eventfs: Use children field for rcu head and add memory barriers

Summary

In the Linux kernel, the following vulnerability has been resolved: eventfs: Use children field for rcu head and add memory barriers When an eventfs inode is freed, it sets ei->is_freed and then uses its ei->list to add it to the srcu link list as the list field is a union with the rcu list head. As the ei->list is used to iterate over an SRCU protected list without taking the eventfs_mutex, there's nothing stopping the iteration over that list to see the ei->rcu instead of the ei->list and it will read a corrupt target. To fix this, change the union of the rcu list head with the children list. On freeing the eventfs inode, set the is_free and execute a smp_wmb() before adding the eventfs inode to the SRCU list. On iteration of the ei->children list, at the start, execute a smp_rmb() and then read the is_freed of the ei to see if the children list is still valid. If is_freed is set, then the ei_child read is not valid and the loop should exit immediately.

Timeline

1. Aug 22, 2026, 3:31 PM UTCCVE published
2. Oct 21, 2026, 12:46 PM UTCRecord last updated

Affected versions

• Linux Linux

  From f3f41f444b321ec393edbc251e024fd62658ce55 · fixed in 25d27d5fa8645ab61018c3efec5c69f49280ca7d; From 704f960dbee2f1634f4b4e16f208cb16eaf41c1e · fixed in 1b95382da85cff3bf0f922ff0275f186abdadfce; From 704f960dbee2f1634f4b4e16f208cb16eaf41c1e · fixed in 2b80707b9e27671e10840d17c6f8f774c4ad9847; From 704f960dbee2f1634f4b4e16f208cb16eaf41c1e · fixed in 004f7232e49730448f91665e76bdd7dff8e0c638; From 704f960dbee2f1634f4b4e16f208cb16eaf41c1e · fixed in f0ece16ffca7384787b692431961ce202907acf5; From 6.6.18 · fixed in 6.6.160; From 6.7.6 · fixed in 6.8

• Linux Linux

  6.8

• KernelLinux

  fixed in 6.6.160; From 6.7.0 · fixed in 6.12.114; From 6.8.0 · fixed in 6.18.57; From 6.13.0 · fixed in 7.1.9

References 5