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From: Sven Wegener <sven.wegener@xxxxxxxxxxx>
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@xxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxx>
---
net/ipv4/ipvs/ip_vs_est.c | 7 +++++--
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 bc04eed..1d6e58e 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);
}
--
1.5.6.4
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