Re: [btrfs] 70d28b0e4f: BUG:kernel_reboot-without-warning_in_early-boot_stage, last_printk:Probing_EDD(edd=off_to_disable)...ok

[Rong Chen <rong.a.chen@intel.com>]

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On Tue, Apr 02, 2019 at 11:30:10AM +0800, Qu Wenruo wrote:
> 
> 
> On 2019/4/2 上午11:14, Rong Chen wrote:
> > 
> > On 4/1/19 11:40 PM, David Sterba wrote:
> >> On Mon, Apr 01, 2019 at 11:02:37PM +0800,  Chen, Rong A  wrote:
> >>> On 4/1/2019 10:29 PM, Qu Wenruo wrote:
> >>>> On 2019/4/1 下午10:02,  Chen, Rong A  wrote:
> >>>>> On 4/1/2019 9:28 PM, Nikolay Borisov wrote:
> >>>>>> On 1.04.19 г. 16:24 ч., kernel test robot wrote:
> >>>>>>> FYI, we noticed the following commit (built with gcc-7):
> >>>>>>>
> >>>>>>> commit: 70d28b0e4f8ed2d38571e7b1f9bec7f321a53102 ("btrfs:
> >>>>>>> tree-checker: Verify dev item")
> >>>>>>> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git
> >>>>>>> master
> >>>>>>>
> >>>>>>> in testcase: trinity
> >>>>>>> with following parameters:
> >>>>>>>
> >>>>>>>       runtime: 300s
> >>>>>>>
> >>>>>>> test-description: Trinity is a linux system call fuzz tester.
> >>>>>>> test-url: http://codemonkey.org.uk/projects/trinity/
> >>>>>>>
> >>>>>>>
> >>>>>>> on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge
> >>>>>>> -smp
> >>>>>>> 2 -m 2G
> >>>>>>>
> >>>>>>> caused below changes (please refer to attached dmesg/kmsg for entire
> >>>>>>> log/backtrace):
> >>>>>>>
> >>>>>>>
> >>>>>>> +--------------------------------------------------------------------------------------------------------+------------+------------+
> >>>>>>>
> >>>>>>>
> >>>>>>> |
> >>>>>>> | 36b9d2bc69 | 70d28b0e4f |
> >>>>>>> +--------------------------------------------------------------------------------------------------------+------------+------------+
> >>>>>>>
> >>>>>>>
> >>>>>>> |
> >>>>>>> boot_successes
> >>>>>>> | 14         | 0          |
> >>>>>>> |
> >>>>>>> boot_failures
> >>>>>>> | 2          | 14         |
> >>>>>>> |
> >>>>>>> IP-Config:Auto-configuration_of_network_failed
> >>>>>>> | 2          |            |
> >>>>>>> |
> >>>>>>> BUG:kernel_reboot-without-warning_in_early-boot_stage,last_printk:Probing_EDD(edd=off_to_disable)...ok
> >>>>>>>
> >>>>>>> | 0          | 14         |
> >>>>>>> +--------------------------------------------------------------------------------------------------------+------------+------------+
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> early console in setup code
> >>>>>>> Probing EDD (edd=off to disable)... ok
> >>>>>>> BUG: kernel reboot-without-warning in early-boot stage, last printk:
> >>>>>>> Probing EDD (edd=off to disable)... ok
> >>>>>>> Linux version 5.0.0-rc8-00196-g70d28b0 #1
> >>>>>>> Command line: ip=::::vm-snb-quantal-x86_64-1415::dhcp root=/dev/ram0
> >>>>>>> user=lkp
> >>>>>>> job=/lkp/jobs/scheduled/vm-snb-quantal-x86_64-1415/trinity-300s-quantal-core-x86_64-2018-11-09.cgz-70d28b0-20190330-29362-1y6g0qb-2.yaml
> >>>>>>>
> >>>>>>> ARCH=x86_64 kconfig=x86_64-randconfig-s5-03231928
> >>>>>>> branch=linux-devel/devel-hourly-2019032317
> >>>>>>> commit=70d28b0e4f8ed2d38571e7b1f9bec7f321a53102
> >>>>>>> BOOT_IMAGE=/pkg/linux/x86_64-randconfig-s5-03231928/gcc-7/70d28b0e4f8ed2d38571e7b1f9bec7f321a53102/vmlinuz-5.0.0-rc8-00196-g70d28b0
> >>>>>>>
> >>>>>>> max_uptime=1500
> >>>>>>> RESULT_ROOT=/result/trinity/300s/vm-snb-quantal-x86_64/quantal-core-x86_64-2018-11-09.cgz/x86_64-randconfig-s5-03231928/gcc-7/70d28b0e4f8ed2d38571e7b1f9bec7f321a53102/8
> >>>>>>>
> >>>>>>> LKP_SERVER=inn 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
> >>>>>>>
> >>>>>> Can this report be made useful by actually including output from
> >>>>>> serial
> >>>>>> console? For example possible bug-ons or whatnot? dmesg.xz just
> >>>>>> contains
> >>>>>> qemu's command line + some metadata about the test and :
> >>>>>>
> >>>>>> "BUG: kernel reboot-without-warning in early-boot stage, last printk:
> >>>>>> Probing EDD (edd=off to disable)... ok"
> >>>>>>
> >>>>>> At least a stack trace would have been useful.
> >>>>>>
> >>>>>> <snip>
> >>>>> Hi,
> >>>>>
> >>>>> We usually use the tool ("bin/lkp qemu -k <bzImage> job-script") to
> >>>>> reproduce it.  It seems no stack trace in the result:
> >>>> So there is no regression at that commit right?
> >>>>
> >>>> Just some false alert?
> >>>
> >>> Hi,
> >>>
> >>> I think there's a regression, it stopped in the early-boot stage .
> >> Can you please provide any logs that would point at btrfs? If the module
> >> is loaded or built-in started, there's a line about that. Besides that
> >> it's preceded by messages from other subsystems' initialization.
> > 
> > 
> > Hi,
> > 
> > CONFIG_BTRFS_FS and CONFIG_BTRFS_FS_REF_VERIFY is enabled in the kconfig.
> > I disabled them for the experiment, and the new kernel is bootable. I
> > don't have more logs to prove it.
> > 
> > $ grep BTRFS config-5.0.0-rc8-00196-g70d28b0
> > CONFIG_BTRFS_FS=y
> > # CONFIG_BTRFS_FS_POSIX_ACL is not set
> > # CONFIG_BTRFS_FS_CHECK_INTEGRITY is not set
> > # CONFIG_BTRFS_FS_RUN_SANITY_TESTS is not set
> > # CONFIG_BTRFS_DEBUG is not set
> > # CONFIG_BTRFS_ASSERT is not set
> > CONFIG_BTRFS_FS_REF_VERIFY=y
> 
> That's strange, ref verify part is pretty far from the tree checker code.
> 
> Would you please try to compile btrfs as module and then insert the
> module to get some valid kernel messages?
> 

Kernel is ok with the btrfs module. I found it maybe related to gcc plugin,
and I can reproduce it with gcc-7-plugin-dev installed on Debian.

$ grep GCC_PLUGINS config-5.0.0-rc8-00196-g70d28b0
CONFIG_HAVE_GCC_PLUGINS=y
CONFIG_GCC_PLUGINS=y
CONFIG_GCC_PLUGIN_CYC_COMPLEXITY=y
CONFIG_GCC_PLUGIN_LATENT_ENTROPY=y
CONFIG_GCC_PLUGIN_STRUCTLEAK=y
# CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL is not set
# CONFIG_GCC_PLUGIN_STRUCTLEAK_VERBOSE is not set
# CONFIG_GCC_PLUGIN_RANDSTRUCT is not set
# CONFIG_GCC_PLUGIN_STACKLEAK is not set

Best Regards,
Rong Chen