6.7-stable review patch. If anyone has any objections, please let me know.
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From: Yu Kuai yukuai3@huawei.com
commit ad39c08186f8a0f221337985036ba86731d6aafe upstream.
Currently, if reshape is interrupted, then reassemble the array will register sync_thread directly from pers->run(), in this case 'MD_RECOVERY_RUNNING' is set directly, however, there is no guarantee that md_do_sync() will be executed, hence stop_sync_thread() will hang because 'MD_RECOVERY_RUNNING' can't be cleared.
Last patch make sure that md_do_sync() will set MD_RECOVERY_DONE, however, following hang can still be triggered by dm-raid test shell/lvconvert-raid-reshape.sh occasionally:
[root@fedora ~]# cat /proc/1982/stack [<0>] stop_sync_thread+0x1ab/0x270 [md_mod] [<0>] md_frozen_sync_thread+0x5c/0xa0 [md_mod] [<0>] raid_presuspend+0x1e/0x70 [dm_raid] [<0>] dm_table_presuspend_targets+0x40/0xb0 [dm_mod] [<0>] __dm_destroy+0x2a5/0x310 [dm_mod] [<0>] dm_destroy+0x16/0x30 [dm_mod] [<0>] dev_remove+0x165/0x290 [dm_mod] [<0>] ctl_ioctl+0x4bb/0x7b0 [dm_mod] [<0>] dm_ctl_ioctl+0x11/0x20 [dm_mod] [<0>] vfs_ioctl+0x21/0x60 [<0>] __x64_sys_ioctl+0xb9/0xe0 [<0>] do_syscall_64+0xc6/0x230 [<0>] entry_SYSCALL_64_after_hwframe+0x6c/0x74
Meanwhile mddev->recovery is: MD_RECOVERY_RUNNING | MD_RECOVERY_INTR | MD_RECOVERY_RESHAPE | MD_RECOVERY_FROZEN
Fix this problem by remove the code to register sync_thread directly from raid10 and raid5. And let md_check_recovery() to register sync_thread.
Fixes: f67055780caa ("[PATCH] md: Checkpoint and allow restart of raid5 reshape") Fixes: f52f5c71f3d4 ("md: fix stopping sync thread") Cc: stable@vger.kernel.org # v6.7+ Signed-off-by: Yu Kuai yukuai3@huawei.com Signed-off-by: Song Liu song@kernel.org Link: https://lore.kernel.org/r/20240201092559.910982-5-yukuai1@huaweicloud.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/md.c | 5 ++++- drivers/md/raid10.c | 16 ++-------------- drivers/md/raid5.c | 29 ++--------------------------- 3 files changed, 8 insertions(+), 42 deletions(-)
--- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -9422,6 +9422,7 @@ static void md_start_sync(struct work_st struct mddev *mddev = container_of(ws, struct mddev, sync_work); int spares = 0; bool suspend = false; + char *name;
if (md_spares_need_change(mddev)) suspend = true; @@ -9454,8 +9455,10 @@ static void md_start_sync(struct work_st if (spares) md_bitmap_write_all(mddev->bitmap);
+ name = test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) ? + "reshape" : "resync"; rcu_assign_pointer(mddev->sync_thread, - md_register_thread(md_do_sync, mddev, "resync")); + md_register_thread(md_do_sync, mddev, name)); if (!mddev->sync_thread) { pr_warn("%s: could not start resync thread...\n", mdname(mddev)); --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -4307,11 +4307,7 @@ static int raid10_run(struct mddev *mdde clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); - set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); - rcu_assign_pointer(mddev->sync_thread, - md_register_thread(md_do_sync, mddev, "reshape")); - if (!mddev->sync_thread) - goto out_free_conf; + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); }
return 0; @@ -4707,16 +4703,8 @@ out: clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); clear_bit(MD_RECOVERY_DONE, &mddev->recovery); set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); - set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); - - rcu_assign_pointer(mddev->sync_thread, - md_register_thread(md_do_sync, mddev, "reshape")); - if (!mddev->sync_thread) { - ret = -EAGAIN; - goto abort; - } + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); conf->reshape_checkpoint = jiffies; - md_wakeup_thread(mddev->sync_thread); md_new_event(); return 0;
--- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -8002,11 +8002,7 @@ static int raid5_run(struct mddev *mddev clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); - set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); - rcu_assign_pointer(mddev->sync_thread, - md_register_thread(md_do_sync, mddev, "reshape")); - if (!mddev->sync_thread) - goto abort; + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); }
/* Ok, everything is just fine now */ @@ -8585,29 +8581,8 @@ static int raid5_start_reshape(struct md clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); clear_bit(MD_RECOVERY_DONE, &mddev->recovery); set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); - set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); - rcu_assign_pointer(mddev->sync_thread, - md_register_thread(md_do_sync, mddev, "reshape")); - if (!mddev->sync_thread) { - mddev->recovery = 0; - spin_lock_irq(&conf->device_lock); - write_seqcount_begin(&conf->gen_lock); - mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks; - mddev->new_chunk_sectors = - conf->chunk_sectors = conf->prev_chunk_sectors; - mddev->new_layout = conf->algorithm = conf->prev_algo; - rdev_for_each(rdev, mddev) - rdev->new_data_offset = rdev->data_offset; - smp_wmb(); - conf->generation --; - conf->reshape_progress = MaxSector; - mddev->reshape_position = MaxSector; - write_seqcount_end(&conf->gen_lock); - spin_unlock_irq(&conf->device_lock); - return -EAGAIN; - } + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); conf->reshape_checkpoint = jiffies; - md_wakeup_thread(mddev->sync_thread); md_new_event(); return 0; }