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Subject: Re: [LKP] Re: 28307d938f ("percpu: make pcpu_alloc() aware of current
 gfp .."): BUG: kernel reboot-without-warning in boot stage
To:     Filipe Manana <fdmanana@suse.com>,
        kernel test robot <lkp@intel.com>
Cc:     LKP <lkp@lists.01.org>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
        "Linus, Torvalds," <torvalds@linux-foundation.org>
References: <5ed0b6ea.QaEVKYBGHpcVDpW8%lkp@intel.com>
 <21fb7dbf-1fd2-cfcb-860e-c342ae0c310e@suse.com>
From:   Li Zhijian <zhijianx.li@intel.com>
Message-ID: <a1e41149-a3b3-4a19-7001-9b47d8b66555@intel.com>
Date:   Tue, 2 Jun 2020 12:37:24 +0800
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Hi Filipe,

LKP checked blow dmesg as the indicator in this problem

>> [    0.144174] RAMDISK: [mem 0x7fa2e000-0x7fffffff]
>> [    0.144559] ACPI: Early table checksum verification disabled
>> [    0.144985] ACPI: RSDP 0x00000000000F5850 000014 (v00 BOCHS )
>> [    0.145424] ACPI: RSDT 0x00000000BFFE15C9 000030 (v01 BOCHS  BXPCRSDT 00000001 BXPC 00000001)
>> [    0.146051] ACPI: FACP 0x00000000BFFE149D 000074 (v01 BOCHS  BXPCFACP 00000001 BXPC 00000001)
>> BUG: kernel reboot-without-warning in boot stage
>>

And i have reproduced it with script in attachment. this issue is gone 
when i reverted this commit 28307d938f

Please note that
- i reproduced it with kernel compiled by gcc-5
- i failed to reproduce it in kernel compiled by gcc-7 so far

:~/1787$ ./reproduce.sh obj/arch/x86/boot/bzImage
qemu-system-x86_64 -enable-kvm -cpu Haswell,+smep,+smap -kernel 
obj/arch/x86/boot/bzImage -m 8192 -smp 2 -device e1000,netdev=net0 
-netdev user,id=net0,hostfwd=tcp::32032-:22 -boot order=nc -no-reboot 
-watchdog i6300esb -watchdog-action debug -rtc base=localtime -serial 
stdio -display none -monitor null -append root=/dev/ram0 
hung_task_panic=1 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 rcuperf.shutdown=0 watchdog_thresh=60
early console in setup code
Wrong EFI loader signature.
early console in extract_kernel
input_data: 0x0000000006f752d8
input_len: 0x000000000130dd3c
output: 0x0000000001000000
output_len: 0x0000000007200a48
kernel_total_size: 0x0000000006826000
needed_size: 0x0000000007400000
trampoline_32bit: 0x000000000009d000

Decompressing Linux... Parsing ELF... done.
Booting the kernel.
[    0.000000] Linux version 5.7.0-rc4-00168-g28307d938fb2 
(lizhijian@shao2-debian) (gcc version 5.5.0 20171010 (Debian 5.5.0-12), 
GNU ld (GNU Binutils for Debian) 2.34) #2 SMP PREEMPT Tue Jun 2 11:23:59 
CST 2020
[    0.000000] Command line: root=/dev/ram0 hung_task_panic=1 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 
rcuperf.shutdown=0 watchdog_thresh=60
[    0.000000] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating 
point registers'
[    0.000000] x86/fpu: Supporting XSAVE feature 0x002: 'SSE registers'
[    0.000000] x86/fpu: Supporting XSAVE feature 0x004: 'AVX registers'
[    0.000000] x86/fpu: xstate_offset[2]:  576, xstate_sizes[2]: 256
[    0.000000] x86/fpu: Enabled xstate features 0x7, context size is 832 
bytes, using 'standard' format.
[    0.000000] BIOS-provided physical RAM map:
[    0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
[    0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] 
reserved
[    0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] 
reserved
[    0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000bffdffff] usable
[    0.000000] BIOS-e820: [mem 0x00000000bffe0000-0x00000000bfffffff] 
reserved
[    0.000000] BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] 
reserved
[    0.000000] BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] 
reserved
[    0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000023fffffff] usable
[    0.000000] printk: debug: ignoring loglevel setting.
[    0.000000] printk: bootconsole [earlyser0] enabled
[    0.000000] NX (Execute Disable) protection: active
[    0.000000] SMBIOS 2.8 present.
[    0.000000] DMI: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 
1.12.0-1 04/01/2014
[    0.000000] Hypervisor detected: KVM
[    0.000000] kvm-clock: Using msrs 4b564d01 and 4b564d00
[    0.000002] kvm-clock: cpu 0, msr 7601001, primary cpu clock
[    0.000002] kvm-clock: using sched offset of 2661499940 cycles
[    0.000603] clocksource: kvm-clock: mask: 0xffffffffffffffff 
max_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns
[    0.002261] tsc: Detected 3407.998 MHz processor
[    0.005351] e820: update [mem 0x00000000-0x00000fff] usable ==> reserved
[    0.005986] e820: remove [mem 0x000a0000-0x000fffff] usable
[    0.006535] last_pfn = 0x240000 max_arch_pfn = 0x400000000
[    0.007091] MTRR default type: write-back
[    0.007477] MTRR fixed ranges enabled:
[    0.007845]   00000-9FFFF write-back
[    0.008191]   A0000-BFFFF uncachable
[    0.008536]   C0000-FFFFF write-protect
[    0.008906] MTRR variable ranges enabled:
[    0.009293]   0 base 00C0000000 mask FFC0000000 uncachable
[    0.009818]   1 disabled
[    0.010064]   2 disabled
[    0.010314]   3 disabled
[    0.010561]   4 disabled
[    0.010822]   5 disabled
[    0.011072]   6 disabled
[    0.011325]   7 disabled
[    0.011602] x86/PAT: Configuration [0-7]: WB  WC  UC- UC  WB  WP UC- WT
[    0.012313] last_pfn = 0xbffe0 max_arch_pfn = 0x400000000
[    0.013294] check: Scanning 1 areas for low memory corruption
[    0.013898] BRK [0x07801000, 0x07801fff] PGTABLE
[    0.014358] BRK [0x07802000, 0x07802fff] PGTABLE
[    0.014822] BRK [0x07803000, 0x07803fff] PGTABLE
[    0.015626] BRK [0x07804000, 0x07804fff] PGTABLE
[    0.016099] BRK [0x07805000, 0x07805fff] PGTABLE
[    0.016773] BRK [0x07806000, 0x07806fff] PGTABLE
[    0.106782] ACPI: Early table checksum verification disabled
[    0.107352] ACPI: RSDP 0x00000000000F5850 000014 (v00 BOCHS )
[    0.107949] ACPI: RSDT 0x00000000BFFE15C9 000030 (v01 BOCHS BXPCRSDT 
00000001 BXPC 00000001)
[    0.108766] ACPI: FACP 0x00000000BFFE149D 000074 (v01 BOCHS BXPCFACP 
00000001 BXPC 00000001)
[    0.109649] ACPI: DSDT 0x00000000BFFE0040 00145D (v01 BOCHS BXPCDSDT 
00000001 BXPC 00000001)
lizhijian@shao2-debian:~/1787$


> Weird, what you are getting is the following warning from lock torture:

warning from lock torture could be not related to this commit in this case.


Thanks
Zhijian