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From: John Mathew <john.mathew@unikie.com>
To: bigeasy@linutronix.de
Cc: john.mathew@unikie.com, linux-rt-users@vger.kernel.org,
	lukas.bulwahn@gmail.com
Subject: [PATCH] swait: Increase number of waiters for warning
Date: Tue, 18 Feb 2020 09:18:57 +0200
Message-ID: <20200218071857.14805-1-john.mathew@unikie.com> (raw)
In-Reply-To: <20200213083121.vqbbbufja4uilblo@linutronix.de>

When stress testing the kernel using the syzkaller the following
warning occurs frequently:

[ 553.403826] 001: complete_all() with 4 waiters
[ 553.404205] 001: WARNING: CPU: 1 PID: 10418 at swake_up_all_locked+0x146/0x1e0
[ 553.404806] 001: Modules linked in:
[ 553.405101] 001:
[ 553.405269] 001: CPU: 1 PID: 10418 Comm: cryptomgr_probe Tainted: G

Investigation shows that this warning is caused due to the mode
of working of the crypto module using completions. The increased number
was found through experimentaion using syzkaller.

Signed-off-by: John Mathew <john.mathew@unikie.com>
---
 kernel/sched/swait.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c
index c58068d2ee06..111f9bc98e4d 100644
--- a/kernel/sched/swait.c
+++ b/kernel/sched/swait.c
@@ -47,7 +47,7 @@ void swake_up_all_locked(struct swait_queue_head *q)
 	}
 	if (pm_in_action)
 		return;
-	WARN(wakes > 2, "complete_all() with %d waiters\n", wakes);
+	WARN(wakes > 10, "complete_all() with %d waiters\n", wakes);
 }
 EXPORT_SYMBOL(swake_up_all_locked);
 
-- 
2.17.1


  reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-11  7:17 complete_all() with x waiters in swake_up_all_locked John Mathew
2019-12-12 17:12 ` Sebastian Andrzej Siewior
2019-12-13  9:08   ` John Mathew
2019-12-18 16:53     ` Sebastian Andrzej Siewior
2019-12-31 10:00       ` [PATCH] crypto: only wait for completion once John Mathew
2020-01-14 12:47         ` Sebastian Andrzej Siewior
2020-02-11 11:48           ` John Mathew
2020-02-11 12:04             ` Sebastian Andrzej Siewior
2020-02-11 15:52               ` John Mathew
2020-02-11 15:59                 ` Sebastian Andrzej Siewior
2020-02-12 12:55                   ` John Mathew
2020-02-12 17:02                     ` Sebastian Andrzej Siewior
2020-02-13  6:58                       ` John Mathew
2020-02-13  8:31                         ` Sebastian Andrzej Siewior
2020-02-18  7:18                           ` John Mathew [this message]
2020-03-20 16:54                             ` [PATCH RT] swait: Remove the warning with more than two waiters Sebastian Andrzej Siewior

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