Debian SID kernel doesn't boot on PowerBook 3400c

[Stan Johnson]

Hi Christophe,

On 7/31/21 9:58 AM, Christophe Leroy wrote:
> Stan Johnson <userm57 at yahoo.com> a écrit :
> 
>> Hello,
>>
>> The current Debian SID kernel will not boot on a PowerBook 3400c running
>> the latest version of Debian SID. If booted using the BootX extension,
>> the kernel hangs immediately:
>>
>> "Welcome to Linux, kernel 5.10.0-8-powerpc"
>>
>> If booted from Mac OS, the Mac OS screen hangs.
>>
>> Booting also hangs if the "No video driver" option is selected in BootX,
>> "No video driver" causes "video=ofonly" to be passed to the kernel.
>>
>> This is the current command line that I'm using in BootX:
>> root=/dev/sda13 video=chips65550:vmode:14,cmode:16
>>
>> Kernel v5.9 works as expected.
>>
>> The config file I'm using is attached.
>>
>> Here are the results of a git bisect, marking v5.9 as "good" and the
>> most current kernel as "bad":
>>
>> $ cd linux
>> $ git remote update
>> $ git bisect reset
>> $ git bisect start
>> $ git bisect bad
>> $ git bisect good v5.9
>>
>> Note: "bad" -> hangs at boot; "good" -> boots to login prompt
>>
>>  1) 5.11.0-rc5-pmac-00034-g684da7628d9 (bad)
>>  2) 5.10.0-rc3-pmac-00383-gbb9dd3ce617 (good)
>>  3) 5.10.0-pmac-06637-g2911ed9f47b (good)
>>     Note: I had to disable SMP to build this kernel.
>>  4) 5.10.0-pmac-10584-g9805529ec54 (good)
>>     Note: I had to disable SMP to build this kernel.
>>  5) 5.10.0-pmac-12577-g8552d28e140 (bad)
>>  6) 5.10.0-pmac-11576-g8a5be36b930 (bad)
>>  7) 5.10.0-pmac-11044-gbe695ee29e8 (good)
>>     Note: I had to disable SMP to build this kernel.
>>  8) 5.10.0-rc2-pmac-00288-g59d512e4374 (bad)
>>  9) 5.10.0-rc2-pmac-00155-gc3d35ddd1ec (good)
>> 10) 5.10.0-rc2-pmac-00221-g7049b288ea8 (good)
>> 11) 5.10.0-rc2-pmac-00254-g4b74a35fc7e (bad)
>> 12) 5.10.0-rc2-pmac-00237-ged22bb8d39f (good)
>> 13) 5.10.0-rc2-pmac-00245-g87b57ea7e10 (good)
>> 14) 5.10.0-rc2-pmac-00249-gf10881a46f8 (bad)
>> 15) 5.10.0-rc2-pmac-00247-gf8a4b277c3c (good)
>> 16) 5.10.0-rc2-pmac-00248-gdb972a3787d (bad)
>>
>> db972a3787d12b1ce9ba7a31ec376d8a79e04c47 is the first bad commit
> 
> Not sure this is really the root of the problem.
> 
> Can you try again without CONFIG_VMAP_STACK ?
> 
> Thanks
> Christophe
> ...


With CONFIG_VMAP_STACK=y, 5.11.0-rc5-pmac-00034-g684da7628d9 hangs at
boot on the PB 3400c.

Without CONFIG_VMAP_STACK, 5.11.0-rc5-pmac-00034-g684da7628d9 boots as
expected.

I didn't re-build the Debian SID kernel, though I confirmed that the
Debian config file for 5.10.0-8-powerpc includes CONFIG_VMAP_STACK=y.
It's not clear whether removing CONFIG_VMAP_STACK would be appropriate
for other powerpc systems.

Please let me know why removing CONFIG_VMAP_STACK fixed the problem on
the PB 3400c. Should CONFIG_HAVE_ARCH_VMAP_STACK also be removed?

thanks

-Stan Johnson