CVE-2026-72368: cachefiles: Fix double unlock in nomem_d_alloc error path

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-15 · updated 2026-08-17

Description

In the Linux kernel, the following vulnerability has been resolved: cachefiles: Fix double unlock in nomem_d_alloc error path When start_creating() fails and returns -ENOMEM, it has already released the parent directory lock in __start_dirop(): static struct dentry *__start_dirop(...) { ... inode_lock_nested(dir, I_MUTEX_PARENT); dentry = lookup_one_qstr_excl(name, parent, lookup_flags); if (IS_ERR(dentry)) inode_unlock(dir); <-- Lock released on error return dentry; } However, the nomem_d_alloc error path in cachefiles_get_directory() unconditionally calls inode_unlock(d_inode(dir)) again, causing a double unlock that corrupts the rwsem state. This is a leftover from commit 7ab96df840e60 which replaced manual locking with start_creating() but failed to update the nomem_d_alloc path (while correctly updating mkdir_error and lookup_error paths).

Affected products

Linux kernel: 6.19 — fixed in 7.2

How to fix

Upgrade to a fixed version: Linux kernel 7.2. Check the vendor advisory for mitigations.

References

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