CVE-2024-27058: tmpfs: fix race on handling dquot rbtree

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-01 · updated 2026-08-04
Weakness: CWE-362

Description

In the Linux kernel, the following vulnerability has been resolved: tmpfs: fix race on handling dquot rbtree A syzkaller reproducer found a race while attempting to remove dquot information from the rb tree. Fetching the rb_tree root node must also be protected by the dqopt->dqio_sem, otherwise, giving the right timing, shmem_release_dquot() will trigger a warning because it couldn't find a node in the tree, when the real reason was the root node changing before the search starts: Thread 1 Thread 2 - shmem_release_dquot() - shmem_{acquire,release}_dquot() - fetch ROOT - Fetch ROOT - acquire dqio_sem - wait dqio_sem - do something, triger a tree rebalance - release dqio_sem - acquire dqio_sem - start searching for the node, but from the wrong location, missing the node, and triggering a warning.

Affected products

Linux kernel: from 6.6 before 6.6.24; from 6.7 before 6.7.12; from 6.8 before 6.8.3; 6.9-rc1 — fixed in 6.6.24, 6.7.12, 6.8.3

How to fix

Upgrade to a fixed version: Linux kernel 6.6.24, 6.7.12, 6.8.3. Check the vendor advisory for mitigations.

References

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