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Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"

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[ Upstream commit bed9e27baf52a09b7ba2a3714f1e24e17ced386d ]

This reverts commit 5e2cf333b7bd5d3e62595a44d598a254c697cd74.

That commit introduced the following race and can cause system hung.

 md_write_start:             raid5d:
 // mddev->in_sync == 1
 set "MD_SB_CHANGE_PENDING"
                            // running before md_write_start wakeup it
                             waiting "MD_SB_CHANGE_PENDING" cleared
                             >>>>>>>>> hung
 wakeup mddev->thread
 ...
 waiting "MD_SB_CHANGE_PENDING" cleared
 >>>> hung, raid5d should clear this flag
 but get hung by same flag.

The issue reverted commit fixing is fixed by last patch in a new way.

Fixes: 5e2cf333b7bd ("md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d")
Cc: stable@vger.kernel.org # v5.19+
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20231108182216.73611-2-junxiao.bi@oracle.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 1e8c1c2a92692881ac7ec92dcf1c8a846584251b)
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
This commit is contained in:
Junxiao Bi 2023-11-08 10:22:16 -08:00 committed by Vegard Nossum
parent 70bd0bc34e
commit 072057390d
1 changed files with 0 additions and 12 deletions
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12
drivers/md/raid5.c
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@ -44,7 +44,6 @@
*/ */
#include <linux/blkdev.h> #include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/kthread.h> #include <linux/kthread.h>
#include <linux/raid/pq.h> #include <linux/raid/pq.h>
#include <linux/async_tx.h> #include <linux/async_tx.h>
@ -6309,18 +6308,7 @@ static void raid5d(struct md_thread *thread)
spin_unlock_irq(&conf->device_lock); spin_unlock_irq(&conf->device_lock);
md_check_recovery(mddev); md_check_recovery(mddev);
spin_lock_irq(&conf->device_lock); spin_lock_irq(&conf->device_lock);
/*
* Waiting on MD_SB_CHANGE_PENDING below may deadlock
* seeing md_check_recovery() is needed to clear
* the flag when using mdmon.
*/
continue;
} }
wait_event_lock_irq(mddev->sb_wait,
!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
conf->device_lock);
} }
pr_debug("%d stripes handled\n", handled); pr_debug("%d stripes handled\n", handled);