CVE-2024-47660: fsnotify: clear PARENT_WATCHED flags lazily
First published: Wed Oct 09 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: fsnotify: clear PARENT_WATCHED flags lazily In some setups directories can have many (usually negative) dentries. Hence __fsnotify_update_child_dentry_flags() function can take a significant amount of time. Since the bulk of this function happens under inode->i_lock this causes a significant contention on the lock when we remove the watch from the directory as the __fsnotify_update_child_dentry_flags() call from fsnotify_recalc_mask() races with __fsnotify_update_child_dentry_flags() calls from __fsnotify_parent() happening on children. This can lead upto softlockup reports reported by users. Fix the problem by calling fsnotify_update_children_dentry_flags() to set PARENT_WATCHED flags only when parent starts watching children. When parent stops watching children, clear false positive PARENT_WATCHED flags lazily in __fsnotify_parent() for each accessed child.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Linux kernel | <5.10.226 | |
| Linux Linux kernel | >=5.11<5.15.167 | |
| Linux Linux kernel | >=5.16<6.1.109 | |
| Linux Linux kernel | >=6.2<6.6.50 | |
| Linux Linux kernel | >=6.7<6.10.9 | |
| debian/linux | <=5.10.223-1<=5.10.226-1 | 6.1.115-1 6.1.112-1 6.11.7-1 6.11.9-1 |
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
- https://git.kernel.org/stable/c/172e422ffea20a89bfdc672741c1aad6fbb5044e
- https://git.kernel.org/stable/c/3f3ef1d9f66b93913ce2171120d9226b55acd41d
- https://git.kernel.org/stable/c/7ef1d2e240c32b1f337a37232d037b07e3919e1a
- https://git.kernel.org/stable/c/d8c42405fc3507cc43ba7e4986a773c3fc633f6e
- https://git.kernel.org/stable/c/f9a48bc3dd9099935751458a5bbbea4b7c28abc8
- https://git.kernel.org/stable/c/fc1b1e135c3f72382f792e6c319fc088d5523ad5
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-47660
- https://nvd.nist.gov/vuln/detail/CVE-2024-47660
- https://launchpad.net/bugs/cve/CVE-2024-47660
- https://security-tracker.debian.org/tracker/CVE-2024-47660
- https://ubuntu.com/security/CVE-2024-47660
- https://git.kernel.org/linus/172e422ffea20a89bfdc672741c1aad6fbb5044e
- agent/title
- agent/first-publish-date
- agent/type
- collector/nvd-api
- source/NVD
- agent/software-canonical-lookup
- agent/remedy
- agent/severity
- agent/weakness
- collector/mitre-cve
- source/MITRE
- agent/last-modified-date
- agent/references
- agent/author
- agent/softwarecombine
- agent/tags
- collector/nvd-cve
- collector/usn-cve
- source/Ubuntu
- agent/description
- agent/event
- collector/security-tracker-debian
- source/Debian
- vendor/linux
- canonical/linux linux kernel
- version/linux linux kernel/5.11
- version/linux linux kernel/5.16
- version/linux linux kernel/6.2
- version/linux linux kernel/6.7
- package-manager/debian