Re: RFC: remove set_fs for m68k

Michael Schmitz
2021-07-12T19:12:54Z

Hi Andreas,

On 12/07/21 10:20 pm, Andreas Schwab wrote:
> On Jul 11 2021, Michael Schmitz wrote:
>
>> Testing your series, I've got this in the console log:
>>
>> [16534.130000] *** FORMAT ERROR *** FORMAT=0
>> [16534.150000] Current process id is 1347
>> [16534.160000] BAD KERNEL TRAP: 00000000
>> [16534.180000] Modules linked in: atari_scsi ne 8390p
>> [16534.210000] PC: [<00002a8c>] resume_userspace+0x14/0x16
>> [16534.230000] SR: 2200 SP: d1b6e0e8 a2: 00000000
>> [16534.240000] d0: 0000001e d1: 00000003 d2: 00000578 d3: 00000000
>> [16534.270000] d4: ffffffff d5: 00000001 a0: 00000578 a1: 00000080
>> [16534.300000] Process savelog (pid: 1347, task=e3955528)
>> [16534.310000] Frame format=0
>> [16534.330000] Stack from 005e9fa4:
>> [16534.330000] 02108005 0d06b008 1eeeb649 007e0001 00aea040
>> 003ec318 005e9e68 000279a2
>> [16534.330000] 000b0000 00000000 00000000 030dfffb 0044fffa
>> 0e000000 fffa1a00 fffa1c00
>> [16534.330000] fffa1e00 fffb0e40 fffb0e80 00049e02 00000040
>> 0085a800 00000001
>> [16534.430000] Call Trace: [<000279a2>] warn_slowpath_fmt+0x0/0x62
>> [16534.460000] [<000b0000>] vm_map_ram+0x144/0x5ae
>> [16534.490000] [<00049e02>] __handle_irq_event_percpu+0x38/0xce
>> [16534.520000]
>> [16534.540000] Code: 9f38 9f38 9f38 9f38 9f38 9f38 9f38 9f38 <9f38> 9f38
>> 9f38 9f38 9f38 9f38 9f38 9f38 9f38 9f38 9f38 9f38 9f38 9f38 9f38 9f38
> That looks like something overwrote the kernel code. 0x9f38 isn't an
> insn that you would ever see in the kernel.

That confirms my guess - can we rely on the call trace in that case? And
how does overwriting kernel code at that address tee up with the kernel
still happily chugging along?

Cheers,

Michael

>
> Andreas.
>