From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Karl Mehltretter <kmehltretter@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>,
Arnd Bergmann <arnd@arndb.de>,
linux-rt-devel@lists.linux.dev,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ARM: select HAVE_POSIX_CPU_TIMERS_TASK_WORK
Date: Mon, 20 Jul 2026 09:26:06 +0200 [thread overview]
Message-ID: <20260720072606.8KxzuDAj@linutronix.de> (raw)
In-Reply-To: <20260718214515.11275-1-kmehltretter@gmail.com>
On 2026-07-18 23:45:15 [+0200], Karl Mehltretter wrote:
> Commit c6e61c06d606 ("ARM: 9463/1: Allow to enable RT") enabled PREEMPT_RT
> on ARM but did not select HAVE_POSIX_CPU_TIMERS_TASK_WORK. This leaves
> CONFIG_POSIX_CPU_TIMERS_TASK_WORK disabled, so CPU timers expire in hard
> IRQ context.
…
> Fixes: c6e61c06d606 ("ARM: 9463/1: Allow to enable RT")
> Assisted-by: Claude:claude-fable-5
> Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Found with a self-hosted syzkaller instance patched to fuzz kernels on
> QEMU's versatilepb machine (ARM926EJ-S, ARMv5TE). Runtime-tested before
> and after the change on that setup, and compile-tested mps2_defconfig
> with PREEMPT_RT (NOMMU, CPU_V7M).
I obviously got the rules confused while dropping the KVM patches.
Sebastian
prev parent reply other threads:[~2026-07-20 7:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-18 21:45 [PATCH] ARM: select HAVE_POSIX_CPU_TIMERS_TASK_WORK Karl Mehltretter
2026-07-19 16:15 ` Arnd Bergmann
2026-07-20 7:26 ` Sebastian Andrzej Siewior [this message]
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