Re: io_uring failure on parisc with VIPT caches

Jens Axboe
2023-02-16T02:50:40Z

On 2/15/23 7:40 PM, John David Anglin wrote:
> On 2023-02-15 6:02 p.m., Jens Axboe wrote:
>> This is not related to Helge's patch, 6.1-stable is just still missing:
>>
>> commit fcc926bb857949dbfa51a7d95f3f5ebc657f198c
>> Author: Jens Axboe<axboe@kernel.dk>
>> Date:   Fri Jan 27 09:28:13 2023 -0700
>>
>>      io_uring: add a conditional reschedule to the IOPOLL cancelation loop
>>
>> and I'm guessing you're running without preempt.
> With 6.2.0-rc8+, I had a different crash running poll-race-mshot.t:
>
> Backtrace:
>
>
> Kernel Fault: Code=15 (Data TLB miss fault) at addr 0000000000000000
> CPU: 0 PID: 18265 Comm: poll-race-mshot Not tainted 6.2.0-rc8+ #1
> Hardware name: 9000/800/rp3440
>
>      YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
> PSW: 00010000001001001001000111110000 Not tainted
> r00-03  00000000102491f0 ffffffffffffffff 000000004020307c ffffffffffffffff
> r04-07  ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
> r08-11  ffffffffffffffff 000000000407ef28 000000000407f838 8400000000800000
> r12-15  0000000000000000 0000000040c424e0 0000000040c424e0 0000000040c424e0
> r16-19  000000000407fd68 0000000063f08648 0000000040c424e0 000000000a085000
> r20-23  00000000000d6b44 000000002faf0800 00000000000000ff 0000000000000002
> r24-27  000000000407fa30 000000000407fd68 0000000000000000 0000000040c1e4e0
> r28-31  400000000000de84 0000000000000000 0000000000000000 0000000000000002
> sr00-03  0000000004081000 0000000000000000 0000000000000000 0000000004081de0
> sr04-07  0000000004081000 0000000000000000 0000000000000000 00000000040815a8
>
> IASQ: 0000000004081000 0000000000000000 IAOQ: 0000000000000000 0000000004081590
>  IIR: 00000000    ISR: 0000000000000000  IOR: 0000000000000000
>  CPU:        0   CR30: 000000004daf5700 CR31: ffffffffffffefff
>  ORIG_R28: 0000000000000000
>  IAOQ[0]: 0x0
>  IAOQ[1]: linear_quiesce+0x0/0x18 [linear]
>  RP(r2): intr_check_sig+0x0/0x3c
> Backtrace:
>
> Kernel panic - not syncing: Kernel Fault

This means very little to me, is it a NULL pointer deref? And where's
the backtrace?

--
Jens Axboe