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

From: Willy Tarreau
Date: Wed Aug 22 2007 - 04:53:32 EST


[NET]: Fix gen_estimator timer removal race

As noticed by Jarek Poplawski <jarkao2@xxxxx>, 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@xxxxxxxxx>
Acked-by: Jarek Poplawski <jarkao2@xxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
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

--
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