Skip to contentSkip to conversation

FAILED: Patch "md/dm-raid: don't call md_reap_sync_thread() directly" failed to apply to 6.1-stable tree

PATCH Sasha Levin 1 participant 1 message Mar 27, 2024

Subsystems (2)
Stable branch Device mapper
lore
Share & tools
lore

Sasha Levin

author maintainer
#0 lore raw

The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From cd32b27a66db8776d8b8e82ec7d7dde97a8693b0 Mon Sep 17 00:00:00 2001
From: Yu Kuai <[email protected]>
Date: Tue, 5 Mar 2024 15:23:03 +0800
Subject: [PATCH] md/dm-raid: don't call md_reap_sync_thread() directly

Currently md_reap_sync_thread() is called from raid_message() directly without holding 'reconfig_mutex', this is definitely unsafe because md_reap_sync_thread() can change many fields that is protected by 'reconfig_mutex'.

However, hold 'reconfig_mutex' here is still problematic because this will cause deadlock, for example, commit 130443d60b1b ("md: refactor idle/frozen_sync_thread() to fix deadlock").

Fix this problem by using stop_sync_thread() to unregister sync_thread, like md/raid did.

Fixes be83651f0050 ("DM RAID: Add message/status support for changing sync action")
Cc [email protected] # v6.7+
Signed-off-by Yu Kuai <[email protected]>
Signed-off-by Xiao Ni <[email protected]>
Acked-by Mike Snitzer <[email protected]>
Signed-off-by Song Liu <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
---
 drivers/md/dm-raid.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)
drivers/md/dm-raid.c +18 -10
index e2d7a73c0f874..47c4b1b6e532a 100644
@@ -3719,6 +3719,7 @@ static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
 {
 	struct raid_set *rs = ti->private;
 	struct mddev *mddev = &rs->md;
+	int ret = 0;
 
 	if (!mddev->pers || !mddev->pers->sync_request)
 		return -EINVAL;

@@ -3726,17 +3727,24 @@ static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
 	if (test_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags))
 		return -EBUSY;
 
-	if (!strcasecmp(argv[0], "frozen"))
-		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
-	else
-		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+	if (!strcasecmp(argv[0], "frozen")) {
+		ret = mddev_lock(mddev);
+		if (ret)
+			return ret;
 
-	if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
-		if (mddev->sync_thread) {
-			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
-			md_reap_sync_thread(mddev);
-		}
-	} else if (decipher_sync_action(mddev, mddev->recovery) != st_idle)
+		md_frozen_sync_thread(mddev);
+		mddev_unlock(mddev);
+	} else if (!strcasecmp(argv[0], "idle")) {
+		ret = mddev_lock(mddev);
+		if (ret)
+			return ret;
+
+		md_idle_sync_thread(mddev);
+		mddev_unlock(mddev);
+	}
+
+	clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+	if (decipher_sync_action(mddev, mddev->recovery) != st_idle)
 		return -EBUSY;
 	else if (!strcasecmp(argv[0], "resync"))
 		; /* MD_RECOVERY_NEEDED set below */
Signature · 1 line
2.43.0