CVE-2022-50126: jbd2: fix assertion 'jh->b_frozen_data == NULL' failure when journal aborted

Vulnerability summary

CVE-2022-50126 is a medium (CVSS 5.5) Reachable Assertion vulnerability in linux. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 9.1% of scored vulnerabilities.

Timeline

1. 18-06-2025
   PublishedVulnerability first disclosed.
2. 11-05-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: jbd2: fix assertion 'jh->b_frozen_data == NULL' failure when journal aborted Following process will fail assertion 'jh->b_frozen_data == NULL' in jbd2_journal_dirty_metadata(): jbd2_journal_commit_transaction unlink(dir/a) jh->b_transaction = trans1 jh->b_jlist = BJ_Metadata journal->j_running_transaction = NULL trans1->t_state = T_COMMIT unlink(dir/b) handle->h_trans = trans2 do_get_write_access jh->b_modified = 0 jh->b_frozen_data = frozen_buffer jh->b_next_transaction = trans2 jbd2_journal_dirty_metadata is_handle_aborted is_journal_aborted // return false --> jbd2 abort <-- while (commit_transaction->t_buffers) if (is_journal_aborted) jbd2_journal_refile_buffer __jbd2_journal_refile_buffer WRITE_ONCE(jh->b_transaction, jh->b_next_transaction) WRITE_ONCE(jh->b_next_transaction, NULL) __jbd2_journal_file_buffer(jh, BJ_Reserved) J_ASSERT_JH(jh, jh->b_frozen_data == NULL) // assertion failure ! The reproducer (See detail in [Link]) reports: ------------[ cut here ]------------ kernel BUG at fs/jbd2/transaction.c:1629! invalid opcode: 0000 [#1] PREEMPT SMP CPU: 2 PID: 584 Comm: unlink Tainted: G W 5.19.0-rc6-00115-g4a57a8400075-dirty #697 RIP: 0010:jbd2_journal_dirty_metadata+0x3c5/0x470 RSP: 0018:ffffc90000be7ce0 EFLAGS: 00010202 Call Trace: <TASK> __ext4_handle_dirty_metadata+0xa0/0x290 ext4_handle_dirty_dirblock+0x10c/0x1d0 ext4_delete_entry+0x104/0x200 __ext4_unlink+0x22b/0x360 ext4_unlink+0x275/0x390 vfs_unlink+0x20b/0x4c0 do_unlinkat+0x42f/0x4c0 __x64_sys_unlink+0x37/0x50 do_syscall_64+0x35/0x80 After journal aborting, __jbd2_journal_refile_buffer() is executed with holding @jh->b_state_lock, we can fix it by moving 'is_handle_aborted()' into the area protected by @jh->b_state_lock.

• CWE-617Reachable AssertionThe product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.