Message-ID: <e48b72d4-558a-ed7c-43cd-0cb70091be11@intel.com>
Date:   Thu, 16 Dec 2021 20:21:15 +0800
From:   Yin Fengwei <fengwei.yin@...el.com>
To:     Carel Si <beibei.si@...el.com>, Borislav Petkov <bp@...e.de>
CC:     Joerg Roedel <jroedel@...e.de>,
        LKML <linux-kernel@...r.kernel.org>, <x86@...nel.org>,
        <lkp@...ts.01.org>, <lkp@...el.com>
Subject: Re: [LKP] Re: [x86/mm/64] f154f29085:
 BUG:kernel_reboot-without-warning_in_boot_stage

Hi Boris,

On 12/16/2021 7:58 PM, Carel Si wrote:
> Hi Boris,
> 
> On Thu, Dec 16, 2021 at 11:06:59AM +0100, Borislav Petkov wrote:
>> On Thu, Dec 16, 2021 at 03:04:16PM +0800, Yin Fengwei wrote:
>>> The testing was with Qemu.
>>
>> This is hardly what I asked for.
>>
>>> And we found that the hang is related with clang-14.
>>
>> I saw that already.
>>
>>> The original report showed the kernel is built with clang-14:
>>>         # build kernel
>>> 	cd linux
>>> 	cp config-5.16.0-rc3-00003-gf154f290855b .config
>>> 	make HOSTCC=clang-14 CC=clang-14 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage modules
>>> 	make HOSTCC=clang-14 CC=clang-14 ARCH=x86_64 INSTALL_MOD_PATH=<mod-install-dir> modules_install
>>
>> I saw that too.
>>
>>> Looks like KASAN related stub generated by clang-14 (KASAN_SHADOW_OFFSET and asan_report).
>>> This function is early function called before kasan_init.
>>>
>>> Looks like we need to disable KASAN_SANITIZE for arch/x86/kernel/cpu/common.c. So clang-14 will
>>> be happy with this kind of early TLB flush? Thanks.
>>
>> Ok, I don't understand: I asked for how exactly to reproduce and whether
>> you can send me your vmlinux you built with your clang-14. What I get is
>> some possible explanation about what might be happening.
>>
>> So what do you expect me to do? Say, "oh, sure, you're right, send me a
>> patch" without even being able to see for myself what the root cause is?
>>
>> What if it is not the kernel's fault but clang-14 is miscompiling crap
>> as in so many other cases?
>>
>> I built clang-14 and built with your .config and it works here fine. So
>> why does yours fail?
>>
>> Or what's the point of all this?

I had concern that our report is an invalid report because you can't reproduce
it in your side. If that's the case, it could waste more your time. That's why
I did check and shared what I got. I am very sorry if I did it wrong.


If you don't want to use lkp tool to reproduce the issue, following command
could be used as well:

Use Qemu command so only kernel image need be downloaded:
qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G -s -S -kernel vmlinuz-5.16.0-rc3-00003-gf154f290855b -nographic -append "console=ttyS0 earlyprintk=ttyS0,115200"
to reproduce it.



Regards
Yin, Fengwei



>>
>> I mean, if you cannot send me what I ask for, you can say so. Then I can
>> ignore this whole report altogether and waste my time somewhere else.
> 
> We have uploaded vmlinuz, modules.cgz, config as well as other related file to:
> https://download.01.org/0day-ci/lkp-qemu/pkg/linux/x86_64-randconfig-a013-20211207/clang-14/f154f290855b070cc94dd44ad253c0ef8a9337bb/
> 
> Machine types can refer to:
> https://zerobin.net/?e107cf7b56495d80#MQLh14wUT9Osv1tWCwiQx/okkAN48Nq+drVPE0PiNPw=
> 
> If there's any other msg needed, pls feel free to propose, thanks.
> 
> Below are our full steps to reproduce the issue:
> 
> # download lkp-tests
> $ git clone https://github.com/intel/lkp-tests.git
> 
> $ cd lkp-tests/
> 
> # download vmlinuz
> $ wget https://download.01.org/0day-ci/lkp-qemu/pkg/linux/x86_64-randconfig-a013-20211207/clang-14/f154f290855b070cc94dd44ad253c0ef8a9337bb/vmlinuz-5.16.0-rc3-00003-gf154f290855b
> 
> # dowmload modules.cgz
> $ wget https://download.01.org/0day-ci/lkp-qemu/pkg/linux/x86_64-randconfig-a013-20211207/clang-14/f154f290855b070cc94dd44ad253c0ef8a9337bb/modules.cgz
> 
> # download job-script which is attached
> 
> # run lkp qemu
> lkp-tests$ sudo bin/lkp qemu -k vmlinuz-5.16.0-rc3-00003-gf154f290855b -m modules.cgz job-script
> 
> ~/lkp-tests/pkg/lkp-src ~/lkp-tests
> x86_64
> ==> Making package: lkp-src 0-1 (Thu 16 Dec 2021 07:26:22 PM CST)
> ==> Checking runtime dependencies...
> ==> Checking buildtime dependencies...
> ==> WARNING: Using existing $srcdir/ tree
> ==> Removing existing $pkgdir/ directory...
> ==> Starting build()...
> make: Entering directory '/home/carel/lkp-tests/bin/event'
> klcc  -D_FORTIFY_SOURCE=2  -c -o wakeup.o wakeup.c
> klcc  -Wl,-O1,--sort-common,--as-needed,-z,relro -static -o wakeup wakeup.o
> rm -f wakeup.o
> strip wakeup
> make: Leaving directory '/home/carel/lkp-tests/bin/event'
> ==> Entering fakeroot environment...
> x86_64
> ==> Starting package()...
> ==> Creating package "lkp-src"...
> 103987 blocks
> renamed '/home/carel/.lkp/cache/lkp-x86_64.cgz.tmp' -> '/home/carel/.lkp/cache/lkp-x86_64.cgz'
> ==> Leaving fakeroot environment.
> ==> Finished making: lkp-src 0-1 (Thu 16 Dec 2021 07:26:24 PM CST)
> ~/lkp-tests
> 12 blocks
> result_root: /home/carel/.lkp//result/boot/1/vm-snb/debian-10.4-x86_64-20200603.cgz/x86_64-randconfig-a013-20211207/clang-14/f154f290855b070cc94dd44ad253c0ef8a9337bb/0
> downloading initrds ...
> use local modules: /home/carel/.lkp/cache/modules.cgz
> /usr/bin/wget -q --timeout=1800 --tries=1 --local-encoding=UTF-8 http://0day.sh.intel.com:80/~lkp/osimage/debian/debian-10.4-x86_64-20200603.cgz -N -P /home/carel/.lkp/cache/osimage/debian
> 440459 blocks
> /usr/bin/wget -q --timeout=1800 --tries=1 --local-encoding=UTF-8 http://0day.sh.intel.com:80/~lkp/osimage/deps/debian-10.4-x86_64-20200603.cgz/run-ipconfig_20200608.cgz -N -P /home/carel/.lkp/cache/osimage/deps/debian-10.4-x86_64-20200603.cgz
> 1773 blocks
> /usr/bin/wget -q --timeout=1800 --tries=1 --local-encoding=UTF-8 http://0day.sh.intel.com:80/~lkp/osimage/deps/debian-10.4-x86_64-20200603.cgz/lkp_20210707.cgz -N -P /home/carel/.lkp/cache/osimage/deps/debian-10.4-x86_64-20200603.cgz
> 2321 blocks
> /usr/bin/wget -q --timeout=1800 --tries=1 --local-encoding=UTF-8 http://0day.sh.intel.com:80/~lkp/osimage/deps/debian-10.4-x86_64-20200603.cgz/rsync-rootfs_20200608.cgz -N -P /home/carel/.lkp/cache/osimage/deps/debian-10.4-x86_64-20200603.cgz
> 6856 blocks
> exec command: qemu-system-x86_64 -enable-kvm -fsdev local,id=test_dev,path=/home/carel/.lkp//result/boot/1/vm-snb/debian-10.4-x86_64-20200603.cgz/x86_64-randconfig-a013-20211207/clang-14/f154f290855b070cc94dd44ad253c0ef8a9337bb/0,security_model=none -device virtio-9p-pci,fsdev=test_dev,mount_tag=9p/virtfs_mount -kernel vmlinuz-5.16.0-rc3-00003-gf154f290855b -append root=/dev/ram0 user=lkp job=/lkp/jobs/scheduled/vm-snb-192/boot-1-debian-10.4-x86_64-20200603.cgz-f154f290855b070cc94dd44ad253c0ef8a9337bb-20211208-23538-lnvkeg-5.yaml ARCH=x86_64 kconfig=x86_64-randconfig-a013-20211207 branch=tip/x86/mm commit=f154f290855b070cc94dd44ad253c0ef8a9337bb BOOT_IMAGE=/pkg/linux/x86_64-randconfig-a013-20211207/clang-14/f154f290855b070cc94dd44ad253c0ef8a9337bb/vmlinuz-5.16.0-rc3-00003-gf154f290855b vmalloc=128M initramfs_async=0 page_owner=on max_uptime=600 RESULT_ROOT=/result/boot/1/vm-snb/debian-10.4-x86_64-20200603.cgz/x86_64-randconfig-a013-20211207/clang-14/f154f290855b070cc94dd44ad253c0ef8a9337bb/3 LKP_LOCAL_RUN=1 selinux=0 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 net.ifnames=0 printk.devkmsg=on panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 drbd.minor_count=8 systemd.log_level=err ignore_loglevel console=tty0 earlyprintk=ttyS0,115200 console=ttyS0,115200 vga=normal rw  ip=dhcp result_service=9p/virtfs_mount -initrd /home/carel/.lkp/cache/final_initrd -smp 2 -m 3144M -no-reboot -watchdog i6300esb -rtc base=localtime -device e1000,netdev=net0 -netdev user,id=net0 -display none -monitor null -serial stdio
> early console in setup code
> early console in extract_kernel
> input_data: 0x0000000006ffc2e0
> input_len: 0x000000000260cb2b
> output: 0x0000000001000000
> output_len: 0x00000000079e7da4
> kernel_total_size: 0x0000000008a2c000
> needed_size: 0x0000000008c00000
> trampoline_32bit: 0x000000000009d000
> Physical KASLR using RDTSC...
> Virtual KASLR using RDTSC...
> 
> Decompressing Linux... Parsing ELF... Performing relocations... done.
> Booting the kernel.
> 
>>
>> -- 
>> Regards/Gruss,
>>     Boris.
>>
>> SUSE Software Solutions Germany GmbH, GF: Ivo Totev, HRB 36809, AG Nürnberg

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