Commit
c73be61cede5 ("pipe: Add general notification queue support") a
regression was introduced that would lock up resized pipes under certain
conditions. See the reproducer in [1].
The commit resizing the pipe ring size was moved to a different
function, doing that moved the wakeup for pipe->wr_wait before actually
raising pipe->max_usage. If a pipe was full before the resize occured it
would result in the wakeup never actually triggering pipe_write.
Set @max_usage and @nr_accounted before waking writers if this isn't a
watch queue.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=212295
Link: https://lore.kernel.org/r/20231201-orchideen-modewelt-e009de4562c6@brauner
Fixes:
c73be61cede5 ("pipe: Add general notification queue support")
Reviewed-by: David Howells <dhowells@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Lukas Schauer <lukas@schauer.dev>
[Christian Brauner <brauner@kernel.org>: rewrite to account for watch queues]
Signed-off-by: Christian Brauner <brauner@kernel.org>
pipe->tail = tail;
pipe->head = head;
+ if (!pipe_has_watch_queue(pipe)) {
+ pipe->max_usage = nr_slots;
+ pipe->nr_accounted = nr_slots;
+ }
+
spin_unlock_irq(&pipe->rd_wait.lock);
/* This might have made more room for writers */
if (ret < 0)
goto out_revert_acct;
- pipe->max_usage = nr_slots;
- pipe->nr_accounted = nr_slots;
return pipe->max_usage * PAGE_SIZE;
out_revert_acct: