On 7/28/21 3:26 AM, Fabian Ebner wrote: > Am 27.07.21 um 18:58 schrieb Jens Axboe: >> 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@xxxxxxxxxxxxxxx >> Reported-by: Fabian Ebner <f.ebner@xxxxxxxxxxx> >> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> >> --- >> 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 >> > > Hi, > > thank you for the fix! This does indeed prevent the panic (with 5.11.22) > and hang (with 5.13.3) with my problematic workload. Perfect, thanks for re-testing! Can I add your Tested-by to the patch? -- Jens Axboe
