From 081bdc9fe05bb23248f5effb6f811da3da4b8252 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bvanassche@acm.org>
Date: Tue, 15 Feb 2022 13:05:11 -0800
Subject: [PATCH 1/1] RDMA/ib_srp: Fix a deadlock
Git-commit: 081bdc9fe05bb23248f5effb6f811da3da4b8252
Patch-mainline: v5.17
References: git-fixes
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@acm.org
Fixes: ef6c49d87c34 ("IB/srp: Eliminate state SRP_TARGET_DEAD")
Reported-by: syzbot+831661966588c802aae9@syzkaller.appspotmail.com
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Nicolas Morey-Chaisemartin <nmoreychaisemartin@suse.com>
---
drivers/infiniband/ulp/srp/ib_srp.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index e174e853f8a4..285b766e4e70 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -4047,9 +4047,11 @@ 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);
--
2.35.0