CVE-2022-49702

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

btrfs: fix hang during unmount when block group reclaim task is running

When we start an unmount, at close_ctree(), if we have the reclaim task

running and in the middle of a data block group relocation, we can trigger

a deadlock when stopping an async reclaim task, producing a trace like the

following:

[629724.498185] task:kworker/u16:7 state:D stack: 0 pid:681170 ppid: 2 flags:0x00004000

[629724.499760] Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs]

[629724.501267] Call Trace:

[629724.501759] <TASK>

[629724.502174] __schedule+0x3cb/0xed0

[629724.502842] schedule+0x4e/0xb0

[629724.503447] btrfs_wait_on_delayed_iputs+0x7c/0xc0 [btrfs]

[629724.504534] ? prepare_to_wait_exclusive+0xc0/0xc0

[629724.505442] flush_space+0x423/0x630 [btrfs]

[629724.506296] ? rcu_read_unlock_trace_special+0x20/0x50

[629724.507259] ? lock_release+0x220/0x4a0

[629724.507932] ? btrfs_get_alloc_profile+0

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References