fs/aio: Check IOCB_AIO_RW before the struct aio_kiocb conversion
commit 961ebd120565cb60cebe21cb634fbc456022db4a upstream.
The first kiocb_set_cancel_fn() argument may point at a struct kiocb
that is not embedded inside struct aio_kiocb. With the current code,
depending on the compiler, the req->ki_ctx read happens either before
the IOCB_AIO_RW test or after that test. Move the req->ki_ctx read such
that it is guaranteed that the IOCB_AIO_RW test happens first.
Reported-by: Eric Biggers <ebiggers@kernel.org>
Cc: Benjamin LaHaise <ben@communityfibre.ca>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Avi Kivity <avi@scylladb.com>
Cc: Sandeep Dhavale <dhavale@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: stable@vger.kernel.org
Fixes: b820de741ae4 ("fs/aio: Restrict kiocb_set_cancel_fn() to I/O submitted via libaio")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240304235715.3790858-1-bvanassche@acm.org
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 10ca82aff58434e122c7c757cf0497c335f993f3)
[Vegard: fix conflicts due to missing commit
54843f875f7a9f802bbb0d9895c3266b4a0b2f37 ("aio: refactor read/write
iocb setup"); note however that this fixes commit
d9bf292a90ce3928db273d3cbba8b9a9fd588e9c ("fs/aio: Restrict
kiocb_set_cancel_fn() to I/O submitted via libaio") in 4.14, where we
noted that the code is a no-op due to missing io_uring.]
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
1 file changed