CVE-2022-49702— btrfs: fix hang during unmount when block group reclaim task is running
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I. Basic Information for CVE-2022-49702
Vulnerability Information
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Vulnerability Title
btrfs: fix hang during unmount when block group reclaim task is running
Source: NVD (National Vulnerability Database)
Vulnerability 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+0xb3/0x290 [btrfs] [629724.508940] ? do_raw_spin_unlock+0x4b/0xa0 [629724.509688] btrfs_async_reclaim_metadata_space+0x139/0x320 [btrfs] [629724.510922] process_one_work+0x252/0x5a0 [629724.511694] ? process_one_work+0x5a0/0x5a0 [629724.512508] worker_thread+0x52/0x3b0 [629724.513220] ? process_one_work+0x5a0/0x5a0 [629724.514021] kthread+0xf2/0x120 [629724.514627] ? kthread_complete_and_exit+0x20/0x20 [629724.515526] ret_from_fork+0x22/0x30 [629724.516236] </TASK> [629724.516694] task:umount state:D stack: 0 pid:719055 ppid:695412 flags:0x00004000 [629724.518269] Call Trace: [629724.518746] <TASK> [629724.519160] __schedule+0x3cb/0xed0 [629724.519835] schedule+0x4e/0xb0 [629724.520467] schedule_timeout+0xed/0x130 [629724.521221] ? lock_release+0x220/0x4a0 [629724.521946] ? lock_acquired+0x19c/0x420 [629724.522662] ? trace_hardirqs_on+0x1b/0xe0 [629724.523411] __wait_for_common+0xaf/0x1f0 [629724.524189] ? usleep_range_state+0xb0/0xb0 [629724.524997] __flush_work+0x26d/0x530 [629724.525698] ? flush_workqueue_prep_pwqs+0x140/0x140 [629724.526580] ? lock_acquire+0x1a0/0x310 [629724.527324] __cancel_work_timer+0x137/0x1c0 [629724.528190] close_ctree+0xfd/0x531 [btrfs] [629724.529000] ? evict_inodes+0x166/0x1c0 [629724.529510] generic_shutdown_super+0x74/0x120 [629724.530103] kill_anon_super+0x14/0x30 [629724.530611] btrfs_kill_super+0x12/0x20 [btrfs] [629724.531246] deactivate_locked_super+0x31/0xa0 [629724.531817] cleanup_mnt+0x147/0x1c0 [629724.532319] task_work_run+0x5c/0xa0 [629724.532984] exit_to_user_mode_prepare+0x1a6/0x1b0 [629724.533598] syscall_exit_to_user_mode+0x16/0x40 [629724.534200] do_syscall_64+0x48/0x90 [629724.534667] entry_SYSCALL_64_after_hwframe+0x44/0xae [629724.535318] RIP: 0033:0x7fa2b90437a7 [629724.535804] RSP: 002b:00007ffe0b7e4458 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [629724.536912] RAX: 0000000000000000 RBX: 00007fa2b9182264 RCX: 00007fa2b90437a7 [629724.538156] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000555d6cf20dd0 [629724.539053] RBP: 0000555d6cf20ba0 R08: 0000000000000000 R09: 00007ffe0b7e3200 [629724.539956] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [629724.540883] R13: 0000555d6cf20dd0 R14: 0000555d6cf20cb0 R15: 0000000000000000 [629724.541796] </TASK> This happens because: 1) Before entering close_ctree() we have the async block group reclaim task running and relocating a data block group; 2) There's an async metadata (or data) space reclaim task running; 3) We enter close_ctree() and park the cleaner kthread; 4) The async space reclaim task is at flush_space() and runs all the existing delayed iputs; 5) Before the async space reclaim task calls btrfs_wait_on_delayed_iputs(), the block group reclaim task which is doing the data block group relocation, creates a delayed iput at replace_file_extents() (called when COWing leaves that have file extent items pointing to relocated data exten ---truncated---
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于btrfs在卸载时与块组回收任务发生死锁。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2022-49702
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Same Patch Batch · Linux · 2025-02-26 · 706 CVEs total
| CVE-2022-49496 | media: mediatek: vcodec: prevent kernel crash when rmmod mtk-vcodec-dec.ko | |
| CVE-2022-49487 | mtd: rawnand: intel: fix possible null-ptr-deref in ebu_nand_probe() | |
| CVE-2022-49486 | ASoC: fsl: Fix refcount leak in imx_sgtl5000_probe | |
| CVE-2022-49488 | drm/msm/mdp5: Return error code in mdp5_mixer_release when deadlock is detected | |
| CVE-2022-49489 | drm/msm/disp/dpu1: set vbif hw config to NULL to avoid use after memory free during pm run | |
| CVE-2022-49490 | drm/msm/mdp5: Return error code in mdp5_pipe_release when deadlock is detected | |
| CVE-2022-49491 | drm/rockchip: vop: fix possible null-ptr-deref in vop_bind() | |
| CVE-2022-49492 | nvme-pci: fix a NULL pointer dereference in nvme_alloc_admin_tags | |
| CVE-2022-49493 | ASoC: rt5645: Fix errorenous cleanup order | |
| CVE-2022-49494 | mtd: rawnand: cadence: fix possible null-ptr-deref in cadence_nand_dt_probe() | |
| CVE-2022-49495 | drm/msm/hdmi: check return value after calling platform_get_resource_byname() | |
| CVE-2022-49497 | net: remove two BUG() from skb_checksum_help() | |
| CVE-2022-49503 | ath9k_htc: fix potential out of bounds access with invalid rxstatus->rs_keyix | |
| CVE-2022-49508 | HID: elan: Fix potential double free in elan_input_configured | |
| CVE-2022-49506 | drm/mediatek: Add vblank register/unregister callback functions | |
| CVE-2022-49504 | scsi: lpfc: Inhibit aborts if external loopback plug is inserted | |
| CVE-2022-49505 | NFC: NULL out the dev->rfkill to prevent UAF | |
| CVE-2022-49502 | media: rga: fix possible memory leak in rga_probe | |
| CVE-2022-49499 | drm/msm: Fix null pointer dereferences without iommu | |
| CVE-2022-49498 | ALSA: pcm: Check for null pointer of pointer substream before dereferencing it |
Showing top 20 of 706 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
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Same vendor: Linux
- CVE-2026-43490
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ata: libata-core: Disable LPM on ST1000DM010-2EP102 - CVE-2026-43488
usb: xhci: Prevent interrupt storm on host controller error - CVE-2026-43485
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