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authorNicholas Bellinger <nab@linux-iscsi.org>2016-05-25 12:25:04 -0700
committerNicholas Bellinger <nab@linux-iscsi.org>2016-07-20 00:58:26 -0700
commit5e2c956b8aa24d4f33ff7afef92d409eed164746 (patch)
treee25c73ebad987a4b4c1e9c6737212b37e2710ad3 /drivers/target
parentaf8c34ce6ae32addda3788d54a7e340cad22516b (diff)
downloadblackbird-op-linux-5e2c956b8aa24d4f33ff7afef92d409eed164746.tar.gz
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target: Fix missing complete during ABORT_TASK + CMD_T_FABRIC_STOP
During transport_generic_free_cmd() with a concurrent TMR ABORT_TASK and shutdown CMD_T_FABRIC_STOP bit set, the caller will be blocked on se_cmd->cmd_wait_stop completion until the final kref_put() -> target_release_cmd_kref() has been invoked to call complete(). However, when ABORT_TASK is completed with FUNCTION_COMPLETE in core_tmr_abort_task(), the aborted se_cmd will have already been removed from se_sess->sess_cmd_list via list_del_init(). This results in target_release_cmd_kref() hitting the legacy list_empty() == true check, invoking ->release_cmd() but skipping complete() to wakeup se_cmd->cmd_wait_stop blocked earlier in transport_generic_free_cmd() code. To address this bug, it's safe to go ahead and drop the original list_empty() check so that fabric_stop invokes the complete() as expected, since list_del_init() can safely be used on a empty list. Cc: Mike Christie <mchristi@redhat.com> Cc: Quinn Tran <quinn.tran@qlogic.com> Cc: Himanshu Madhani <himanshu.madhani@qlogic.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: stable@vger.kernel.org # 3.14+ Tested-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/target_core_transport.c6
1 files changed, 0 insertions, 6 deletions
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 5ab3967dda43..ae97e81141ed 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2557,12 +2557,6 @@ static void target_release_cmd_kref(struct kref *kref)
bool fabric_stop;
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);
- target_free_cmd_mem(se_cmd);
- se_cmd->se_tfo->release_cmd(se_cmd);
- return;
- }
spin_lock(&se_cmd->t_state_lock);
fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP);
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