From: Chris Bainbridge <chris.bainbridge@gmail.com>
To: "Mateusz Jończyk" <mat.jonczyk@o2.pl>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
linux-rtc@vger.kernel.org,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
lkml <linux-kernel@vger.kernel.org>,
Anna-Maria Behnsen <anna-maria@linutronix.de>,
Frederic Weisbecker <frederic@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [DRAFT PATCH] rtc-cmos: use spin_lock_irqsave in cmos_interrupt
Date: Mon, 2 Jun 2025 22:19:22 +0100 [thread overview]
Message-ID: <aD4VWov2L1pJfxUY@debian.local> (raw)
In-Reply-To: <20250602202019.625331-1-mat.jonczyk@o2.pl>
On Mon, Jun 02, 2025 at 10:20:19PM +0200, Mateusz Jończyk wrote:
> cmos_interrupt() can also be called also in non-interrupt contexts, such
> as in ACPI handlers via rtc_handler(). Therefore, usage of
> spin_lock(&rtc_lock) is insecure. Use spin_lock_irqsave() / etc.
> instead.
>
> Remove the local_irq_disable() hacks in cmos_check_wkalrm() and add a
> comment so that these _irqsave / _irqrestore will not be disabled again,
> as in
>
> commit 6950d046eb6e ("rtc: cmos: Replace spin_lock_irqsave with spin_lock in hard IRQ")
>
> Untested yet.
>
> Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
> Fixes: 13be2efc390a ("rtc: cmos: Disable irq around direct invocation of cmos_interrupt()")
I tested this, and can confirm it does fix the "inconsistent lock state"
error in my test case.
next prev parent reply other threads:[~2025-06-02 21:19 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-30 11:32 [ BUG: Invalid wait context ] rtc_lock at: mc146818_avoid_UIP Borislav Petkov
2025-03-30 12:23 ` Mateusz Jończyk
2025-03-30 12:32 ` Mateusz Jończyk
2025-04-03 13:12 ` Thomas Gleixner
2025-04-03 13:50 ` Sebastian Andrzej Siewior
2025-04-03 19:36 ` Sebastian Andrzej Siewior
2025-04-03 20:26 ` Thomas Gleixner
2025-04-04 6:16 ` Sebastian Andrzej Siewior
2025-04-04 13:34 ` [PATCH] timekeeping: Add a lockdep override in tick_freeze() Sebastian Andrzej Siewior
2025-04-04 18:47 ` Mateusz Jończyk
2025-04-09 19:13 ` Peter Zijlstra
2025-04-09 21:12 ` [tip: timers/urgent] " tip-bot2 for Sebastian Andrzej Siewior
2025-05-31 18:27 ` [PATCH] " Chris Bainbridge
2025-05-31 19:16 ` Chris Bainbridge
2025-06-02 19:52 ` Mateusz Jończyk
2025-06-02 20:20 ` [DRAFT PATCH] rtc-cmos: use spin_lock_irqsave in cmos_interrupt Mateusz Jończyk
2025-06-02 21:19 ` Chris Bainbridge [this message]
2025-06-03 6:47 ` Sebastian Andrzej Siewior
2025-04-03 23:46 ` [ BUG: Invalid wait context ] rtc_lock at: mc146818_avoid_UIP Mateusz Jończyk
2025-04-04 7:39 ` Thomas Gleixner
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