CVE-2023-52668 Information

Description

In the Linux kernel the following vulnerability has been resolved:

btrfs: zoned: fix lock ordering in btrfs_zone_activate()

The btrfs CI reported a lockdep warning as follows by running generic generic/129.

WARNING: possible circular locking dependency detected 6.7.0-rc5+ 1 Not tainted

kworker/u5:5/793427 is trying to acquire lock: ffff88813256d028 (&cache->lock)+.+.-2:2 at: btrfs_zone_finish_one_bg+0x5e/0x130 but task is already holding lock: ffff88810a23a318 (&fs_info->zone_active_bgs_lock)+.+.-2:2 at: btrfs_zone_finish_one_bg+0x34/0x130 which lock already depends on the new lock.

the existing dependency chain (in reverse order) is: -> 1 (&fs_info->zone_active_bgs_lock)+.+.-2:2: … -> 0 (&cache->lock)+.+.-2:2: …

This is because we take fs_info->zone_active_bgs_lock after a block_group’s lock in btrfs_zone_activate() while doing the opposite in other places.

Fix the issue by expanding the fs_info->zone_active_bgs_lock’s critical section and taking it before a block_group’s lock.

Reference

https://git.kernel.org/stable/c/6f74989f5909cdec9b1274641f0fa306b15bb476 https://git.kernel.org/stable/c/1908e9d01e5395adff68d9d308a0fb15337e6272 https://git.kernel.org/stable/c/b18f3b60b35a8c01c9a2a0f0d6424c6d73971dc3