CVE-2025-39782

/// Technical description

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

jbd2: prevent softlockup in jbd2_log_do_checkpoint()

Both jbd2_log_do_checkpoint() and jbd2_journal_shrink_checkpoint_list()

periodically release j_list_lock after processing a batch of buffers to

avoid long hold times on the j_list_lock. However, since both functions

contend for j_list_lock, the combined time spent waiting and processing

can be significant.

jbd2_journal_shrink_checkpoint_list() explicitly calls cond_resched() when

need_resched() is true to avoid softlockups during prolonged operations.

But jbd2_log_do_checkpoint() only exits its loop when need_resched() is

true, relying on potentially sleeping functions like __flush_batch() or

wait_on_buffer() to trigger rescheduling. If those functions do not sleep,

the kernel may hit a softlockup.

watchdog: BUG: soft lockup - CPU#3 stuck for 156s! [kworker/u129:2:373]

CPU: 3 PID: 373 Comm: kworker/u129:2 Kdump: loaded Not tainted 6.6.0+ #10

Hardware name: Huawei

/// 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