[2.6.20.17 review 04/58] gen estimator timer unload race

Willy Tarreau
2007-08-22T08:53:31Z

[-- Attachment #1: 0004-gen-estimator-timer-unload-race.patch --]
[-- Type: text/plain, Size: 1059 bytes --]

[NET]: Fix gen_estimator timer removal race

As noticed by Jarek Poplawski <jarkao2@o2.pl>, the timer removal in
gen_kill_estimator races with the timer function rearming the timer.

Check whether the timer list is empty before rearming the timer
in the timer function to fix this.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Jarek Poplawski <jarkao2@o2.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
net/core/gen_estimator.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
index 3cad026..33d82bf 100644
--- a/net/core/gen_estimator.c
+++ b/net/core/gen_estimator.c
@@ -128,7 +128,8 @@ static void est_timer(unsigned long arg)
spin_unlock(e->stats_lock);
}

- mod_timer(&elist[idx].timer, jiffies + ((HZ<<idx)/4));
+ if (elist[idx].list != NULL)
+ mod_timer(&elist[idx].timer, jiffies + ((HZ<<idx)/4));
read_unlock(&est_lock);
}

--
1.5.2.5

--