* Patch "target: Fix missing complete during ABORT_TASK + CMD_T_FABRIC_STOP" has been added to the 4.4-stable tree
@ 2016-08-18 13:13 gregkh
0 siblings, 0 replies; only message in thread
From: gregkh @ 2016-08-18 13:13 UTC (permalink / raw)
To: nab, gregkh, hare, hch, himanshu.madhani, mchristi, quinn.tran
Cc: stable, stable-commits
This is a note to let you know that I've just added the patch titled
target: Fix missing complete during ABORT_TASK + CMD_T_FABRIC_STOP
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
target-fix-missing-complete-during-abort_task-cmd_t_fabric_stop.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From 5e2c956b8aa24d4f33ff7afef92d409eed164746 Mon Sep 17 00:00:00 2001
From: Nicholas Bellinger <nab@linux-iscsi.org>
Date: Wed, 25 May 2016 12:25:04 -0700
Subject: target: Fix missing complete during ABORT_TASK + CMD_T_FABRIC_STOP
From: Nicholas Bellinger <nab@linux-iscsi.org>
commit 5e2c956b8aa24d4f33ff7afef92d409eed164746 upstream.
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>
Tested-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/target/target_core_transport.c | 6 ------
1 file changed, 6 deletions(-)
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2541,12 +2541,6 @@ static void target_release_cmd_kref(stru
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);
Patches currently in stable-queue which might be from nab@linux-iscsi.org are
queue-4.4/target-fix-max_unmap_lba_count-calc-overflow.patch
queue-4.4/target-fix-ordered-task-check_condition-early-exception-handling.patch
queue-4.4/target-fix-race-between-iscsi-target-connection-shutdown-abort_task.patch
queue-4.4/target-fix-ordered-task-target_setup_cmd_from_cdb-exception-hang.patch
queue-4.4/iscsi-target-fix-panic-when-adding-second-tcp-connection-to-iscsi-session.patch
queue-4.4/target-fix-missing-complete-during-abort_task-cmd_t_fabric_stop.patch
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2016-08-18 13:13 Patch "target: Fix missing complete during ABORT_TASK + CMD_T_FABRIC_STOP" has been added to the 4.4-stable tree gregkh
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