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>
1 file changed