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authorSven Wegener <sven.wegener@stealer.net>2008-08-10 09:17:59 +0000
committerSven Wegener <sven.wegener@stealer.net>2008-08-11 11:45:40 +0200
commit8ab19ea36c5c5340ff598e4d15fc084eb65671dc (patch)
tree031f48201a1e3a07a22a8f6734d0bb1c806b2c28 /net/ipv4/ipvs/ip_vs_est.c
parentbc0fde2fad007a81ecffceb25a893a6c3f1ed767 (diff)
ipvs: Fix possible deadlock in estimator code
There is a slight chance for a deadlock in the estimator code. We can't call del_timer_sync() while holding our lock, as the timer might be active and spinning for the lock on another cpu. Work around this issue by using try_to_del_timer_sync() and releasing the lock. We could actually delete the timer outside of our lock, as the add and kill functions are only every called from userspace via [gs]etsockopt() and are serialized by a mutex, but better make this explicit. Signed-off-by: Sven Wegener <sven.wegener@stealer.net> Cc: stable <stable@kernel.org> Acked-by: Simon Horman <horms@verge.net.au>
Diffstat (limited to 'net/ipv4/ipvs/ip_vs_est.c')
-rw-r--r--net/ipv4/ipvs/ip_vs_est.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/net/ipv4/ipvs/ip_vs_est.c b/net/ipv4/ipvs/ip_vs_est.c
index bc04eedd6dbb..1d6e58e502fd 100644
--- a/net/ipv4/ipvs/ip_vs_est.c
+++ b/net/ipv4/ipvs/ip_vs_est.c
@@ -170,8 +170,11 @@ void ip_vs_kill_estimator(struct ip_vs_stats *stats)
kfree(est);
killed++;
}
- if (killed && est_list == NULL)
- del_timer_sync(&est_timer);
+ while (killed && !est_list && try_to_del_timer_sync(&est_timer) < 0) {
+ write_unlock_bh(&est_lock);
+ cpu_relax();
+ write_lock_bh(&est_lock);
+ }
write_unlock_bh(&est_lock);
}