Re: mm: another VM_BUG_ON_PAGE(PageTail(page))

[Kirill A. Shutemov]

On Thu, Jan 28, 2016 at 11:27:11AM +0100, Dmitry Vyukov wrote:
> Hello,
> 
> The following program triggers VM_BUG_ON_PAGE(PageTail(page)):
> 
> // autogenerated by syzkaller (http://github.com/google/syzkaller)
> #include <fcntl.h>
> #include <numaif.h>
> #include <sys/mman.h>
> #include <unistd.h>
> 
> int main()
> {
>   int fd;
> 
>   mmap((void*)0x20000000, 4096, PROT_READ|PROT_WRITE,
> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
>   fd = open("/dev/sg1", O_RDONLY|O_SYNC|0x100000);
>   mmap((void*)0x20001000, 0x4000, PROT_READ|PROT_WRITE,
> MAP_PRIVATE|MAP_FIXED, fd, 0);
>   mbind((void*)0x20000000, 0x4000, 0x8002, (void*)0x20002ff8, 3660,
> MPOL_MF_STRICT|MPOL_MF_MOVE);
>   return 0;
> }

I don't have sg1 in my VM. I changed it to sg0 and it doesn't trigger an
issue: mbind() returns -EINVAL as it supposed to. Hm..

-- 
 Kirill A. Shutemov