CVE-2025-68336

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

locking/spinlock/debug: Fix data-race in do_raw_write_lock

KCSAN reports:

BUG: KCSAN: data-race in do_raw_write_lock / do_raw_write_lock

write (marked) to 0xffff800009cf504c of 4 bytes by task 1102 on cpu 1: do_raw_write_lock+0x120/0x204 _raw_write_lock_irq do_exit call_usermodehelper_exec_async ret_from_fork

read to 0xffff800009cf504c of 4 bytes by task 1103 on cpu 0: do_raw_write_lock+0x88/0x204 _raw_write_lock_irq do_exit call_usermodehelper_exec_async ret_from_fork

value changed: 0xffffffff -> 0x00000001

Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 1103 Comm: kworker/u4:1 6.1.111

Commit 1a365e822372 (locking/spinlock/debug: Fix various data races) has adressed most of these races, but seems to be not consistent/not complete.

From do_raw_write_lock() only debug_write_lock_after() part has been converted to WRITE_ONCE(), but not debug_write_lock_before() part. Do it now.

Affected Software

References

• https://git.kernel.org/stable/c/16b3590c0e1e615757dade098c8fbc0d4f040c76
• https://git.kernel.org/stable/c/396a9270a7b90886be501611b13aa636f2e8c703
• https://git.kernel.org/stable/c/b163a5e8c703201c905d6ec7920ed79d167e8442
• https://git.kernel.org/stable/c/c14ecb555c3ee80eeb030a4e46d00e679537f03a