fs/aio: Check IOCB_AIO_RW before the struct aio_kiocb conversion

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 <[email protected]>
Cc: Benjamin LaHaise <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Avi Kivity <[email protected]>
Cc: Sandeep Dhavale <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: [email protected]
Fixes: b820de741ae4 ("fs/aio: Restrict kiocb_set_cancel_fn() to I/O submitted via libaio")
Signed-off-by: Bart Van Assche <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Jens Axboe <[email protected]>
Reviewed-by: Eric Biggers <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

0 files changed, 0 insertions, 0 deletions