Re: linux-next boot error: kernel BUG at include/linux/page-flags.h:LINE!

[Mike Rapoport]

On Thu, Dec 03, 2020 at 03:00:25AM -0800, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    bfd521e1 Add linux-next specific files for 20201203
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=14d5d403500000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=76090eb4ba939f87
> dashboard link: https://syzkaller.appspot.com/bug?extid=86800a8349c0f3f9466e
> compiler:       gcc (GCC) 10.1.0-syz 20200507
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+86800a8349c0f3f9466e@xxxxxxxxxxxxxxxxxxxxxxxxx

...

> page:ffffea0000000000 is uninitialized and poisoned
> raw: ffffffffffffffff ffffea0000000008 ffffea0000000008 ffffffffffffffff
> raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
> page dumped because: VM_BUG_ON_PAGE(1 && PageCompound(page))
> ------------[ cut here ]------------
> kernel BUG at include/linux/page-flags.h:356!

Yeah, the change to initialization of "unavailable" memory missed pfn 0 :(
This should fix it: