linux-kernel - [tip:timers/urgent] time: Revert to calling clock_was_set

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Message-ID: <tip-cab5e127eef040399902caa8e1510795583fa03a@git.kernel.org>
Date:	Fri, 28 Mar 2014 01:37:14 -0700
From:	tip-bot for John Stultz <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, john.stultz@...aro.org,
	hpa@...or.com, mingo@...nel.org, torvalds@...ux-foundation.org,
	tglx@...utronix.de
Subject: [tip:timers/urgent] time: Revert to calling clock_was_set_delayed
 () while in irq context

Commit-ID:  cab5e127eef040399902caa8e1510795583fa03a
Gitweb:     http://git.kernel.org/tip/cab5e127eef040399902caa8e1510795583fa03a
Author:     John Stultz <john.stultz@...aro.org>
AuthorDate: Thu, 27 Mar 2014 16:30:49 -0700
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Fri, 28 Mar 2014 08:07:07 +0100

time: Revert to calling clock_was_set_delayed() while in irq context

In commit 47a1b796306356f35 ("tick/timekeeping: Call
update_wall_time outside the jiffies lock"), we moved to calling
clock_was_set() due to the fact that we were no longer holding
the timekeeping or jiffies lock.

However, there is still the problem that clock_was_set()
triggers an IPI, which cannot be done from the timer's hard irq
context, and will generate WARN_ON warnings.

Apparently in my earlier testing, I'm guessing I didn't bump the
dmesg log level, so I somehow missed the WARN_ONs.

Thus we need to revert back to calling clock_was_set_delayed().

Signed-off-by: John Stultz <john.stultz@...aro.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Link: http://lkml.kernel.org/r/1395963049-11923-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 kernel/time/timekeeping.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 0aa4ce8..5b40279 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1435,7 +1435,8 @@ void update_wall_time(void)
 out:
 	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
 	if (clock_set)
-		clock_was_set();
+		/* Have to call _delayed version, since in irq context*/
+		clock_was_set_delayed();
 }
 
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