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From:   Chris Wilson <chris@chris-wilson.co.uk>
To:     linux-kernel@vger.kernel.org
Cc:     Chris Wilson <chris@chris-wilson.co.uk>,
        Ingo Molnar <mingo@kernel.org>,
        Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH] khungtaskd: Kick stuck processes
Date:   Thu,  8 Feb 2018 19:07:53 +0000
Message-Id: <20180208190753.17690-1-chris@chris-wilson.co.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

After spotting a stuck process, and having decided not to panic, give
the task a kick to see if that helps it to recover (e.g. to paper over a
missed wake up).

References: https://bugs.freedesktop.org/show_bug.cgi?id=104009
References: https://bugs.freedesktop.org/show_bug.cgi?id=104682
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 kernel/hung_task.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 751593ed7c0b..b32acb6bcc63 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -132,6 +132,8 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
 		trigger_all_cpu_backtrace();
 		panic("hung_task: blocked tasks");
 	}
+
+	wake_up_process(t);
 }
 
 /*
-- 
2.16.1