From: David Howells dhowells@redhat.com
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 jannh@google.com Signed-off-by: David Howells dhowells@redhat.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/pipe.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/fs/pipe.c +++ b/fs/pipe.c @@ -830,10 +830,8 @@ void free_pipe_info(struct pipe_inode_in 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_in 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);