From: Anna-Maria Behnsen <anna-maria@linutronix.de>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linuxfoundation.org>,
Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <peterz@infradead.org>,
Stephen Boyd <sboyd@kernel.org>,
Guenter Roeck <linux@roeck-us.net>,
Andrew Morton <akpm@linux-foundation.org>,
Julia Lawall <Julia.Lawall@inria.fr>,
Arnd Bergmann <arnd@arndb.de>,
Viresh Kumar <viresh.kumar@linaro.org>,
Marc Zyngier <maz@kernel.org>,
Marcel Holtmann <marcel@holtmann.org>,
Johan Hedberg <johan.hedberg@gmail.com>,
Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
linux-bluetooth@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
netdev@vger.kernel.org, Jacob Keller <jacob.e.keller@intel.com>
Subject: Re: [patch V3 17/17] Bluetooth: hci_qca: Fix the teardown problem for real
Date: Thu, 24 Nov 2022 14:56:35 +0100 (CET) [thread overview]
Message-ID: <21108e77-f67d-528-dd61-249c5ebe217f@linutronix.de> (raw)
In-Reply-To: <20221123201625.435907114@linutronix.de>
On Wed, 23 Nov 2022, Thomas Gleixner wrote:
> While discussing solutions for the teardown problem which results from
> circular dependencies between timers and workqueues, where timers schedule
> work from their timer callback and workqueues arm the timers from work
> items, it was discovered that the recent fix to the QCA code is incorrect.
>
> That commit fixes the obvious problem of using del_timer() instead of
> del_timer_sync() and reorders the teardown calls to
>
> destroy_workqueue(wq);
> del_timer_sync(t);
>
> This makes it less likely to explode, but it's still broken:
>
> destroy_workqueue(wq);
> /* After this point @wq cannot be touched anymore */
>
> ---> timer expires
> queue_work(wq) <---- Results in a NULl pointer dereference
The last NIT (for now...): s/NULl/NULL
Thanks,
Anna-Maria
next prev parent reply other threads:[~2022-11-24 13:57 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-23 20:18 [patch V3 00/17] timers: Provide timer_shutdown[_sync]() Thomas Gleixner
2022-11-23 20:18 ` [patch V3 01/17] Documentation: Remove bogus claim about del_timer_sync() Thomas Gleixner
2022-11-24 14:16 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2022-11-23 20:18 ` [patch V3 02/17] ARM: spear: Do not use timer namespace for timer_shutdown() function Thomas Gleixner
2022-11-23 20:18 ` [patch V3 03/17] clocksource/drivers/arm_arch_timer: " Thomas Gleixner
2022-11-23 20:18 ` [patch V3 04/17] clocksource/drivers/sp804: " Thomas Gleixner
2022-11-23 20:18 ` [patch V3 05/17] timers: Get rid of del_singleshot_timer_sync() Thomas Gleixner
2022-11-24 14:16 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2022-11-23 20:18 ` [patch V3 06/17] timers: Replace BUG_ON()s Thomas Gleixner
2022-11-24 14:16 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2022-11-23 20:18 ` [patch V3 07/17] timers: Update kernel-doc for various functions Thomas Gleixner
2022-11-24 14:16 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2022-11-23 20:18 ` [patch V3 08/17] timers: Use del_timer_sync() even on UP Thomas Gleixner
2022-11-23 20:18 ` [patch V3 09/17] timers: Rename del_timer_sync() to timer_delete_sync() Thomas Gleixner
2022-11-24 14:16 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2022-11-23 20:18 ` [patch V3 10/17] timers: Rename del_timer() to timer_delete() Thomas Gleixner
2022-11-24 14:16 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2022-11-23 20:18 ` [patch V3 11/17] Documentation: Replace del_timer/del_timer_sync() Thomas Gleixner
2022-11-24 14:16 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2022-11-23 20:18 ` [patch V3 12/17] timers: Silently ignore timers with a NULL function Thomas Gleixner
2022-11-24 7:37 ` Anna-Maria Behnsen
2022-11-24 8:18 ` Thomas Gleixner
2022-11-24 8:22 ` [patch V3.1 " Thomas Gleixner
2022-11-23 20:18 ` [patch V3 13/17] timers: Split [try_to_]del_timer[_sync]() to prepare for shutdown mode Thomas Gleixner
2022-11-23 20:18 ` [patch V3 14/17] timers: Add shutdown mechanism to the internal functions Thomas Gleixner
2022-11-24 13:48 ` Anna-Maria Behnsen
2022-11-23 20:18 ` [patch V3 15/17] timers: Provide timer_shutdown[_sync]() Thomas Gleixner
2022-11-23 20:18 ` [patch V3 16/17] timers: Update the documentation to reflect on the new timer_shutdown() API Thomas Gleixner
2022-11-23 20:18 ` [patch V3 17/17] Bluetooth: hci_qca: Fix the teardown problem for real Thomas Gleixner
2022-11-24 13:56 ` Anna-Maria Behnsen [this message]
2022-11-24 14:00 ` [patch V3 00/17] timers: Provide timer_shutdown[_sync]() Anna-Maria Behnsen
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