ext4: don't BUG if someone dirty pages without asking ext4 first

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2022-49171
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-02-26 07:00:54 UTC
Updated2026-11-05 20:16:59 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: ext4: don't BUG if someone dirty pages without asking ext4 first [un]pin_user_pages_remote is dirtying pages without properly warning the file system in advance. A related race was noted by Jan Kara in 2018[1]; however, more recently instead of it being a very hard-to-hit race, it could be reliably triggered by process_vm_writev(2) which was discovered by Syzbot[2]. This is technically a bug in mm/gup.c, but arguably ext4 is fragile in that if some other kernel subsystem dirty pages without properly notifying the file system using page_mkwrite(), ext4 will BUG, while other file systems will not BUG (although data will still be lost). So instead of crashing with a BUG, issue a warning (since there may be potential data loss) and just mark the page as clean to avoid unprivileged denial of service attacks until the problem can be properly fixed. More discussion and background can be found in the thread starting at [2]. [1] https://lore.kernel.org/linux-mm/[email protected] [2] https://lore.kernel.org/r/[email protected]

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-617

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected a42afc5f56f319107e987aa6adf2f65d93d527c7 5db60e76edf5680ff1f3a7221036fc44b308f146 git Not specified
CNA Linux Linux affected a42afc5f56f319107e987aa6adf2f65d93d527c7 d666dfaa571465a19f014534a214c255ea33f301 git Not specified
CNA Linux Linux affected a42afc5f56f319107e987aa6adf2f65d93d527c7 0d3a6926f7e8be3c897fa46216ce13b119a9f56a git Not specified
CNA Linux Linux affected a42afc5f56f319107e987aa6adf2f65d93d527c7 5a016c053f426a73752c3b41b60b497b58694d48 git Not specified
CNA Linux Linux affected a42afc5f56f319107e987aa6adf2f65d93d527c7 330d0e44fc5a47c27df958ecdd4693a3cb1d8b81 git Not specified
CNA Linux Linux affected a42afc5f56f319107e987aa6adf2f65d93d527c7 a0856764dc1276ad2dc7891288c2e9246bf11a37 git Not specified
CNA Linux Linux affected a42afc5f56f319107e987aa6adf2f65d93d527c7 343117559ef41e992e326f7a92da1a8f254dfa8c git Not specified
CNA Linux Linux affected a42afc5f56f319107e987aa6adf2f65d93d527c7 677c9d30e8487bee6c8e3b034070319d98f6e203 git Not specified
CNA Linux Linux affected a42afc5f56f319107e987aa6adf2f65d93d527c7 cc5095747edfb054ca2068d01af20be3fcc3634f git Not specified
CNA Linux Linux affected 2.6.37 Not specified
CNA Linux Linux unaffected 2.6.37 semver Not specified
CNA Linux Linux unaffected 4.9.311 4.9.* semver Not specified
CNA Linux Linux unaffected 4.14.276 4.14.* semver Not specified
CNA Linux Linux unaffected 4.19.238 4.19.* semver Not specified
CNA Linux Linux unaffected 5.4.189 5.4.* semver Not specified
CNA Linux Linux unaffected 5.10.110 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.33 5.15.* semver Not specified
CNA Linux Linux unaffected 5.16.19 5.16.* semver Not specified
CNA Linux Linux unaffected 5.17.2 5.17.* semver Not specified
CNA Linux Linux unaffected 5.18 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/d666dfaa571465a19f014534a214c255ea33f301 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/5db60e76edf5680ff1f3a7221036fc44b308f146 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/5a016c053f426a73752c3b41b60b497b58694d48 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/343117559ef41e992e326f7a92da1a8f254dfa8c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/330d0e44fc5a47c27df958ecdd4693a3cb1d8b81 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/677c9d30e8487bee6c8e3b034070319d98f6e203 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/a0856764dc1276ad2dc7891288c2e9246bf11a37 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/0d3a6926f7e8be3c897fa46216ce13b119a9f56a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/cc5095747edfb054ca2068d01af20be3fcc3634f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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