Patch "fs/aio: Make io_cancel() generate completions again" is based on the
assumption that calling kiocb->ki_cancel() does not complete R/W requests.
This is incorrect: the two drivers that call kiocb_set_cancel_fn() callers
set a cancellation function that calls usb_ep_dequeue(). According to its
documentation, usb_ep_dequeue() calls the completion routine with status
-ECONNRESET. Hence this revert.
Cc: Benjamin LaHaise <ben@xxxxxxxxxxxxxxxxx>
Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Avi Kivity <avi@xxxxxxxxxxxx>
Cc: Sandeep Dhavale <dhavale@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: syzbot+b91eb2ed18f599dd3c31@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 54cbc058d86b ("fs/aio: Make io_cancel() generate completions again")
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
fs/aio.c | 27 ++++++++++++++++-----------
1 file changed, 16 insertions(+), 11 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c
index 28223f511931..da18dbcfcb22 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -2165,11 +2165,14 @@ 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 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.
+ * 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.
*/
SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
struct io_event __user *, result)
@@ -2200,12 +2203,14 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
}
spin_unlock_irq(&ctx->ctx_lock);
- /*
- * The result argument is no longer used - the io_event is always
- * delivered via the ring buffer.
- */
- if (ret == 0 && kiocb->rw.ki_flags & IOCB_AIO_RW)
- aio_complete_rw(&kiocb->rw, -EINTR);
+ if (!ret) {
+ /*
+ * The result argument is no longer used - the io_event is
+ * always delivered via the ring buffer. -EINPROGRESS indicates
+ * cancellation is progress:
+ */
+ ret = -EINPROGRESS;
+ }
percpu_ref_put(&ctx->users);
