linux-stable/io_uring
Jens Axboe 36fc7317cd io_uring/poll: don't reissue in case of poll race on multishot request
commit 8caa03f10b upstream.

A previous commit fixed a poll race that can occur, but it's only
applicable for multishot requests. For a multishot request, we can safely
ignore a spurious wakeup, as we never leave the waitqueue to begin with.

A blunt reissue of a multishot armed request can cause us to leak a
buffer, if they are ring provided. While this seems like a bug in itself,
it's not really defined behavior to reissue a multishot request directly.
It's less efficient to do so as well, and not required to rearm anything
like it is for singleshot poll requests.

Cc: stable@vger.kernel.org
Fixes: 6e5aedb932 ("io_uring/poll: attempt request issue after racy poll wakeup")
Reported-and-tested-by: Olivier Langlois <olivier@trillion01.com>
Link: https://github.com/axboe/liburing/issues/778
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:37 +01:00
..
advise.c
advise.h
alloc_cache.h
cancel.c
cancel.h
epoll.c
epoll.h
fdinfo.c
fdinfo.h
filetable.c
filetable.h
fs.c
fs.h
io-wq.c
io-wq.h
io_uring.c
io_uring.h
kbuf.c
kbuf.h
Makefile
msg_ring.c
msg_ring.h
net.c
net.h
nop.c
nop.h
notif.c
notif.h
opdef.c
opdef.h
openclose.c
openclose.h
poll.c
poll.h
refs.h
rsrc.c
rsrc.h
rw.c
rw.h
slist.h
splice.c
splice.h
sqpoll.c
sqpoll.h
statx.c
statx.h
sync.c
sync.h
tctx.c
tctx.h
timeout.c
timeout.h
uring_cmd.c
uring_cmd.h
xattr.c
xattr.h