From: Lukas Schauer Date: Fri, 1 Dec 2023 10:11:28 +0000 (+0100) Subject: pipe: wakeup wr_wait after setting max_usage X-Git-Tag: v6.6.17~506 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=68e51bdb1194f11d3452525b99c98aff6f837b24;p=platform%2Fkernel%2Flinux-rpi.git pipe: wakeup wr_wait after setting max_usage [ Upstream commit e95aada4cb93d42e25c30a0ef9eb2923d9711d4a ] 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 [1] Link: https://lore.kernel.org/r/20231201-orchideen-modewelt-e009de4562c6@brauner Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reviewed-by: David Howells Cc: Signed-off-by: Lukas Schauer [Christian Brauner : rewrite to account for watch queues] Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin --- diff --git a/fs/pipe.c b/fs/pipe.c index 603ab19..a234035 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -1305,6 +1305,11 @@ int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots) 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 */ @@ -1356,8 +1361,6 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned int arg) 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: