tree 7a713ecd9928357b1ae8fac0277079488c0edd9b
parent 573a3228ca3268441ce334251cb9fec0d69ca574
author David Howells <dhowells@redhat.com> 1647005018 +0000
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1647436562 +0100

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 <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>