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Message-ID: <20210819193030.zpwrpvvrmy7xxxiy@linutronix.de>
Date: Thu, 19 Aug 2021 21:30:30 +0200
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>,
LKML <linux-kernel@...r.kernel.org>,
Ingo Molnar <mingo@...nel.org>,
Juri Lelli <juri.lelli@...hat.com>,
Steven Rostedt <rostedt@...dmis.org>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
Will Deacon <will@...nel.org>,
Waiman Long <longman@...hat.com>,
Boqun Feng <boqun.feng@...il.com>,
Davidlohr Bueso <dave@...olabs.net>,
Mike Galbraith <efault@....de>,
Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH v2] locking/ww_mutex: Initialize waiter.ww_ctx properly
The gathering of the debug code for the ww-mutex initialized moved the
POISON initialiation into one spot and only set waiter.ww_ctx if the
ww_ctx was non-NULL thus keeping the POISON value in ww-mutex case.
For ww-mutex without a context it is expected to set the context to
NULL, the poison value was intended only for the regular mutex.
Always initialized waiter.ww_ctx to ww_ctx in the ww-mutex case.
Fixes: c0afb0ffc06e6 ("locking/ww_mutex: Gather mutex_waiter initialization")
Reported-by: Guenter Roeck <linux@...ck-us.net>
Suggested-by: Peter Zijlstra <peterz@...radead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
v1…v2: Use PeterZ' approach.
kernel/locking/mutex.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 05b68931622d1..2c70213934cd4 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -614,7 +614,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
debug_mutex_lock_common(lock, &waiter);
waiter.task = current;
- if (ww_ctx)
+ if (use_ww_ctx)
waiter.ww_ctx = ww_ctx;
lock_contended(&lock->dep_map, ip);
--
2.33.0
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