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| author | Yu Kuai <yukuai@fnnas.com> | 2026-03-27 17:07:29 +0300 |
|---|---|---|
| committer | Yu Kuai <yukuai@fnnas.com> | 2026-04-07 08:09:22 +0300 |
| commit | cf86bb53b9c92354904a328e947a05ffbfdd1840 (patch) | |
| tree | 542c9f03c0db0d848eef3481d52232e95ecdc313 | |
| parent | 808cec74601cfddea87b6970134febfdc7f574b9 (diff) | |
| download | linux-cf86bb53b9c92354904a328e947a05ffbfdd1840.tar.xz | |
md: wake raid456 reshape waiters before suspend
During raid456 reshape, direct IO across the reshape position can sleep
in raid5_make_request() waiting for reshape progress while still
holding an active_io reference. If userspace then freezes reshape and
writes md/suspend_lo or md/suspend_hi, mddev_suspend() kills active_io
and waits for all in-flight IO to drain.
This can deadlock: the IO needs reshape progress to continue, but the
reshape thread is already frozen, so the active_io reference is never
dropped and suspend never completes.
raid5_prepare_suspend() already wakes wait_for_reshape for dm-raid. Do
the same for normal md suspend when reshape is already interrupted, so
waiting raid456 IO can abort, drop its reference, and let suspend
finish.
The mdadm test tests/25raid456-reshape-deadlock reproduces the hang.
Fixes: 714d20150ed8 ("md: add new helpers to suspend/resume array")
Link: https://lore.kernel.org/linux-raid/20260327140729.2030564-1-yukuai@fnnas.com/
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
| -rw-r--r-- | drivers/md/md.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 67e2b501d94f..5fb5ae8368ba 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -487,6 +487,17 @@ int mddev_suspend(struct mddev *mddev, bool interruptible) } percpu_ref_kill(&mddev->active_io); + + /* + * RAID456 IO can sleep in wait_for_reshape while still holding an + * active_io reference. If reshape is already interrupted or frozen, + * wake those waiters so they can abort and drop the reference instead + * of deadlocking suspend. + */ + if (mddev->pers && mddev->pers->prepare_suspend && + reshape_interrupted(mddev)) + mddev->pers->prepare_suspend(mddev); + if (interruptible) err = wait_event_interruptible(mddev->sb_wait, percpu_ref_is_zero(&mddev->active_io)); |