| From bippy-1.2.0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@kernel.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-22127: f2fs: fix potential deadloop in prepare_compress_overwrite() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| f2fs: fix potential deadloop in prepare_compress_overwrite() |
| |
| Jan Prusakowski reported a kernel hang issue as below: |
| |
| When running xfstests on linux-next kernel (6.14.0-rc3, 6.12) I |
| encountered a problem in generic/475 test where fsstress process |
| gets blocked in __f2fs_write_data_pages() and the test hangs. |
| The options I used are: |
| |
| MKFS_OPTIONS -- -O compression -O extra_attr -O project_quota -O quota /dev/vdc |
| MOUNT_OPTIONS -- -o acl,user_xattr -o discard,compress_extension=* /dev/vdc /vdc |
| |
| INFO: task kworker/u8:0:11 blocked for more than 122 seconds. |
| Not tainted 6.14.0-rc3-xfstests-lockdep #1 |
| "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. |
| task:kworker/u8:0 state:D stack:0 pid:11 tgid:11 ppid:2 task_flags:0x4208160 flags:0x00004000 |
| Workqueue: writeback wb_workfn (flush-253:0) |
| Call Trace: |
| <TASK> |
| __schedule+0x309/0x8e0 |
| schedule+0x3a/0x100 |
| schedule_preempt_disabled+0x15/0x30 |
| __mutex_lock+0x59a/0xdb0 |
| __f2fs_write_data_pages+0x3ac/0x400 |
| do_writepages+0xe8/0x290 |
| __writeback_single_inode+0x5c/0x360 |
| writeback_sb_inodes+0x22f/0x570 |
| wb_writeback+0xb0/0x410 |
| wb_do_writeback+0x47/0x2f0 |
| wb_workfn+0x5a/0x1c0 |
| process_one_work+0x223/0x5b0 |
| worker_thread+0x1d5/0x3c0 |
| kthread+0xfd/0x230 |
| ret_from_fork+0x31/0x50 |
| ret_from_fork_asm+0x1a/0x30 |
| </TASK> |
| |
| The root cause is: once generic/475 starts toload error table to dm |
| device, f2fs_prepare_compress_overwrite() will loop reading compressed |
| cluster pages due to IO error, meanwhile it has held .writepages lock, |
| it can block all other writeback tasks. |
| |
| Let's fix this issue w/ below changes: |
| - add f2fs_handle_page_eio() in prepare_compress_overwrite() to |
| detect IO error. |
| - detect cp_error earler in f2fs_read_multi_pages(). |
| |
| The Linux kernel CVE team has assigned CVE-2025-22127 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.6 with commit 4c8ff7095bef64fc47e996a938f7d57f9e077da3 and fixed in 6.14.2 with commit 7215cf8ef54bdc9082dffac4662416d54961e258 |
| Issue introduced in 5.6 with commit 4c8ff7095bef64fc47e996a938f7d57f9e077da3 and fixed in 6.15 with commit 3147ee567dd9004a49826ddeaf0a4b12865d4409 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2025-22127 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| fs/f2fs/compress.c |
| fs/f2fs/data.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/7215cf8ef54bdc9082dffac4662416d54961e258 |
| https://git.kernel.org/stable/c/3147ee567dd9004a49826ddeaf0a4b12865d4409 |
