If dm_hold_control_open() isn't set, when dm_lib_release() is called, it will close the control fd. The control fd will get re-opened on the next dm_task_run() call, but if there is a dm_task_run() call already in progress in another thread, it can fail. Since many of the device-mapper callouts happen with the vecs lock held, this wasn't too noticeable, but there is code that calls dm_task_run() without the vecs lock held, notably the dmevent waiter code. Signed-off-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx> --- libmultipath/devmapper.c | 1 + 1 file changed, 1 insertion(+) diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c index bed8ddc6..d96472fe 100644 --- a/libmultipath/devmapper.c +++ b/libmultipath/devmapper.c @@ -254,6 +254,7 @@ void libmp_dm_init(void) memcpy(conf->version, version, sizeof(version)); put_multipath_config(conf); dm_init(verbosity); + dm_hold_control_dev(1); dm_udev_set_sync_support(libmp_dm_udev_sync); } -- 2.17.2 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
