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| author | Sven Wegener <sven.wegener@stealer.net> | 2008-08-14 03:55:22 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-08-20 11:15:26 -0700 |
| commit | 1cc2f16f28ccfc4c0b477e3b0de7b89817876938 (patch) | |
| tree | 0a252faed7300d25cf59e48b2559f2654a3e461f /net | |
| parent | b50504f77c63d836cd2ed62d3e675353970b4d58 (diff) | |
| download | lwn-1cc2f16f28ccfc4c0b477e3b0de7b89817876938.tar.gz lwn-1cc2f16f28ccfc4c0b477e3b0de7b89817876938.zip | |
ipvs: Fix possible deadlock in estimator code
commit 8ab19ea36c5c5340ff598e4d15fc084eb65671dc upstream
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>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'net')
| -rw-r--r-- | 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 dfa0d713c801..f97ffc5a6b8a 100644 --- a/net/ipv4/ipvs/ip_vs_est.c +++ b/net/ipv4/ipvs/ip_vs_est.c @@ -172,8 +172,11 @@ 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); } |