DEBIAN-CVE-2026-92502

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Source

https://security-tracker.debian.org/tracker/CVE-2026-92502

Import Source

https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-92502.json

JSON Data

https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-92502

Upstream

CVE-2026-92502

Published

2026-09-17T17:17:52Z

Modified

2026-09-18T05:01:35Z

Summary

[none]

Details

In the Linux kernel, the following vulnerability has been resolved: ext4: clear stale xarray tags on folios skipped during writeback In data=journal mode, the writeback thread can hit the WARN_ON_ONCE(sb_rdonly(sb)) in ext4_journal_check_start() while the superblock is being remounted read-only during reboot: Workqueue: writeback wb_workfn (flush-253:0) RIP: 0010:ext4_journal_check_start+0x8b/0xd0 Call Trace: __ext4_journal_start_sb+0x3c/0x1e0 mpage_prepare_extent_to_map+0x4af/0x580 ext4_do_writepages+0x3c0/0x1080 ext4_writepages+0xc8/0x1a0 do_writepages+0xc4/0x180 __writeback_single_inode+0x45/0x2f0 writeback_sb_inodes+0x26b/0x5d0 __writeback_inodes_wb+0x54/0x100 wb_writeback+0x1ac/0x320 wb_workfn+0x394/0x470 And followed by the warning: EXT4-fs warning (device vda1): ext4_evict_inode:195: inode #6263: comm (sd-umount): data will be lost This issue is not reproduced every time, but frequently. The reproduction step is to create a VM with 8 CPUs, 16G memory and setup data=journal: sudo tune2fs -o journal_data /dev/vda1 Run fio: rm -f fiotest fio --name=fiotest --rw=randwrite --bs=4k --runtime=6 --ioengine=libaio --iodepth=256 --numjobs=8 --filename=fiotest --filesize=30G --group_reporting Reboot the VM, and check the console output from: virsh console testvm But there is no dirty inode, folio_clear_dirty_for_io clears PG_dirty but leaves tags PAGECACHE_TAG_DIRTY and PAGECACHE_TAG_TOWRITE set which are only cleared by __folio_start_writeback. In data=journal mode, jbd2 checkpoints the journalled data to its final location and clears its own dirty flag without touching folio PG_dirty or xarray dirty flags. The commit f4a2b42e7891 ("ext4: fix stale xarray tags after writeback") fixes when PG_dirty is still set but there is no dirty page. Another case is PG_dirty is cleared, but PAGECACHE_TAG_DIRTY and PAGECACHE_TAG_TOWRITE is still set. In this case, writeback thread checks clean folio and skips it in mpage_prepare_extent_to_map: if (!folio_test_dirty(folio) || ... folio_unlcok(folio); continue And never reaches ext4_bio_write_folio where the commit f4a2b42e7891 clears the stale xarray tags. Print debug logs after the filesystem is remounted read-only: writepages RDONLY nrpages=2048 dirtytag=1 wbtag=0 towrite=1 sync=0 And all folios are actually clean: folio idx=3 dirty=0 wb=0 checked=0 dirtybuf=0 jbddirty=0 mapped=1 ... We need to clear the xarray stale tags for such clean folios by cycling them through writeback in the skip path, the same way f4a2b42e7891 does in ext4_bio_write_folio.

References

https://security-tracker.debian.org/tracker/CVE-2026-92502

Affected packages

Debian:13 / linux

Package

Name: linux
Purl: pkg:deb/debian/linux?arch=source&distro=trixie

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Affected versions

6.*

6.12.38-1

6.12.41-1

6.12.43-1~bpo12+1

6.12.43-1

6.12.48-1

6.12.57-1~bpo12+1

6.12.57-1

6.12.63-1~bpo12+1

6.12.63-1

6.12.69-1~bpo12+1

6.12.69-1

6.12.73-1~bpo12+1

6.12.73-1

6.12.74-1

6.12.74-2~bpo12+1

6.12.74-2

6.12.85-1~bpo12+1

6.12.85-1

6.12.86-1~bpo12+1

6.12.86-1

6.12.88-1~bpo12+1

6.12.88-1

6.12.90-1~bpo12+1

6.12.90-1

6.12.90-2~bpo12+1

6.12.90-2

6.12.94-1~bpo12+1

6.12.94-1

6.12.95-1~bpo12+1

6.12.95-1

6.12.96-1

6.12.100-1

6.12.101-1

6.12.105-1

6.12.107-1

6.13~rc6-1~exp1

6.13~rc7-1~exp1

6.13.2-1~exp1

6.13.3-1~exp1

6.13.4-1~exp1

6.13.5-1~exp1

6.13.6-1~exp1

6.13.7-1~exp1

6.13.8-1~exp1

6.13.9-1~exp1

6.13.10-1~exp1

6.13.11-1~exp1

6.14.3-1~exp1

6.14.5-1~exp1

6.14.6-1~exp1

6.15~rc7-1~exp1

6.15-1~exp1

6.15.1-1~exp1

6.15.2-1~exp1

6.15.3-1~exp1

6.15.4-1~exp1

6.15.5-1~exp1

6.15.6-1~exp1

6.16~rc7-1~exp1

6.16-1~exp1

6.16.1-1~exp1

6.16.3-1~bpo13+1

6.16.3-1

6.16.5-1

6.16.6-1

6.16.7-1

6.16.8-1

6.16.9-1

6.16.10-1

6.16.11-1

6.16.12-1~bpo13+1

6.16.12-1

6.16.12-2

6.17.2-1~exp1

6.17.5-1~exp1

6.17.6-1

6.17.7-1

6.17.7-2

6.17.8-1~bpo13+1

6.17.8-1

6.17.9-1

6.17.10-1

6.17.11-1

6.17.12-1

6.17.13-1~bpo13+1

6.17.13-1

6.18~rc4-1~exp1

6.18~rc4-1~exp2

6.18~rc5-1~exp1

6.18~rc6-1~exp1

6.18~rc7-1~exp1

6.18.1-1~exp1

6.18.2-1~exp1

6.18.3-1

6.18.5-1~bpo13+1

6.18.5-1

6.18.8-1

6.18.9-1~bpo13+1

6.18.9-1

6.18.10-1

6.18.12-1~bpo13+1

6.18.12-1

6.18.13-1

6.18.14-1

6.18.15-1~bpo13+1

6.18.15-1

6.19~rc4-1~exp1

6.19~rc5-1~exp1

6.19~rc6-1~exp1

6.19~rc7-1~exp1

6.19~rc8-1~exp1

6.19-1~exp1

6.19.2-1~exp1

6.19.3-1~exp1

6.19.4-1~exp1

6.19.5-1~exp1

6.19.6-1

6.19.6-2~bpo13+1

6.19.6-2

6.19.8-1~bpo13+1

6.19.8-1

6.19.10-1~bpo13+1

6.19.10-1

6.19.11-1~bpo13+1

6.19.11-1

6.19.12-1

6.19.13-1~bpo13+1

6.19.13-1

6.19.14-1~bpo13+1

6.19.14-1

7.*

7.0-1~exp1

7.0.1-1~exp1

7.0.3-1

7.0.4-1~bpo13+1

7.0.4-1

7.0.7-1~bpo13+1

7.0.7-1

7.0.9-1~bpo13+1

7.0.9-1

7.0.10-1~bpo13+1

7.0.10-1

7.0.12-1

7.0.12-2~bpo13+1

7.0.12-2

7.0.13-1~bpo13+1

7.0.13-1

7.0.14-1

7.1~rc2-1~exp1

7.1~rc3-1~exp1

7.1~rc4-1~exp1

7.1~rc4-1~exp2

7.1~rc5-1~exp1

7.1~rc7-1~exp1

7.1.1-1~exp1

7.1.2-1~exp1

7.1.3-1~bpo13+1

7.1.3-1

7.1.3-1+sunvdc

7.1.4-1

7.1.5-1

7.1.6-1

7.1.7-1~bpo13+1

7.1.7-1

7.1.8-1~bpo13+1

7.1.8-1

7.1.8-2

7.1.9-1

7.1.9-1+sparc64

7.1.10-1

7.1.12-1

7.1.13-1

7.2~rc3-1~exp1

7.2~rc5-1~exp1

7.2~rc7-1~exp1

7.2.2-1~exp1

7.2.3-1~exp1

7.2.6-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}

Database specific

source

"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-92502.json"

Debian:14 / linux