Re: [PATCH net-next V2] ptp: fix corrupted list in ptp_open

[Richard Cochran]

On Thu, Nov 02, 2023 at 02:16:54PM -0400, Jeremy Cline wrote:

> While this patch looks to cover adding and removing items from the list,
> the code that iterates over the list isn't covered which can be
> problematic. If the list is modified while it is being iterated, the
> iterating code could chase an invalid pointer.

Indeed.

See ptp_clock.c:

 416         case PTP_CLOCK_EXTTS:
 417                 /* Enqueue timestamp on selected queues */
 418                 list_for_each_entry(tsevq, &ptp->tsevqs, qlist) {
 419                         if (test_bit((unsigned int)event->index, tsevq->mask))
 420                                 enqueue_external_timestamp(tsevq, event);
 421                 }
 422                 wake_up_interruptible(&ptp->tsev_wq);
 423                 break;

Thanks,
Richard