From ef04688871f3386b6d40ade8f5c664290420f819 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 27 Jul 2021 10:50:31 -0600 Subject: [PATCH] io_uring: don't block level reissue off completion path Some setups, like SCSI, can throw spurious -EAGAIN off the softirq completion path. Normally we expect this to happen inline as part of submission, but apparently SCSI has a weird corner case where it can happen as part of normal completions. This should be solved by having the -EAGAIN bubble back up the stack as part of submission, but previous attempts at this failed and we're not just quite there yet. Instead we currently use REQ_F_REISSUE to handle this case. For now, catch it in io_rw_should_reissue() and prevent a reissue from a bogus path. Cc: stable@vger.kernel.org Reported-by: Fabian Ebner Tested-by: Fabian Ebner Signed-off-by: Jens Axboe --- fs/io_uring.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 6ba101cd4661..83f67d33bf67 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2447,6 +2447,12 @@ static bool io_rw_should_reissue(struct io_kiocb *req) */ if (percpu_ref_is_dying(&ctx->refs)) return false; + /* + * Play it safe and assume not safe to re-import and reissue if we're + * not in the original thread group (or in task context). + */ + if (!same_thread_group(req->task, current) || !in_task()) + return false; return true; } #else -- GitLab