Medium · published October 21, 2024
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
| Product | Versions | Fixed in |
|---|---|---|
| linux/linux_kernel | < 5.10.227 | 5.10.227 |
| linux/linux_kernel | ≥ 5.11, < 5.15.168 | 5.15.168 |
| linux/linux_kernel | ≥ 5.16, < 6.1.113 | 6.1.113 |
| linux/linux_kernel | ≥ 6.2, < 6.6.55 | 6.6.55 |
| linux/linux_kernel | ≥ 6.7, < 6.10.14 | 6.10.14 |
| linux/linux_kernel | ≥ 6.11, < 6.11.3 | 6.11.3 |