This is a note to let you know that I've just added the patch titled drbd: fix an invalid memory access caused by incorrect use of list iterator to the 5.15-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: drbd-fix-an-invalid-memory-access-caused-by-incorrec.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit b95039363a3ed89cf8d474e1d691d9dbf5322b73 Author: Xiaomeng Tong <xiam0nd.tong@xxxxxxxxx> Date: Wed Apr 6 21:04:44 2022 +0200 drbd: fix an invalid memory access caused by incorrect use of list iterator [ Upstream commit ae4d37b5df749926891583d42a6801b5da11e3c1 ] The bug is here: idr_remove(&connection->peer_devices, vnr); If the previous for_each_connection() don't exit early (no goto hit inside the loop), the iterator 'connection' after the loop will be a bogus pointer to an invalid structure object containing the HEAD (&resource->connections). As a result, the use of 'connection' above will lead to a invalid memory access (including a possible invalid free as idr_remove could call free_layer). The original intention should have been to remove all peer_devices, but the following lines have already done the work. So just remove this line and the unneeded label, to fix this bug. Cc: stable@xxxxxxxxxxxxxxx Fixes: c06ece6ba6f1b ("drbd: Turn connection->volumes into connection->peer_devices") Signed-off-by: Xiaomeng Tong <xiam0nd.tong@xxxxxxxxx> Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@xxxxxxxxxx> Reviewed-by: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index b91d2a9dc238..d59af26d7703 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -2795,12 +2795,12 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig if (init_submitter(device)) { err = ERR_NOMEM; - goto out_idr_remove_vol; + goto out_idr_remove_from_resource; } err = add_disk(disk); if (err) - goto out_idr_remove_vol; + goto out_idr_remove_from_resource; /* inherit the connection state */ device->state.conn = first_connection(resource)->cstate; @@ -2814,8 +2814,6 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig drbd_debugfs_device_add(device); return NO_ERROR; -out_idr_remove_vol: - idr_remove(&connection->peer_devices, vnr); out_idr_remove_from_resource: for_each_connection(connection, resource) { peer_device = idr_remove(&connection->peer_devices, vnr);