Re: chacha20-s390 broken in 8.2.0 in TCG on s390x

[Richard Henderson]

On 12/22/23 01:51, Michael Tokarev wrote:
> When running current kernel on s390x in tcg mode *on s390x hw*, the following
> is generated when loading crypto selftest module (it gets loaded automatically):
>
> [   10.546690] alg: skcipher: chacha20-s390 encryption test failed (wrong result) on test 
> vector 1, cfg="in-place (one sglist)"
> [   10.546914] alg: self-tests for chacha20 using chacha20-s390 failed (rc=-22)
> [   10.546969] ------------[ cut here ]------------
> [   10.546998] alg: self-tests for chacha20 using chacha20-s390 failed (rc=-22)
> [   10.547182] WARNING: CPU: 1 PID: 109 at crypto/testmgr.c:5936 
> alg_test+0x55a/0x5b8
> [   10.547510] Modules linked in: net_failover chacha_s390(+) libchacha virtio_blk(+) 
> failover
> [   10.547854] CPU: 1 PID: 109 Comm: cryptomgr_test Not tainted 6.5.0-5-s390x #1  Debian 
> 6.5.13-1
> [   10.548002] Hardware name: QEMU 8561 QEMU (KVM/Linux)
> [   10.548101] Krnl PSW : 0704c00180000000 00000000005df8fe 
> (alg_test+0x55e/0x5b8)
> [   10.548207]            R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 
> RI:0 EA:3
> [   10.548291] Krnl GPRS: 0000000000000000 0000000001286408 00000000005df8fa 
> 0000000001286408
> [   10.548337]            000000000014bf14 00000000001c6ba8 0000000001838b3c 
> 0000000000000005
> [   10.548475]            00000000025a4880 00000000025a4800 ffffffffffffffea 
> 00000000ffffffea
> [   10.548521]            000000003e649200 00000000ffffffff 00000000005df8fa 
> 000003800016bcf8
> [   10.549504] Krnl Code: 00000000005df8ee: c020003b5828    larl    
> %r2,0000000000d4a93e
> [   10.549504]            00000000005df8f4: c0e5ffdb62d2    brasl    
> %r14,000000000014be98
> [   10.549504]           #00000000005df8fa: af000000        mc    0,0
> [   10.549504]           >00000000005df8fe: a7f4fee6        brc    
> 15,00000000005df6ca
> [   10.549504]            00000000005df902: b9040042        lgr    %r4,%r2
> [   10.549504]            00000000005df906: b9040039        lgr    %r3,%r9
> [   10.549504]            00000000005df90a: c020003b57df    larl    
> %r2,0000000000d4a8c8
> [   10.549504]            00000000005df910: 18bd        lr    %r11,%r13
> [   10.550004] Call Trace:
> [   10.550375]  [<00000000005df8fe>] alg_test+0x55e/0x5b8
> [   10.550467] ([<00000000005df8fa>] alg_test+0x55a/0x5b8)
> [   10.550489]  [<00000000005d9fbc>] cryptomgr_test+0x34/0x60
> [   10.550514]  [<000000000017d004>] kthread+0x124/0x130
> [   10.550539]  [<0000000000103124>] __ret_from_fork+0x3c/0x50
> [   10.550562]  [<0000000000b1dfca>] ret_from_fork+0xa/0x30
> [   10.550611] Last Breaking-Event-Address:
> [   10.550626]  [<000000000014bf20>] __warn_printk+0x88/0x110
> [   10.550723] ---[ end trace 0000000000000000 ]---
>
> git bisect points to this commit:
>
> commit ab84dc398b3b702b0c692538b947ef65dbbdf52f
> Author: Richard Henderson <richard.henderson@linaro.org>
> Date:   Wed Aug 23 23:04:24 2023 -0700
>
>      tcg/optimize: Optimize env memory operations
>
> So far, this seems to work on amd64 host, but fails on s390x host -
> where this has been observed so far.  Maybe it also fails in some
> other combinations too, I don't yet know.  Just finished bisecting
> it on s390x.

I haven't been able to build a reproducer for this.
Have you an image or kernel you can share?


r~