From ccf5ae83a6cf3d9cfe9a7038bfe7cd38ab03d5e1 Mon Sep 17 00:00:00 2001 From: Joern Engel Date: Mon, 13 May 2013 16:30:06 -0400 Subject: target: close target_put_sess_cmd() vs. core_tmr_abort_task() race It is possible for one thread to to take se_sess->sess_cmd_lock in core_tmr_abort_task() before taking a reference count on se_cmd->cmd_kref, while another thread in target_put_sess_cmd() drops se_cmd->cmd_kref before taking se_sess->sess_cmd_lock. This introduces kref_put_spinlock_irqsave() and uses it in target_put_sess_cmd() to close the race window. Signed-off-by: Joern Engel Acked-by: Greg Kroah-Hartman Cc: Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_transport.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'drivers/target') diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index c3477fa60942..4a793362309d 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -2211,21 +2211,19 @@ static void target_release_cmd_kref(struct kref *kref) { struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref); struct se_session *se_sess = se_cmd->se_sess; - unsigned long flags; - spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); if (list_empty(&se_cmd->se_cmd_list)) { - spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + spin_unlock(&se_sess->sess_cmd_lock); se_cmd->se_tfo->release_cmd(se_cmd); return; } if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) { - spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + spin_unlock(&se_sess->sess_cmd_lock); complete(&se_cmd->cmd_wait_comp); return; } list_del(&se_cmd->se_cmd_list); - spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + spin_unlock(&se_sess->sess_cmd_lock); se_cmd->se_tfo->release_cmd(se_cmd); } @@ -2236,7 +2234,8 @@ static void target_release_cmd_kref(struct kref *kref) */ int target_put_sess_cmd(struct se_session *se_sess, struct se_cmd *se_cmd) { - return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref); + return kref_put_spinlock_irqsave(&se_cmd->cmd_kref, target_release_cmd_kref, + &se_sess->sess_cmd_lock); } EXPORT_SYMBOL(target_put_sess_cmd); -- cgit v1.2.3