| From | Ben Hutchings <> | Date | Mon, 09 Oct 2017 13:44:24 +0100 | Subject | [PATCH 3.16 096/192] target: Fix COMPARE_AND_WRITE caw_sem leak during se_cmd quiesce |
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3.16.49-rc1 review patch. If anyone has any objections, please let me know.
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From: Jiang Yi <jiangyilism@gmail.com>
commit 1d6ef276594a781686058802996e09c8550fd767 upstream.
This patch addresses a COMPARE_AND_WRITE se_device->caw_sem leak, that would be triggered during normal se_cmd shutdown or abort via __transport_wait_for_tasks().
This would occur because target_complete_cmd() would catch this early and do complete_all(&cmd->t_transport_stop_comp), but since target_complete_ok_work() or target_complete_failure_work() are never called to invoke se_cmd->transport_complete_callback(), the COMPARE_AND_WRITE specific callbacks never release caw_sem.
To address this special case, go ahead and release caw_sem directly from target_complete_cmd().
(Remove '&& success' from check, to release caw_sem regardless of scsi_status - nab)
Signed-off-by: Jiang Yi <jiangyilism@gmail.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/target/target_core_transport.c | 9 +++++++++ 1 file changed, 9 insertions(+)
--- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -689,6 +689,15 @@ void target_complete_cmd(struct se_cmd * if (cmd->transport_state & CMD_T_ABORTED || cmd->transport_state & CMD_T_STOP) { spin_unlock_irqrestore(&cmd->t_state_lock, flags); + /* + * If COMPARE_AND_WRITE was stopped by __transport_wait_for_tasks(), + * release se_device->caw_sem obtained by sbc_compare_and_write() + * since target_complete_ok_work() or target_complete_failure_work() + * won't be called to invoke the normal CAW completion callbacks. + */ + if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) { + up(&dev->caw_sem); + } complete_all(&cmd->t_transport_stop_comp); return; } else if (!success) {
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