From 8275b6699c6dda4d4cec748bc2e879cac532d193 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 11 Mar 2022 13:23:38 +0000 Subject: [PATCH] watch_queue, pipe: Free watchqueue state after clearing pipe ring commit db8facfc9fafacefe8a835416a6b77c838088f8b upstream. In free_pipe_info(), free the watchqueue state after clearing the pipe ring as each pipe ring descriptor has a release function, and in the case of a notification message, this is watch_queue_pipe_buf_release() which tries to mark the allocation bitmap that was previously released. Fix this by moving the put of the pipe's ref on the watch queue to after the ring has been cleared. We still need to call watch_queue_clear() before doing that to make sure that the pipe is disconnected from any notification sources first. Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reported-by: Jann Horn Signed-off-by: David Howells Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/pipe.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/pipe.c b/fs/pipe.c index 6d4342bad9f15..8b0f6979fb49c 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -830,10 +830,8 @@ void free_pipe_info(struct pipe_inode_info *pipe) int i; #ifdef CONFIG_WATCH_QUEUE - if (pipe->watch_queue) { + if (pipe->watch_queue) watch_queue_clear(pipe->watch_queue); - put_watch_queue(pipe->watch_queue); - } #endif (void) account_pipe_buffers(pipe->user, pipe->nr_accounted, 0); @@ -843,6 +841,10 @@ void free_pipe_info(struct pipe_inode_info *pipe) if (buf->ops) pipe_buf_release(pipe, buf); } +#ifdef CONFIG_WATCH_QUEUE + if (pipe->watch_queue) + put_watch_queue(pipe->watch_queue); +#endif if (pipe->tmp_page) __free_page(pipe->tmp_page); kfree(pipe->bufs); -- 2.30.2