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| author | Roland Dreier <rolandd@cisco.com> | 2009-09-07 08:27:50 -0700 |
|---|---|---|
| committer | Roland Dreier <rolandd@cisco.com> | 2009-09-07 08:27:50 -0700 |
| commit | 6b2eef8fd78ff909c3396b8671d57c42559cc51d (patch) | |
| tree | 98557140c16bc825a82bfd414fedda46749dbbf7 /drivers/infiniband | |
| parent | 60f2b652f54aa4ac4127a538abad05235fb9c469 (diff) | |
| download | linux-6b2eef8fd78ff909c3396b8671d57c42559cc51d.tar.gz linux-6b2eef8fd78ff909c3396b8671d57c42559cc51d.tar.bz2 linux-6b2eef8fd78ff909c3396b8671d57c42559cc51d.zip | |
IB/mad: Fix possible lock-lock-timer deadlock
Lockdep reported a possible deadlock with cm_id_priv->lock,
mad_agent_priv->lock and mad_agent_priv->timed_work.timer; this
happens because the mad module does
cancel_delayed_work(&mad_agent_priv->timed_work);
while holding mad_agent_priv->lock. cancel_delayed_work() internally
does del_timer_sync(&mad_agent_priv->timed_work.timer).
This can turn into a deadlock because mad_agent_priv->lock is taken
inside cm_id_priv->lock, so we can get the following set of contexts
that deadlock each other:
A: holding cm_id_priv->lock, waiting for mad_agent_priv->lock
B: holding mad_agent_priv->lock, waiting for del_timer_sync()
C: interrupt during mad_agent_priv->timed_work.timer that takes
cm_id_priv->lock
Fix this by using the new __cancel_delayed_work() interface (which
internally does del_timer() instead of del_timer_sync()) in all the
places where we are holding a lock.
Addresses: http://bugzilla.kernel.org/show_bug.cgi?id=13757
Reported-by: Bart Van Assche <bart.vanassche@gmail.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Diffstat (limited to 'drivers/infiniband')
| -rw-r--r-- | drivers/infiniband/core/mad.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/infiniband/core/mad.c b/drivers/infiniband/core/mad.c index de922a04ca2d..bc30c00c5d7a 100644 --- a/drivers/infiniband/core/mad.c +++ b/drivers/infiniband/core/mad.c @@ -1974,7 +1974,7 @@ static void adjust_timeout(struct ib_mad_agent_private *mad_agent_priv) unsigned long delay; if (list_empty(&mad_agent_priv->wait_list)) { - cancel_delayed_work(&mad_agent_priv->timed_work); + __cancel_delayed_work(&mad_agent_priv->timed_work); } else { mad_send_wr = list_entry(mad_agent_priv->wait_list.next, struct ib_mad_send_wr_private, @@ -1983,7 +1983,7 @@ static void adjust_timeout(struct ib_mad_agent_private *mad_agent_priv) if (time_after(mad_agent_priv->timeout, mad_send_wr->timeout)) { mad_agent_priv->timeout = mad_send_wr->timeout; - cancel_delayed_work(&mad_agent_priv->timed_work); + __cancel_delayed_work(&mad_agent_priv->timed_work); delay = mad_send_wr->timeout - jiffies; if ((long)delay <= 0) delay = 1; @@ -2023,7 +2023,7 @@ static void wait_for_response(struct ib_mad_send_wr_private *mad_send_wr) /* Reschedule a work item if we have a shorter timeout */ if (mad_agent_priv->wait_list.next == &mad_send_wr->agent_list) { - cancel_delayed_work(&mad_agent_priv->timed_work); + __cancel_delayed_work(&mad_agent_priv->timed_work); queue_delayed_work(mad_agent_priv->qp_info->port_priv->wq, &mad_agent_priv->timed_work, delay); } |