Unverified Commit 54cbc058 authored by Bart Van Assche's avatar Bart Van Assche Committed by Christian Brauner
Browse files

fs/aio: Make io_cancel() generate completions again 

The following patch accidentally removed the code for delivering
completions for cancelled reads and writes to user space: "[PATCH 04/33]
aio: remove retry-based AIO"
(https://lore.kernel.org/all/1363883754-27966-5-git-send-email-koverstreet@google.com/

)
>From that patch:

-	if (kiocbIsCancelled(iocb)) {
-		ret = -EINTR;
-		aio_complete(iocb, ret, 0);
-		/* must not access the iocb after this */
-		goto out;
-	}

This leads to a leak in user space of a struct iocb. Hence this patch
that restores the code that reports to user space that a read or write
has been cancelled successfully.

Fixes: 41003a7b ("aio: remove retry-based AIO")
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
Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240215204739.2677806-3-bvanassche@acm.org


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 5f7a0764

fs/aio.c

+11 −16
Original line number Diff line number Diff line
@@ -2165,14 +2165,11 @@ COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id, 
#endif



/* sys_io_cancel:

 *	Attempts to cancel an iocb previously passed to io_submit.  If

 *	the operation is successfully cancelled, the resulting event is

 *	copied into the memory pointed to by result without being placed

 *	into the completion queue and 0 is returned.  May fail with

 *	-EFAULT if any of the data structures pointed to are invalid.

 *	May fail with -EINVAL if aio_context specified by ctx_id is

 *	invalid.  May fail with -EAGAIN if the iocb specified was not

 *	cancelled.  Will fail with -ENOSYS if not implemented.

 *	Attempts to cancel an iocb previously passed to io_submit(). If the

 *	operation is successfully cancelled 0 is returned. May fail with

 *	-EFAULT if any of the data structures pointed to are invalid. May

 *	fail with -EINVAL if aio_context specified by ctx_id is invalid. Will

 *	fail with -ENOSYS if not implemented.

 */

SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,

		struct io_event __user *, result)
@@ -2203,14 +2200,12 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, 
	}

	spin_unlock_irq(&ctx->ctx_lock);



	if (!ret) {

	/*

		 * The result argument is no longer used - the io_event is

		 * always delivered via the ring buffer. -EINPROGRESS indicates

		 * cancellation is progress:

	 * The result argument is no longer used - the io_event is always

	 * delivered via the ring buffer.

	 */

		ret = -EINPROGRESS;

	}

	if (ret == 0 && kiocb->rw.ki_flags & IOCB_AIO_RW)

		aio_complete_rw(&kiocb->rw, -EINTR);



	percpu_ref_put(&ctx->users);