Re: [PATCH v2 2/7] MIPS: csrc-r4k: Apply verification clocksource flags

["Jiaxun Yang" <jiaxun.yang@flygoat.com>]

在2024年8月6日八月 下午12:09，Guenter Roeck写道：
> Hi,
>
> On Wed, Jun 12, 2024 at 09:54:29AM +0100, Jiaxun Yang wrote:
>> CP0 counter suffers from various problems like SMP sync,
>> behaviour on wait.
>> 
>> Set CLOCK_SOURCE_MUST_VERIFY and CLOCK_SOURCE_VERIFY_PERCPU,
>> as what x86 did to TSC, to let kernel test it before use.
>> 
>> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>

Hi Guenter,

Thanks for the report, it makes no sense to me though....

I can't reproduce it with QEMU git master, do you mind specifying your QEMU
version for me? Also is it possible to have a copy of dmesg when failure happens.

If I'm unable to resolve it in a couple of days, I'll send a patch to revert this change.

Thanks

>
> With this patch in the mainline kernel, about one in five qemu
> boot attempts with e1000 Ethernet controller fail to activate
> the network interface (specifically, the dhcp client is unable to
> get an IP address for the interface). Bisect log is attached below.
>
> For reference, here is an example command line.
>
> qemu-system-mips64 -kernel vmlinux -M malta -cpu 5KEc \
> 	-initrd rootfs-n32.cpio \
> 	-device e1000,netdev=net0 -netdev user,id=net0 \
> 	-vga cirrus -no-reboot -m 256 \
> 	--append "rdinit=/sbin/init mem=256M console=ttyS0 console=tty " \
> 	-nographic
>
> Reverting this patch fixes the probem.
>
> Thanks,
> Guenter
>
> ---
> # bad: [de9c2c66ad8e787abec7c9d7eff4f8c3cdd28aed] Linux 6.11-rc2
> # good: [0c3836482481200ead7b416ca80c68a29cfdaabd] Linux 6.10
> git bisect start 'HEAD' 'v6.10'
> # good: [280e36f0d5b997173d014c07484c03a7f7750668] nsfs: use cleanup 
> guard
> git bisect good 280e36f0d5b997173d014c07484c03a7f7750668
> # good: [a4f9285520584977127946a22eab2adfbc87d1bf] Merge tag 
> 'clk-for-linus' of 
> git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux
> git bisect good a4f9285520584977127946a22eab2adfbc87d1bf
> # bad: [8e313211f7d46d42b6aa7601b972fe89dcc4a076] Merge tag 
> 'pinctrl-v6.11-1' of 
> git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl
> git bisect bad 8e313211f7d46d42b6aa7601b972fe89dcc4a076
> # good: [acc5965b9ff8a1889f5b51466562896d59c6e1b9] Merge tag 
> 'char-misc-6.11-rc1' of 
> git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
> git bisect good acc5965b9ff8a1889f5b51466562896d59c6e1b9
> # bad: [d2be38b9a5514dbc7dc0c96a2a7f619fcddce00d] Merge tag 'mips_6.11' 
> of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux
> git bisect bad d2be38b9a5514dbc7dc0c96a2a7f619fcddce00d
> # good: [45659274e60864f9acabba844468e405362bdc8c] Merge branch 
> 'pci/misc'
> git bisect good 45659274e60864f9acabba844468e405362bdc8c
> # good: [8e5c0abfa02d85b9cd2419567ad2d73ed8fe4b74] Merge tag 
> 'input-for-v6.11-rc0' of 
> git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
> git bisect good 8e5c0abfa02d85b9cd2419567ad2d73ed8fe4b74
> # good: [3c3ff7be9729959699eb6cbc7fd7303566d74069] Merge tag 
> 'powerpc-6.11-1' of 
> git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
> git bisect good 3c3ff7be9729959699eb6cbc7fd7303566d74069
> # good: [3de96d810ffd712b7ad2bd764c1390fac2436551] dt-bindings: mips: 
> brcm: Document brcm,bmips-cbr-reg property
> git bisect good 3de96d810ffd712b7ad2bd764c1390fac2436551
> # bad: [9c7a86c935074525f24cc20e78a7d5150e4600e3] MIPS: lantiq: improve 
> USB initialization
> git bisect bad 9c7a86c935074525f24cc20e78a7d5150e4600e3
> # bad: [580724fce27f2b71b3e4d58bbe6d83b671929b33] MIPS: sync-r4k: 
> Rework based on x86 tsc_sync
> git bisect bad 580724fce27f2b71b3e4d58bbe6d83b671929b33
> # good: [c171186c177970d3ec22dd814f2693f1f7fc1e7d] MIPS: csrc-r4k: 
> Refine rating computation
> git bisect good c171186c177970d3ec22dd814f2693f1f7fc1e7d
> # bad: [426fa8e4fe7bb914b5977cbce453a9926bf5b2e6] MIPS: csrc-r4k: 
> Select HAVE_UNSTABLE_SCHED_CLOCK if SMP && 64BIT
> git bisect bad 426fa8e4fe7bb914b5977cbce453a9926bf5b2e6
> # bad: [7190401fc56fb5f02ee3d04476778ab000bbaf32] MIPS: csrc-r4k: Apply 
> verification clocksource flags
> git bisect bad 7190401fc56fb5f02ee3d04476778ab000bbaf32
> # first bad commit: [7190401fc56fb5f02ee3d04476778ab000bbaf32] MIPS: 
> csrc-r4k: Apply verification clocksource flags

-- 
- Jiaxun