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authorYu Kuai <yukuai3@huawei.com>2023-03-10 15:38:51 +0800
committerSong Liu <song@kernel.org>2023-04-13 22:20:24 -0700
commit6efddf1e32e2a264694766ca485a4f5e04ee82a7 (patch)
treeb8968b451ff3df4ba17a17eceb6453f0f04e0961 /drivers/md
parentc31fea2f8e2a72c817f318016bbc327095175a9f (diff)
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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.c18
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) {