[PATCH 6.5 289/739] md/md-bitmap: hold reconfig_mutex in backlog_store()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



6.5-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yu Kuai <yukuai3@xxxxxxxxxx>

[ Upstream commit 44abfa6a95df425c0660d56043020b67e6d93ab8 ]

Several reasons why 'reconfig_mutex' should be held:

1) rdev_for_each() is not safe to be called without the lock, because
   rdev can be removed concurrently.
2) mddev_destroy_serial_pool() and mddev_create_serial_pool() should not
   be called concurrently.
3) mddev_suspend() from mddev_destroy/create_serial_pool() should be
   protected by the lock.

Fixes: 10c92fca636e ("md-bitmap: create and destroy wb_info_pool with the change of backlog")
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230706083727.608914-3-yukuai1@xxxxxxxxxxxxxxx
Signed-off-by: Song Liu <song@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/md/md-bitmap.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 697ca41c186c6..a08bf6b9accb4 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -2542,6 +2542,10 @@ backlog_store(struct mddev *mddev, const char *buf, size_t len)
 	if (backlog > COUNTER_MAX)
 		return -EINVAL;
 
+	rv = mddev_lock(mddev);
+	if (rv)
+		return rv;
+
 	/*
 	 * Without write mostly device, it doesn't make sense to set
 	 * backlog for max_write_behind.
@@ -2555,6 +2559,7 @@ backlog_store(struct mddev *mddev, const char *buf, size_t len)
 	if (!has_write_mostly) {
 		pr_warn_ratelimited("%s: can't set backlog, no write mostly device available\n",
 				    mdname(mddev));
+		mddev_unlock(mddev);
 		return -EINVAL;
 	}
 
@@ -2570,6 +2575,8 @@ backlog_store(struct mddev *mddev, const char *buf, size_t len)
 	}
 	if (old_mwb != backlog)
 		md_bitmap_update_sb(mddev->bitmap);
+
+	mddev_unlock(mddev);
 	return len;
 }
 
-- 
2.40.1






[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux