diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2020-07-08 19:25:20 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-07-16 09:17:27 +0300 |
| commit | 35a9af8ddb6271fb20b9f4fa07c26fec1e6c52df (patch) | |
| tree | 2eca3c6ce309d36ce870a257e5b9f5890099edf0 /drivers/md | |
| parent | 8e5d3786da3acbd91385fdc6ffabf597d90e802d (diff) | |
| download | linux-35a9af8ddb6271fb20b9f4fa07c26fec1e6c52df.tar.xz | |
dm: use noio when sending kobject event
commit 6958c1c640af8c3f40fa8a2eee3b5b905d95b677 upstream.
kobject_uevent may allocate memory and it may be called while there are dm
devices suspended. The allocation may recurse into a suspended device,
causing a deadlock. We must set the noio flag when sending a uevent.
The observed deadlock was reported here:
https://www.redhat.com/archives/dm-devel/2020-March/msg00025.html
Reported-by: Khazhismel Kumykov <khazhy@google.com>
Reported-by: Tahsin Erdogan <tahsin@google.com>
Reported-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 43643151584a..afc9f8406dce 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -12,6 +12,7 @@ #include <linux/init.h> #include <linux/module.h> #include <linux/mutex.h> +#include <linux/sched/mm.h> #include <linux/sched/signal.h> #include <linux/blkpg.h> #include <linux/bio.h> @@ -2853,17 +2854,25 @@ EXPORT_SYMBOL_GPL(dm_internal_resume_fast); int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action, unsigned cookie) { + int r; + unsigned noio_flag; char udev_cookie[DM_COOKIE_LENGTH]; char *envp[] = { udev_cookie, NULL }; + noio_flag = memalloc_noio_save(); + if (!cookie) - return kobject_uevent(&disk_to_dev(md->disk)->kobj, action); + r = kobject_uevent(&disk_to_dev(md->disk)->kobj, action); else { snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u", DM_COOKIE_ENV_VAR_NAME, cookie); - return kobject_uevent_env(&disk_to_dev(md->disk)->kobj, - action, envp); + r = kobject_uevent_env(&disk_to_dev(md->disk)->kobj, + action, envp); } + + memalloc_noio_restore(noio_flag); + + return r; } uint32_t dm_next_uevent_seq(struct mapped_device *md) |