6.6-stable review patch. If anyone has any objections, please let me know.
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From: Yu Kuai yukuai3@huawei.com
commit 855678ed8534518e2b428bcbcec695de9ba248e8 upstream.
submit_flushes atomic_set(&mddev->flush_pending, 1); rdev_for_each_rcu(rdev, mddev) atomic_inc(&mddev->flush_pending); bi->bi_end_io = md_end_flush submit_bio(bi); /* flush io is done first */ md_end_flush if (atomic_dec_and_test(&mddev->flush_pending)) percpu_ref_put(&mddev->active_io) -> active_io is not released
if (atomic_dec_and_test(&mddev->flush_pending)) -> missing release of active_io
For consequence, mddev_suspend() will wait for 'active_io' to be zero forever.
Fix this problem by releasing 'active_io' in submit_flushes() if 'flush_pending' is decreased to zero.
Fixes: fa2bbff7b0b4 ("md: synchronize flush io with array reconfiguration") Cc: stable@vger.kernel.org # v6.1+ Reported-by: Blazej Kucman blazej.kucman@linux.intel.com Closes: https://lore.kernel.org/lkml/20240130172524.0000417b@linux.intel.com/ Signed-off-by: Yu Kuai yukuai3@huawei.com Signed-off-by: Song Liu song@kernel.org Link: https://lore.kernel.org/r/20240201092559.910982-7-yukuai1@huaweicloud.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/md.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -530,8 +530,12 @@ static void submit_flushes(struct work_s rcu_read_lock(); } rcu_read_unlock(); - if (atomic_dec_and_test(&mddev->flush_pending)) + if (atomic_dec_and_test(&mddev->flush_pending)) { + /* The pair is percpu_ref_get() from md_flush_request() */ + percpu_ref_put(&mddev->active_io); + queue_work(md_wq, &mddev->flush_work); + } }
static void md_submit_flush_data(struct work_struct *ws)