This is a note to let you know that I've just added the patch titled
RDMA/ib_srp: Fix a deadlock
to the 4.9-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:
rdma-ib_srp-fix-a-deadlock.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a0c4a7b02ff52c0b45ce94b73313fd8f5411470a
Author: Bart Van Assche <bvanassche@xxxxxxx>
Date: Tue Feb 15 13:05:11 2022 -0800
RDMA/ib_srp: Fix a deadlock
[ Upstream commit 081bdc9fe05bb23248f5effb6f811da3da4b8252 ]
Remove the flush_workqueue(system_long_wq) call since flushing
system_long_wq is deadlock-prone and since that call is redundant with a
preceding cancel_work_sync()
Link: https://lore.kernel.org/r/20220215210511.28303-3-bvanassche@xxxxxxx
Fixes: ef6c49d87c34 ("IB/srp: Eliminate state SRP_TARGET_DEAD")
Reported-by: syzbot+831661966588c802aae9@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Reviewed-by: Leon Romanovsky <leonro@xxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index af68be201c299..67b993f4ec91a 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -3646,9 +3646,11 @@ static void srp_remove_one(struct ib_device *device, void *client_data)
spin_unlock(&host->target_lock);
/*
- * Wait for tl_err and target port removal tasks.
+ * srp_queue_remove_work() queues a call to
+ * srp_remove_target(). The latter function cancels
+ * target->tl_err_work so waiting for the remove works to
+ * finish is sufficient.
*/
- flush_workqueue(system_long_wq);
flush_workqueue(srp_remove_wq);
kfree(host);
