On Tue, 22 Oct 2024 12:09:47 +0300
Dan Carpenter <[email protected]> wrote:
> Hello Petr Pavlu,
It's not Petr's fault, but mine.
>
> Commit 1f1c2bc9d075 ("ring-buffer: Limit time with disabled
> interrupts in rb_check_pages()") from Jul 15, 2024 (linux-next),
> leads to the following Smatch static checker warning:
>
> 1531 raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
> 1532 head = rb_list_head(cpu_buffer->pages);
> 1533 if (!rb_check_links(cpu_buffer, head))
> 1534 goto out_locked;
> 1535 buffer_cnt = cpu_buffer->cnt;
> 1536 tmp = head;
> 1537 raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
> 1538 return;
> ^^^^^^
> You probably intended to delete this return?
He sent two patches where the second patch was a fix to mainline. I
asked him to reverse the order so I could send the fix to Linus, in
which he did. In the mean time I switched the order myself for testing
and broke it with this mistake. When he sent the update I took his
patches but accidentally tested and pushed the broken branch to
linux-next.
When Linus took the fix, Stephen Rothwell reported a bad merge between
next and Linus's tree. That's when I realized I had pushed the wrong
branch.
This is the broken branch. I already updated my for-next branch with
the correct commits and when Stephen syncs the linux-next tree, it
should be fixed.
-- Steve
>
> 1539
> --> 1540 while (true) {
> 1541 raw_spin_lock_irqsave(&cpu_buffer->reader_lock,
> flags);
> 1542
> 1543 if (buffer_cnt != cpu_buffer->cnt) {
> 1544 /* The list was updated, try again. */
> 1545
> raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
> 1546 goto again;
> 1547 }
> 1548
> 1549 tmp = rb_list_head(tmp->next);
> 1550 if (tmp == head)
> 1551 /* The iteration circled back, all is done.
> */
> 1552 goto out_locked;
> 1553
> 1554 if (!rb_check_links(cpu_buffer, tmp))
> 1555 goto out_locked;
> 1556
> 1557 raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock,
> flags);
> 1558 }
> 1559
> 1560 out_locked:
> 1561 raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
> 1562 }
>
> regards,
> dan carpenter
