Re: io_uring failure on parisc with VIPT caches

[Jens Axboe <axboe@kernel.dk>]

On 2/15/23 1:27?PM, John David Anglin wrote:
> On 2023-02-15 2:16 p.m., Jens Axboe wrote:
>> In any case, with the silly syzbot mmap stuff fixed up, I'm not seeing
>> anything odd. A few tests will time out as they simply run too slowly
>> emulated for me, but apart from that, seems fine. This is running with
>> Helge's patch, though not sure if that is required running emulated.
> I'm seeing two problematic tests:
> 
> test buf-ring.t generates on console:
> TCP: request_sock_TCP: Possible SYN flooding on port 8495. Sending
> cookies.  Check SNMP counters.

Pretty sure that's from connect.t, not from buf-ring.t. But yes, this
happens on all platforms, haven't looked into it. The test works, but
would be nice to clean that up.

> System crashes running test buf-ring.t.

Huh, what's the crash?

> Running test buf-ring.t bad run 0/0 = -233

THis one, and the similar -223 ones, you need to try and dig into that.
It doesn't reproduce for me, and it very much seems like the test case
having a different view of what -ENOBUFS looks like and hence it fails
when the kernel passes down something that is -ENOBUFS internally, but
doesn't match the app -ENOBUFS value. Are you running a 64-bit kernel?
Would that cause any differences?

I don't see this on qemu with the 32-bit kernel, nor does it happen on
other platforms.

-- 
Jens Axboe