From: Thadeu Lima de Souza Cascardo Date: Mon, 10 Feb 2025 19:16:22 +0000 (-0600) Subject: dlm: prevent NPD when writing a positive value to event_done X-Git-Tag: v6.15-rc1~150^2~3 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8e2bad543eca5c25cd02cbc63d72557934d45f13;p=thirdparty%2Fkernel%2Flinux.git dlm: prevent NPD when writing a positive value to event_done do_uevent returns the value written to event_done. In case it is a positive value, new_lockspace would undo all the work, and lockspace would not be set. __dlm_new_lockspace, however, would treat that positive value as a success due to commit 8511a2728ab8 ("dlm: fix use count with multiple joins"). Down the line, device_create_lockspace would pass that NULL lockspace to dlm_find_lockspace_local, leading to a NULL pointer dereference. Treating such positive values as successes prevents the problem. Given this has been broken for so long, this is unlikely to break userspace expectations. Fixes: 8511a2728ab8 ("dlm: fix use count with multiple joins") Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: David Teigland --- diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c index 8afac6e2dff00..1929327ffbe1c 100644 --- a/fs/dlm/lockspace.c +++ b/fs/dlm/lockspace.c @@ -576,7 +576,7 @@ static int new_lockspace(const char *name, const char *cluster, lockspace to start running (via sysfs) in dlm_ls_start(). */ error = do_uevent(ls, 1); - if (error) + if (error < 0) goto out_recoverd; /* wait until recovery is successful or failed */