On 16/03/2018 11:23, kernel test robot wrote:
> FYI, we noticed the following commit (built with gcc-7):
>
> commit: b33ddf50ebcc740b990dd2e0e8ff0b92c7acf58e ("mm: Protect mm_rb tree with a rwlock")
> url: https://github.com/0day-ci/linux/commits/Laurent-Dufour/Speculative-page-faults/20180316-151833
>
>
> in testcase: boot
>
> on test machine: qemu-system-x86_64 -enable-kvm -cpu host -smp 2 -m 4G
>
> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
>
>
> +----------------------------------------+------------+------------+
> | | 7f3f7b4e80 | b33ddf50eb |
> +----------------------------------------+------------+------------+
> | boot_successes | 8 | 0 |
> | boot_failures | 0 | 6 |
> | INFO:trying_to_register_non-static_key | 0 | 6 |
> +----------------------------------------+------------+------------+
>
>
>
> [ 22.218186] INFO: trying to register non-static key.
> [ 22.220252] the code is fine but needs lockdep annotation.
> [ 22.222471] turning off the locking correctness validator.
> [ 22.224839] CPU: 0 PID: 1 Comm: init Not tainted 4.16.0-rc4-next-20180309-00017-gb33ddf5 #1
> [ 22.228528] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
> [ 22.232443] Call Trace:
> [ 22.234234] dump_stack+0x85/0xbc
> [ 22.236085] register_lock_class+0x237/0x477
> [ 22.238057] __lock_acquire+0xd0/0xf15
> [ 22.240032] lock_acquire+0x19c/0x1ce
> [ 22.241927] ? do_mmap+0x3aa/0x3ff
> [ 22.243749] mmap_region+0x37a/0x4c0
> [ 22.245619] ? do_mmap+0x3aa/0x3ff
> [ 22.247425] do_mmap+0x3aa/0x3ff
> [ 22.249175] vm_mmap_pgoff+0xa1/0xea
> [ 22.251083] elf_map+0x6d/0x134
> [ 22.252873] load_elf_binary+0x56f/0xe07
> [ 22.254853] search_binary_handler+0x75/0x1f8
> [ 22.256934] do_execveat_common+0x661/0x92b
> [ 22.259164] ? rest_init+0x22e/0x22e
> [ 22.261082] do_execve+0x1f/0x21
> [ 22.262884] kernel_init+0x5a/0xf0
> [ 22.264722] ret_from_fork+0x3a/0x50
> [ 22.303240] systemd[1]: RTC configured in localtime, applying delta of 480 minutes to system time.
> [ 22.313544] systemd[1]: Failed to insert module 'autofs4': No such file or directory
Thanks a lot for reporting this.
I found the issue introduced in that patch.
I mistakenly remove in the call to seqcount_init(&vma->vm_sequence) in
__vma_link_rb().
This doesn't have a functional impact as the vm_sequence is incremented
monotonically.
I'll fix that in the next series.
Laurent.
