fsnotify: clear PARENT_WATCHED flags lazily
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 5.10.226, 5.15.167, 6.1.109, 6.6.50, 6.10.9
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- Linux Linux
From 873feea09ebc980cbd3631b767356ce1eee65ec1 · fixed in 3f3ef1d9f66b93913ce2171120d9226b55acd41d; From 873feea09ebc980cbd3631b767356ce1eee65ec1 · fixed in f9a48bc3dd9099935751458a5bbbea4b7c28abc8; From 873feea09ebc980cbd3631b767356ce1eee65ec1 · fixed in d8c42405fc3507cc43ba7e4986a773c3fc633f6e; From 873feea09ebc980cbd3631b767356ce1eee65ec1 · fixed in fc1b1e135c3f72382f792e6c319fc088d5523ad5; From 873feea09ebc980cbd3631b767356ce1eee65ec1 · fixed in 7ef1d2e240c32b1f337a37232d037b07e3919e1a; From 873feea09ebc980cbd3631b767356ce1eee65ec1 · fixed in 172e422ffea20a89bfdc672741c1aad6fbb5044e
- Linux Linux
2.6.38
- KernelLinux
From 2.6.38 · fixed in 5.10.226; From 5.11.0 · fixed in 5.15.167; From 5.16.0 · fixed in 6.1.109; From 6.2.0 · fixed in 6.6.50; From 6.7.0 · fixed in 6.10.9