32 lines
928 B
Diff
32 lines
928 B
Diff
Subject: timer-fd: Prevent live lock
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Wed, 25 Jan 2012 11:08:40 +0100
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.11/older/patches-4.11.5-rt1.tar.xz
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If hrtimer_try_to_cancel() requires a retry, then depending on the
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priority setting te retry loop might prevent timer callback completion
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on RT. Prevent that by waiting for completion on RT, no change for a
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non RT kernel.
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Reported-by: Sankara Muthukrishnan <sankara.m@gmail.com>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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fs/timerfd.c | 5 ++++-
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1 file changed, 4 insertions(+), 1 deletion(-)
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--- a/fs/timerfd.c
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+++ b/fs/timerfd.c
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@@ -471,7 +471,10 @@ static int do_timerfd_settime(int ufd, i
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break;
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}
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spin_unlock_irq(&ctx->wqh.lock);
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- cpu_relax();
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+ if (isalarm(ctx))
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+ hrtimer_wait_for_timer(&ctx->t.alarm.timer);
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+ else
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+ hrtimer_wait_for_timer(&ctx->t.tmr);
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}
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/*
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