Description
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.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
873feea09ebc980cbd3631b767356ce1eee65ec1 to < 3f3ef1d9f66b93913ce2171120d9226b55acd41daffected873feea09ebc980cbd3631b767356ce1eee65ec1 to < f9a48bc3dd9099935751458a5bbbea4b7c28abc8affected873feea09ebc980cbd3631b767356ce1eee65ec1 to < d8c42405fc3507cc43ba7e4986a773c3fc633f6eaffected873feea09ebc980cbd3631b767356ce1eee65ec1 to < fc1b1e135c3f72382f792e6c319fc088d5523ad5affected873feea09ebc980cbd3631b767356ce1eee65ec1 to < 7ef1d2e240c32b1f337a37232d037b07e3919e1aaffected873feea09ebc980cbd3631b767356ce1eee65ec1 to < 172e422ffea20a89bfdc672741c1aad6fbb5044eaffected
Linux Linux
Default version status: affected
2.6.38affected0 to < 2.6.38unaffected5.10.226 to ≤ 5.10.*unaffected5.15.167 to ≤ 5.15.*unaffected6.1.109 to ≤ 6.1.*unaffected6.6.50 to ≤ 6.6.*unaffected6.10.9 to ≤ 6.10.*unaffected6.11 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/3f3ef1d9f66b93913ce2171120d9226b55acd41d ↗
- https://git.kernel.org/stable/c/f9a48bc3dd9099935751458a5bbbea4b7c28abc8 ↗
- https://git.kernel.org/stable/c/d8c42405fc3507cc43ba7e4986a773c3fc633f6e ↗
- https://git.kernel.org/stable/c/fc1b1e135c3f72382f792e6c319fc088d5523ad5 ↗
- https://git.kernel.org/stable/c/7ef1d2e240c32b1f337a37232d037b07e3919e1a ↗
- https://git.kernel.org/stable/c/172e422ffea20a89bfdc672741c1aad6fbb5044e ↗
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html ↗
- https://cert-portal.siemens.com/productcert/html/ssa-265688.html ↗
- https://cert-portal.siemens.com/productcert/html/ssa-355557.html ↗