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| author | Yu Kuai <yukuai3@huawei.com> | 2023-03-10 15:38:51 +0800 |
|---|---|---|
| committer | Song Liu <song@kernel.org> | 2023-04-13 22:20:24 -0700 |
| commit | 6efddf1e32e2a264694766ca485a4f5e04ee82a7 (patch) | |
| tree | b8968b451ff3df4ba17a17eceb6453f0f04e0961 /drivers/md | |
| parent | c31fea2f8e2a72c817f318016bbc327095175a9f (diff) | |
| download | lwn-6efddf1e32e2a264694766ca485a4f5e04ee82a7.tar.gz lwn-6efddf1e32e2a264694766ca485a4f5e04ee82a7.zip | |
md: fix soft lockup in status_resync
status_resync() will calculate 'curr_resync - recovery_active' to show
user a progress bar like following:
[============>........] resync = 61.4%
'curr_resync' and 'recovery_active' is updated in md_do_sync(), and
status_resync() can read them concurrently, hence it's possible that
'curr_resync - recovery_active' can overflow to a huge number. In this
case status_resync() will be stuck in the loop to print a large amount
of '=', which will end up soft lockup.
Fix the problem by setting 'resync' to MD_RESYNC_ACTIVE in this case,
this way resync in progress will be reported to user.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230310073855.1337560-3-yukuai1@huaweicloud.com
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/md.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 63722035983d..122ae28e785c 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8032,16 +8032,16 @@ static int status_resync(struct seq_file *seq, struct mddev *mddev) } else if (resync > max_sectors) { resync = max_sectors; } else { - resync -= atomic_read(&mddev->recovery_active); - if (resync < MD_RESYNC_ACTIVE) { - /* - * Resync has started, but the subtraction has - * yielded one of the special values. Force it - * to active to ensure the status reports an - * active resync. - */ + res = atomic_read(&mddev->recovery_active); + /* + * Resync has started, but the subtraction has overflowed or + * yielded one of the special values. Force it to active to + * ensure the status reports an active resync. + */ + if (resync < res || resync - res < MD_RESYNC_ACTIVE) resync = MD_RESYNC_ACTIVE; - } + else + resync -= res; } if (resync == MD_RESYNC_NONE) { |