 PID: 21519 Comm: trinity-child15 Tainted: G W 3.10.0-rc4-next-20130607-sasha-00011-gcd78395-dirty #2
0000000000000009 ffff880020a95e30 ffffffff83ff4041 0000000000000000
ffff880020a95e68 ffffffff8111fe12 fffffffffffffff0 00000000000082d0
0000000000080000 0000000000080000 0000000001400000 ffff880020a95e78
Call Trace:
[<ffffffff83ff4041>] dump_stack+0x4e/0x82
[<ffffffff8111fe12>] warn_slowpath_common+0x82/0xb0
[<ffffffff8111fe55>] warn_slowpath_null+0x15/0x20
[<ffffffff81243dcf>] kmalloc_slab+0x2f/0xb0
[<ffffffff81278d54>] __kmalloc+0x24/0x4b0
[<ffffffff8196ffe3>] ? security_capable+0x13/0x20
[<ffffffff812a26b7>] ? pipe_fcntl+0x107/0x210
[<ffffffff812a26b7>] pipe_fcntl+0x107/0x210
[<ffffffff812b7ea0>] ? fget_raw_light+0x130/0x3f0
[<ffffffff812aa5fb>] SyS_fcntl+0x60b/0x6a0
[<ffffffff8403ca98>] tracesys+0xe1/0xe6
Andrew Morton writes:
__GFP_NOWARN is frequently used by kernel code to probe for "how big
an allocation can I get". That's a bit lame, but it's used on slow
paths and is pretty simple.
However, SLAB would still spew a warning when a big allocation happens
if the __GFP_NOWARN flag is _not_ set to expose kernel bugs.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
[ penberg@kernel.org: improve changelog ]
Signed-off-by: Pekka Enberg <penberg@kernel.org>
| -rw-r--r-- | mm/slab_common.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c index ff3218a0f5e1..2d414508e9ec 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -373,8 +373,10 @@ struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags) { int index; - if (WARN_ON_ONCE(size > KMALLOC_MAX_SIZE)) + if (size > KMALLOC_MAX_SIZE) { + WARN_ON_ONCE(!(flags & __GFP_NOWARN)); return NULL; + } if (size <= 192) { if (!size) |