On 12/01/2014 04:59 AM, Julien Cristau wrote:
On Wed, Nov 26, 2014 at 12:20:03 +0530, Nikhil Mahale wrote:
From 5c797ce9cdb596107f9ebcdf8345ca234c587b22 Mon Sep 17 00:00:00 2001
From: Nikhil Mahale <[email protected]>
Date: Tue, 11 Nov 2014 17:44:28 +0530
Subject: [PATCH] os: Fix timer race conditions
Fixing following kind of race-conditions -
WaitForSomething()
|
----> // timers -> timer-1 -> timer-2 -> null
while (timers && (int) (timers->expires - now) <= 0)
// prototype - DoTimer(OsTimerPtr timer, CARD32 now, OsTimerPtr
*prev)
DoTimer(timers, now, &timers)
|
|
----> OsBlockSignals(); .... OS Signal comes just before
blocking it,
.... timer-1 handler gets called.
// timer-1 gets served and
scheduled again;
// timers -> timer-2 -> timer-1
-> null
....
*prev = timer->next;
timer->next = NULL; // timers -> null
// timers list gets corrupted here and timer-2 gets
removed from list.
https://bugs.freedesktop.org/show_bug.cgi?id=86288
Signed-off-by: Nikhil Mahale <[email protected]>
---
os/WaitFor.c | 31 ++++++++++++++++++++-----------
1 file changed, 20 insertions(+), 11 deletions(-)
Reviewed-by: Julien Cristau <[email protected]>
Keith, any chance of getting this in for 1.17? I know you expressed
reservations about it, but the current code definitely corrupts the
timer list and is affecting a bunch of people, so this patch is
certainly better than nothing.
-- Aaron
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