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([2405:201:c052:b00b:5f40:1719:f321:a33e]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-3283da08e23sm1235905eec.29.2026.08.25.13.06.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Aug 2026 13:07:00 -0700 (PDT) From: pavankumaryalagada@gmail.com To: anna-maria@linutronix.de Cc: frederic@kernel.org, tglx@kernel.org, linux-kernel@vger.kernel.org, skhan@linuxfoundation.org, Yalagada Pavan Kumar , syzbot+143e0859898751aa8f94@syzkaller.appspotmail.com Subject: [PATCH] posix-timers: fix IRQ state handling in posix_timer_delete() Date: Wed, 26 Aug 2026 01:36:26 +0530 Message-ID: <20260825200626.139243-1-pavankumaryalagada@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Yalagada Pavan Kumar exit_itimers() uses a spinlock_irq guard for timer->it_lock, which maintains counted IRQ-disable state. However, posix_timer_delete() temporarily releases and reacquires the lock with spin_unlock_irq() and spin_lock_irq(), which do not maintain the same IRQ-disable state while timer_wait_running() may sleep. Use spin_unlock_irq_enable() and spin_lock_irq_disable() for the temporary lock handoff to keep the IRQ-disable state balanced. Reported-by: syzbot+143e0859898751aa8f94@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3D143e0859898751aa8f94 Tested-by: syzbot+143e0859898751aa8f94@syzkaller.appspotmail.com Signed-off-by: Yalagada Pavan Kumar --- kernel/time/posix-timers.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c index 436ba794cc0b..5e580b4223de 100644 --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -1057,9 +1057,9 @@ static void posix_timer_delete(struct k_itimer *timer) =20 while (timer->kclock->timer_del(timer) =3D=3D TIMER_RETRY) { guard(rcu)(); - spin_unlock_irq(&timer->it_lock); + spin_unlock_irq_enable(&timer->it_lock); timer_wait_running(timer); - spin_lock_irq(&timer->it_lock); + spin_lock_irq_disable(&timer->it_lock); } } =20 --=20 2.43.0