5.5

CVE-2022-48664: btrfs: fix hang during unmount when stopping a space reclaim worker

Analyzed
AliasesUBUNTU-CVE-2022-48664DEBIAN-CVE-2022-48664
Published 28-04-2024Last modified 23-05-2026

Vulnerability summary

CVE-2022-48664 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 14.6% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.24%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 9 · Related 9
SUSE-SU-2024:3983-1SUSE-SU-2024:3985-1SUSE-SU-2024:4081-1SUSE-SU-2024:4082-1SUSE-SU-2024:4103-1SUSE-SU-2024:4131-1

Timeline

  1. 28-04-2024
    PublishedVulnerability first disclosed.
  2. 23-05-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix hang during unmount when stopping a space reclaim worker Often when running generic/562 from fstests we can hang during unmount, resulting in a trace like this: Sep 07 11:52:00 debian9 unknown: run fstests generic/562 at 2022-09-07 11:52:00 Sep 07 11:55:32 debian9 kernel: INFO: task umount:49438 blocked for more than 120 seconds. Sep 07 11:55:32 debian9 kernel: Not tainted 6.0.0-rc2-btrfs-next-122 #1 Sep 07 11:55:32 debian9 kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Sep 07 11:55:32 debian9 kernel: task:umount state:D stack: 0 pid:49438 ppid: 25683 flags:0x00004000 Sep 07 11:55:32 debian9 kernel: Call Trace: Sep 07 11:55:32 debian9 kernel: <TASK> Sep 07 11:55:32 debian9 kernel: __schedule+0x3c8/0xec0 Sep 07 11:55:32 debian9 kernel: ? rcu_read_lock_sched_held+0x12/0x70 Sep 07 11:55:32 debian9 kernel: schedule+0x5d/0xf0 Sep 07 11:55:32 debian9 kernel: schedule_timeout+0xf1/0x130 Sep 07 11:55:32 debian9 kernel: ? lock_release+0x224/0x4a0 Sep 07 11:55:32 debian9 kernel: ? lock_acquired+0x1a0/0x420 Sep 07 11:55:32 debian9 kernel: ? trace_hardirqs_on+0x2c/0xd0 Sep 07 11:55:32 debian9 kernel: __wait_for_common+0xac/0x200 Sep 07 11:55:32 debian9 kernel: ? usleep_range_state+0xb0/0xb0 Sep 07 11:55:32 debian9 kernel: __flush_work+0x26d/0x530 Sep 07 11:55:32 debian9 kernel: ? flush_workqueue_prep_pwqs+0x140/0x140 Sep 07 11:55:32 debian9 kernel: ? trace_clock_local+0xc/0x30 Sep 07 11:55:32 debian9 kernel: __cancel_work_timer+0x11f/0x1b0 Sep 07 11:55:32 debian9 kernel: ? close_ctree+0x12b/0x5b3 [btrfs] Sep 07 11:55:32 debian9 kernel: ? __trace_bputs+0x10b/0x170 Sep 07 11:55:32 debian9 kernel: close_ctree+0x152/0x5b3 [btrfs] Sep 07 11:55:32 debian9 kernel: ? evict_inodes+0x166/0x1c0 Sep 07 11:55:32 debian9 kernel: generic_shutdown_super+0x71/0x120 Sep 07 11:55:32 debian9 kernel: kill_anon_super+0x14/0x30 Sep 07 11:55:32 debian9 kernel: btrfs_kill_super+0x12/0x20 [btrfs] Sep 07 11:55:32 debian9 kernel: deactivate_locked_super+0x2e/0xa0 Sep 07 11:55:32 debian9 kernel: cleanup_mnt+0x100/0x160 Sep 07 11:55:32 debian9 kernel: task_work_run+0x59/0xa0 Sep 07 11:55:32 debian9 kernel: exit_to_user_mode_prepare+0x1a6/0x1b0 Sep 07 11:55:32 debian9 kernel: syscall_exit_to_user_mode+0x16/0x40 Sep 07 11:55:32 debian9 kernel: do_syscall_64+0x48/0x90 Sep 07 11:55:32 debian9 kernel: entry_SYSCALL_64_after_hwframe+0x63/0xcd Sep 07 11:55:32 debian9 kernel: RIP: 0033:0x7fcde59a57a7 Sep 07 11:55:32 debian9 kernel: RSP: 002b:00007ffe914217c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 Sep 07 11:55:32 debian9 kernel: RAX: 0000000000000000 RBX: 00007fcde5ae8264 RCX: 00007fcde59a57a7 Sep 07 11:55:32 debian9 kernel: RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000055b57556cdd0 Sep 07 11:55:32 debian9 kernel: RBP: 000055b57556cba0 R08: 0000000000000000 R09: 00007ffe91420570 Sep 07 11:55:32 debian9 kernel: R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 Sep 07 11:55:32 debian9 kernel: R13: 000055b57556cdd0 R14: 000055b57556ccb8 R15: 0000000000000000 Sep 07 11:55:32 debian9 kernel: </TASK> What happens is the following: 1) The cleaner kthread tries to start a transaction to delete an unused block group, but the metadata reservation can not be satisfied right away, so a reservation ticket is created and it starts the async metadata reclaim task (fs_info->async_reclaim_work); 2) Writeback for all the filler inodes with an i_size of 2K starts (generic/562 creates a lot of 2K files with the goal of filling metadata space). We try to create an inline extent for them, but we fail when trying to insert the inline extent with -ENOSPC (at cow_file_range_inline()) - since this is not critical, we fallback to non-inline mode (back to cow_file_range()), reserve extents ---truncated---

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.24%

Chance of exploitation in the next 30 days

Percentile

15%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.24% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu101 products
  • linuxAll versions (No fix recorded) | < 5.15.0-57.63
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1027.31
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ d6fd0ae25c6495674dc5a41a8d16bc8e0073276d, < 6ac5b52e3f352f9cb270c89e6e1d4dadb564ddb8 | ≥ d6fd0ae25c6495674dc5a41a8d16bc8e0073276d, < d8a76a2e514fbbb315a6dfff2d342de2de833994 | ≥ d6fd0ae25c6495674dc5a41a8d16bc8e0073276d, < c338bea1fec5504290dc0acf026c9e7dba25004b | ≥ d6fd0ae25c6495674dc5a41a8d16bc8e0073276d, < a362bb864b8db4861977d00bd2c3222503ccc34b | 1ec2bf44c3770b9c3d510b1e78d50cd7fd19e8c5 | b4c7c826709b7d882ec9b264d5032e887e6bd720 | ≥ 4.14.120, < 4.15 | ≥ 4.19.12, < 4.20 | 4.20
  • linux_kernel≥ 4.14.120, < 4.15 | ≥ 4.19.12, < 4.20 | ≥ 4.20.1, < 5.10.147 | ≥ 5.11, < 5.15.71 | ≥ 5.16, < 5.19.12 | 4.20 | 4.20:rc2 | 4.20:rc3 | 4.20:rc4 | 4.20:rc5 | 4.20:rc6 | 4.20:rc7 | 6.0:rc1 | 6.0:rc2 | 6.0:rc3 | 6.0:rc4 | 6.0:rc5 | 6.0:rc6
Debian1 product
  • linux< 6.0.2-1

3 vendors · 104 products

References

8 links