The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From ae4d37b5df749926891583d42a6801b5da11e3c1 Mon Sep 17 00:00:00 2001 From: Xiaomeng Tong xiam0nd.tong@gmail.com Date: Wed, 6 Apr 2022 21:04:44 +0200 Subject: [PATCH] drbd: fix an invalid memory access caused by incorrect use of list iterator MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
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@vger.kernel.org Fixes: c06ece6ba6f1b ("drbd: Turn connection->volumes into connection->peer_devices") Signed-off-by: Xiaomeng Tong xiam0nd.tong@gmail.com Reviewed-by: Christoph Böhmwalder christoph.boehmwalder@linbit.com Reviewed-by: Lars Ellenberg lars.ellenberg@linbit.com Signed-off-by: Jens Axboe axboe@kernel.dk
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 9676a1d214bc..d6dfa286ddb3 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -2773,12 +2773,12 @@ 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; @@ -2792,8 +2792,6 @@ 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);