CVE-2024-50006

/// Technical description

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

ext4: fix i_data_sem unlock order in ext4_ind_migrate()

Fuzzing reports a possible deadlock in jbd2_log_wait_commit.

This issue is triggered when an EXT4_IOC_MIGRATE ioctl is set to require

synchronous updates because the file descriptor is opened with O_SYNC.

This can lead to the jbd2_journal_stop() function calling

jbd2_might_wait_for_commit(), potentially causing a deadlock if the

EXT4_IOC_MIGRATE call races with a write(2) system call.

This problem only arises when CONFIG_PROVE_LOCKING is enabled. In this

case, the jbd2_might_wait_for_commit macro locks jbd2_handle in the

jbd2_journal_stop function while i_data_sem is locked. This triggers

lockdep because the jbd2_journal_start function might also lock the same

jbd2_handle simultaneously.

Found by Linux Verification Center (linuxtesting.org) with syzkaller.

Rule: add

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References