CVE-2022-50089

Published Jun 18, 2025

Last updated 7 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: btrfs: ensure pages are unlocked on cow_file_range() failure There is a hung_task report on zoned btrfs like below. https://github.com/naota/linux/issues/59 [726.328648] INFO: task rocksdb:high0:11085 blocked for more than 241 seconds. [726.329839] Not tainted 5.16.0-rc1+ #1 [726.330484] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [726.331603] task:rocksdb:high0 state:D stack: 0 pid:11085 ppid: 11082 flags:0x00000000 [726.331608] Call Trace: [726.331611] <TASK> [726.331614] __schedule+0x2e5/0x9d0 [726.331622] schedule+0x58/0xd0 [726.331626] io_schedule+0x3f/0x70 [726.331629] __folio_lock+0x125/0x200 [726.331634] ? find_get_entries+0x1bc/0x240 [726.331638] ? filemap_invalidate_unlock_two+0x40/0x40 [726.331642] truncate_inode_pages_range+0x5b2/0x770 [726.331649] truncate_inode_pages_final+0x44/0x50 [726.331653] btrfs_evict_inode+0x67/0x480 [726.331658] evict+0xd0/0x180 [726.331661] iput+0x13f/0x200 [726.331664] do_unlinkat+0x1c0/0x2b0 [726.331668] __x64_sys_unlink+0x23/0x30 [726.331670] do_syscall_64+0x3b/0xc0 [726.331674] entry_SYSCALL_64_after_hwframe+0x44/0xae [726.331677] RIP: 0033:0x7fb9490a171b [726.331681] RSP: 002b:00007fb943ffac68 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 [726.331684] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb9490a171b [726.331686] RDX: 00007fb943ffb040 RSI: 000055a6bbe6ec20 RDI: 00007fb94400d300 [726.331687] RBP: 00007fb943ffad00 R08: 0000000000000000 R09: 0000000000000000 [726.331688] R10: 0000000000000031 R11: 0000000000000246 R12: 00007fb943ffb000 [726.331690] R13: 00007fb943ffb040 R14: 0000000000000000 R15: 00007fb943ffd260 [726.331693] </TASK> While we debug the issue, we found running fstests generic/551 on 5GB non-zoned null_blk device in the emulated zoned mode also had a similar hung issue. Also, we can reproduce the same symptom with an error injected cow_file_range() setup. The hang occurs when cow_file_range() fails in the middle of allocation. cow_file_range() called from do_allocation_zoned() can split the give region ([start, end]) for allocation depending on current block group usages. When btrfs can allocate bytes for one part of the split regions but fails for the other region (e.g. because of -ENOSPC), we return the error leaving the pages in the succeeded regions locked. Technically, this occurs only when @unlock == 0. Otherwise, we unlock the pages in an allocated region after creating an ordered extent. Considering the callers of cow_file_range(unlock=0) won't write out the pages, we can unlock the pages on error exit from cow_file_range(). So, we can ensure all the pages except @locked_page are unlocked on error case. In summary, cow_file_range now behaves like this: - page_started == 1 (return value) - All the pages are unlocked. IO is started. - unlock == 1 - All the pages except @locked_page are unlocked in any case - unlock == 0 - On success, all the pages are locked for writing out them - On failure, all the pages except @locked_page are unlocked
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
NVD-CWE-noinfo

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: coresight: tmc-etr: Fix race condition between sysfs and perf mode When trying to run perf and sysfs mode simultaneously, the WARN_ON() in tmc_etr_enable_hw() is triggered sometimes: WARNING: CPU: 42 PID: 3911571 at drivers/hwtracing/coresight/coresight-tmc-etr.c:1060 tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] [..snip..] Call trace: tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] (P) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] (L) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] coresight_enable_path+0x1c8/0x218 [coresight] coresight_enable_sysfs+0xa4/0x228 [coresight] enable_source_store+0x58/0xa8 [coresight] dev_attr_store+0x20/0x40 sysfs_kf_write+0x4c/0x68 kernfs_fop_write_iter+0x120/0x1b8 vfs_write+0x2c8/0x388 ksys_write+0x74/0x108 __arm64_sys_write+0x24/0x38 el0_svc_common.constprop.0+0x64/0x148 do_el0_svc+0x24/0x38 el0_svc+0x3c/0x130 el0t_64_sync_handler+0xc8/0xd0 el0t_64_sync+0x1ac/0x1b0 ---[ end trace 0000000000000000 ]--- Since the enablement of sysfs mode is separeted into two critical regions, one for sysfs buffer allocation and another for hardware enablement, it's possible to race with the perf mode. Fix this by double check whether the perf mode's been used before enabling the hardware in sysfs mode. mode: [sysfs mode] [perf mode] tmc_etr_get_sysfs_buffer() spin_lock(&drvdata->spinlock) [sysfs buffer allocation] spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() drvdata->etr_buf = etr_perf->etr_buf spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() WARN_ON(drvdata->etr_buf) // WARN sicne etr_buf initialized at the perf side spin_unlock(&drvdata->spinlock) With this fix, we retain the check for CS_MODE_PERF in get_etr_sysfs_buf. This ensures we verify whether the perf mode's already running before we actually allocate the buffer. Then we can save the time of allocating/freeing the sysfs buffer if race with the perf mode.CVE-2026-46272