[PATCH v5.10 1/1] io_uring: Use original task for req identity in io_identity_cow()

[PATCH v5.10 1/1] io_uring: Use original task for req identity in io_identity_cow()

[Lee Jones]

This issue is conceptually identical to the one fixed in 29f077d07051
("io_uring: always use original task when preparing req identity"), so
rather than reinvent the wheel, I'm shamelessly quoting the commit
message from that patch - thanks Jens:

 "If the ring is setup with IORING_SETUP_IOPOLL and we have more than
  one task doing submissions on a ring, we can up in a situation where
  we assign the context from the current task rather than the request
  originator.

  Always use req->task rather than assume it's the same as current.

  No upstream patch exists for this issue, as only older kernels with
  the non-native workers have this problem."

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: io-uring@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Fixes: 5c3462cfd123b ("io_uring: store io_identity in io_uring_task")
Signed-off-by: Lee Jones <lee@kernel.org>
---
 fs/io_uring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 023c3eb34dcca..a952288b2ab8e 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1325,7 +1325,7 @@ static void io_req_clean_work(struct io_kiocb *req)
  */
 static bool io_identity_cow(struct io_kiocb *req)
 {
-	struct io_uring_task *tctx = current->io_uring;
+	struct io_uring_task *tctx = req->task->io_uring;
 	const struct cred *creds = NULL;
 	struct io_identity *id;
 
-- 
2.37.0.170.g444d1eabd0-goog

Re: [PATCH v5.10 1/1] io_uring: Use original task for req identity in io_identity_cow()

[Jens Axboe]

On 7/19/22 5:52 AM, Lee Jones wrote:
> This issue is conceptually identical to the one fixed in 29f077d07051
> ("io_uring: always use original task when preparing req identity"), so
> rather than reinvent the wheel, I'm shamelessly quoting the commit
> message from that patch - thanks Jens:
> 
>  "If the ring is setup with IORING_SETUP_IOPOLL and we have more than
>   one task doing submissions on a ring, we can up in a situation where
>   we assign the context from the current task rather than the request
>   originator.
> 
>   Always use req->task rather than assume it's the same as current.
> 
>   No upstream patch exists for this issue, as only older kernels with
>   the non-native workers have this problem."

Greg, can you pick this one up for 5.10-stable? Thanks!

-- 
Jens Axboe

Re: [PATCH v5.10 1/1] io_uring: Use original task for req identity in io_identity_cow()

[Greg KH]

On Wed, Jul 20, 2022 at 06:48:09AM -0600, Jens Axboe wrote:
> On 7/19/22 5:52 AM, Lee Jones wrote:
> > This issue is conceptually identical to the one fixed in 29f077d07051
> > ("io_uring: always use original task when preparing req identity"), so
> > rather than reinvent the wheel, I'm shamelessly quoting the commit
> > message from that patch - thanks Jens:
> > 
> >  "If the ring is setup with IORING_SETUP_IOPOLL and we have more than
> >   one task doing submissions on a ring, we can up in a situation where
> >   we assign the context from the current task rather than the request
> >   originator.
> > 
> >   Always use req->task rather than assume it's the same as current.
> > 
> >   No upstream patch exists for this issue, as only older kernels with
> >   the non-native workers have this problem."
> 
> Greg, can you pick this one up for 5.10-stable? Thanks!

Now queued up, thanks.

greg k-h