Описание
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:
- Task A calls ioctl to disable quota. It starts a transaction and waits for qgroup rescan worker completes.
- 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.
- 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]
[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]
[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]
[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---
A vulnerability was found in the Linux kernel's btrfs file system. The quota disable process leads to a deadlock situation when the quota disable ioctl is initiated. This issue starts a transaction and waits indefinitely for the qgroup rescan worker to complete, creating a circular dependency with other tasks.
Отчет
Red Hat Enterprise Linux is not vulnerable to this CVE, as it does not affect the versions or configurations of the Linux kernel used in its distributions.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Out of support scope | ||
| Red Hat Enterprise Linux 8 | kernel | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Not affected |
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Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
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 tas...
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
In the Linux kernel, the following vulnerability has been resolved: b ...
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 tas...
EPSS
5.5 Medium
CVSS3