[PATCH 5.8 330/633] RDMA/ucma: Add missing locking around rdma_leave_multicast()

[Greg Kroah-Hartman]

From: Jason Gunthorpe <jgg@xxxxxxxxxx>

[ Upstream commit 38e03d092699891c3237b5aee9e8029d4ede0956 ]

All entry points to the rdma_cm from a ULP must be single threaded,
even this error unwinds. Add the missing locking.

Fixes: 7c11910783a1 ("RDMA/ucma: Put a lock around every call to the rdma_cm layer")
Link: https://lore.kernel.org/r/20200818120526.702120-11-leon@xxxxxxxxxx
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/infiniband/core/ucma.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index cf283b70bf877..2643d5dbe1da8 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -1512,7 +1512,9 @@ static ssize_t ucma_process_join(struct ucma_file *file,
 	return 0;
 
 err3:
+	mutex_lock(&ctx->mutex);
 	rdma_leave_multicast(ctx->cm_id, (struct sockaddr *) &mc->addr);
+	mutex_unlock(&ctx->mutex);
 	ucma_cleanup_mc_events(mc);
 err2:
 	xa_erase(&multicast_table, mc->id);
-- 
2.25.1