Deadlock The advisory has been revoked - it doesn't affect any version of package kernel-modules-internal  (opens in a new tab)


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  • Snyk IDSNYK-RHEL10-KERNELMODULESINTERNAL-22086537
  • published31 Oct 2026
  • disclosed15 Aug 2026

Introduced: 15 Aug 2026

CVE-2026-74307  (opens in a new tab)
CWE-833  (opens in a new tab)

Amendment

The Red Hat security team deemed this advisory irrelevant for RHEL:10.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-modules-internal package and not the kernel-modules-internal package as distributed by RHEL.

In the Linux kernel, the following vulnerability has been resolved:

ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT

Reject the EXT4_IOC_MOVE_EXT ioctl early if the donor file does not belong to the same superblock as the original file. Currently, this validation is performed inside ext4_move_extents() by mext_check_validity(), but only after lock_two_nondirectories() has already acquired the inode locks. When the donor fd refers to a file on a different filesystem (e.g., overlayfs), this late validation creates a circular lock dependency:

CPU0 (overlayfs write) CPU1 (ext4 ioctl)


inode_lock(ovl_inode) mnt_want_write_file(filp) sb_start_write(ext4_sb) [sb_writers] backing_file_write_iter() vfs_iter_write(real_file) file_start_write(real_file) sb_start_write(ext4_sb) [blocked by freeze] lock_two_nondirectories() inode_lock(ovl_inode) [blocked]

With a concurrent freeze operation holding sb_writers write side, this forms a deadlock cycle: CPU0 waits for freeze to complete, freeze waits for CPU1's sb_writers reader to exit, CPU1 waits for CPU0's inode lock.

Since EXT4_IOC_MOVE_EXT exchanges physical extents between two files, it fundamentally requires both files to reside on the same ext4 filesystem. Moving the superblock check before any lock acquisition is both semantically correct and eliminates the circular dependency by ensuring that cross-filesystem donor fds are rejected before sb_writers or inode locks are taken.