tree 2f5da76650d3d77b40923c6b632d23b8e15a4837
parent 5c8fe583cce542aa0b84adc939ce85293de36e5e
author Jens Axboe <axboe@kernel.dk> 1609264246 -0700
committer Jens Axboe <axboe@kernel.dk> 1609264836 -0700

io_uring: don't assume mm is constant across submits

If we COW the identity, we assume that ->mm never changes. But this
isn't true of multiple processes end up sharing the ring. Hence treat
id->mm like like any other process compontent when it comes to the
identity mapping. This is pretty trivial, just moving the existing grab
into io_grab_identity(), and including a check for the match.

Cc: stable@vger.kernel.org # 5.10
Fixes: 1e6fa5216a0e ("io_uring: COW io_identity on mismatch")
Reported-by: Christian Brauner <christian.brauner@ubuntu.com>:
Tested-by: Christian Brauner <christian.brauner@ubuntu.com>:
Signed-off-by: Jens Axboe <axboe@kernel.dk>