# CVE-2022-48734: linux: In the Linux kernel, the following vulnerability has been resolved:  btrfs: fix deadlock between quota disable and qg...

CVE-2022-48734 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-48734, released June 20, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2022-48734
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0018
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 20, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  btrfs: fix deadlock between quota disable and qgroup rescan worker  Quota disable ioctl starts a transaction before waiting for the qgroup rescan worker completes. However, this wait can be infinite and results in deadlock because of circular dependency among the quota disable ioctl, the qgroup rescan worker and the other task with transaction such as block group relocation task.  The deadlock happens with the steps following:  1) Task A calls ioctl to disable quota. It starts a transaction and    waits for qgroup rescan worker completes. 2) Task B such as block group relocation task starts a transaction and    joins to the transaction that task A started. Then task B commits to    the transaction. In this commit, task B waits for a commit by task A. 3) Task C as the qgroup rescan worker starts its job and starts a    transaction. In this transaction start, task C waits for completion    of the transaction that task A started and task B committed.  This deadlock was found with fstests test case btrfs/115 and a zoned null_blk device. The test case enables and disables quota, and the block group reclaim was triggered during the quota disable by chance. The deadlock was also observed by running quota enable and disable in parallel with 'btrfs balance' command on regular null_blk devices.  An example report of the deadlock:    [372.469894] INFO: task kworker/u16:6:103 blocked for more than 122 seconds.   [372.479944]       Not tainted 5.16.0-rc8 #7   [372.485067] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.   [372.493898] task:kworker/u16:6   state:D stack:    0 pid:  103 ppid:     2 flags:0x00004000   [372.503285] Workqueue: btrfs-qgroup-rescan btrfs_work_helper [btrfs]   [372.510782] Call Trace:   [372.514092]  <TASK>   [372.521684]  __schedule+0xb56/0x4850   [372.530104]  ? io_schedule_timeout+0x190/0x190   [372.538842]  ? lockdep_hardirqs_on+0x7e/0x100   [372.547092]  ? _raw_spin_unlock_irqrestore+0x3e/0x60   [372.555591]  schedule+0xe0/0x270   [372.561894]  btrfs_commit_transaction+0x18bb/0x2610 [btrfs]   [372.570506]  ? btrfs_apply_pending_changes+0x50/0x50 [btrfs]   [372.578875]  ? free_unref_page+0x3f2/0x650   [372.585484]  ? finish_wait+0x270/0x270   [372.591594]  ? release_extent_buffer+0x224/0x420 [btrfs]   [372.599264]  btrfs_qgroup_rescan_worker+0xc13/0x10c0 [btrfs]   [372.607157]  ? lock_release+0x3a9/0x6d0   [372.613054]  ? btrfs_qgroup_account_extent+0xda0/0xda0 [btrfs]   [372.620960]  ? do_raw_spin_lock+0x11e/0x250   [372.627137]  ? rwlock_bug.part.0+0x90/0x90   [372.633215]  ? lock_is_held_type+0xe4/0x140   [372.639404]  btrfs_work_helper+0x1ae/0xa90 [btrfs]   [372.646268]  process_one_work+0x7e9/0x1320   [372.652321]  ? lock_release+0x6d0/0x6d0   [372.658081]  ? pwq_dec_nr_in_flight+0x230/0x230   [372.664513]  ? rwlock_bug.part.0+0x90/0x90   [372.670529]  worker_thread+0x59e/0xf90   [372.676172]  ? process_one_work+0x1320/0x1320   [372.682440]  kthread+0x3b9/0x490   [372.687550]  ? _raw_spin_unlock_irq+0x24/0x50   [372.693811]  ? set_kthread_struct+0x100/0x100   [372.700052]  ret_from_fork+0x22/0x30   [372.705517]  </TASK>   [372.709747] INFO: task btrfs-transacti:2347 blocked for more than 123 seconds.   [372.729827]       Not tainted 5.16.0-rc8 #7   [372.745907] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.   [372.767106] task:btrfs-transacti state:D stack:    0 pid: 2347 ppid:     2 flags:0x00004000   [372.787776] Call Trace:   [372.801652]  <TASK>   [372.812961]  __schedule+0xb56/0x4850   [372.830011]  ? io_schedule_timeout+0x190/0x190   [372.852547]  ? lockdep_hardirqs_on+0x7e/0x100   [372.871761]  ? _raw_spin_unlock_irqrestore+0x3e/0x60   [372.886792]  schedule+0xe0/0x270   [372.901685]  wait_current_trans+0x22c/0x310 [btrfs]   [372.919743]  ? btrfs_put_transaction+0x3d0/0x3d0 [btrfs]   [372.938923]  ? finish_wait+0x270/0x270   [372.959085]  ? join_transaction+0xc7 ---truncated---

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.16.10-1 | [DEBIAN-CVE-2022-48734](https://patchblox.com/security/data/fix/linux/debian-cve-2022-48734.md) | Jun 20, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.16.10-1 | [DEBIAN-CVE-2022-48734](https://patchblox.com/security/data/fix/linux/debian-cve-2022-48734.md) | Jun 20, 2024 |
| Linux | linux Debian 14 | 5.16.10-1 | [DEBIAN-CVE-2022-48734](https://patchblox.com/security/data/fix/linux/debian-cve-2022-48734.md) | Jun 20, 2024 |

---

Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.