[PATCH 09/11] net: Clean up sk_wait_event() vs might_sleep()

From: Peter Zijlstra
Date: Wed Sep 24 2014 - 04:30:01 EST

WARNING: CPU: 1 PID: 1744 at kernel/sched/core.c:7104 __might_sleep+0x58/0x90()
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff81070e10>] prepare_to_wait+0x50 /0xa0

[<ffffffff8105bc38>] __might_sleep+0x58/0x90
[<ffffffff8148c671>] lock_sock_nested+0x31/0xb0
[<ffffffff81498aaa>] sk_stream_wait_memory+0x18a/0x2d0

Which is a false positive because sk_wait_event() will already have
TASK_RUNNING at that point if it would've gone through

So annotate with fixup_sleep(); which goes away on !DEBUG builds.

Cc: netdev@xxxxxxxxxxxxxxx
Cc: David Miller <davem@xxxxxxxxxxxxx>
Reported-by: Ilya Dryomov <ilya.dryomov@xxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
include/net/sock.h | 1 +
1 file changed, 1 insertion(+)

--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -902,6 +902,7 @@ static inline void sock_rps_reset_rxhash
if (!__rc) { \
*(__timeo) = schedule_timeout(*(__timeo)); \
} \
+ fixup_sleep(); \
lock_sock(__sk); \
__rc = __condition; \
__rc; \

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