This is a note to let you know that I've just added the patch titled RDMA/ucma: Add missing locking around rdma_leave_multicast() to the 5.4-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: rdma-ucma-add-missing-locking-around-rdma_leave_mult.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 0b706f5adaadd777d5db0ee5f829faf9f53b8f93 Author: Jason Gunthorpe <jgg@xxxxxxxxxx> Date: Tue Aug 18 15:05:22 2020 +0300 RDMA/ucma: Add missing locking around rdma_leave_multicast() [ 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> diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c index d7c74f095805a..ef4be14af3bb9 100644 --- a/drivers/infiniband/core/ucma.c +++ b/drivers/infiniband/core/ucma.c @@ -1473,7 +1473,9 @@ 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);