30 lines
933 B
Diff
30 lines
933 B
Diff
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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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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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Cc: stable-rt@vger.kernel.org
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---
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fs/timerfd.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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Index: linux-3.2/fs/timerfd.c
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===================================================================
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--- linux-3.2.orig/fs/timerfd.c
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+++ linux-3.2/fs/timerfd.c
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@@ -313,7 +313,7 @@ SYSCALL_DEFINE4(timerfd_settime, int, uf
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if (hrtimer_try_to_cancel(&ctx->tmr) >= 0)
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break;
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spin_unlock_irq(&ctx->wqh.lock);
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- cpu_relax();
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+ hrtimer_wait_for_timer(&ctx->tmr);
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}
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/*
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