On Thu, Aug 28, 2025 at 02:12:12PM +0800, Yafang Shao wrote:
> On Wed, Aug 27, 2025 at 11:46 PM Lorenzo Stoakes
> <lorenzo.stoakes@xxxxxxxxxx> wrote:
> >
> > On Tue, Aug 26, 2025 at 03:19:42PM +0800, Yafang Shao wrote:
> > > Every VMA must have an associated mm_struct, and it is safe to access
> >
> > Err this isn't true? Pretty sure special VMAs don't have that set.
>
> I’m not aware of any VMA that doesn’t belong to an mm_struct. If there
> is such a case, it would be helpful if you could point it out. In any
> case, I’ll remove the VMA-related code in the next version since it’s
> unnecessary.
If you lok at get_vma_name() in fs/proc/task_mmu.c you'll see:
if (!vma->vm_mm) {
*name = "[vdso]";
return;
}
So a VDSO will have this condition.
I did a quick drgn()/printk() test and didn't see any, but maybe my system - but
in any case this appears to be a valid situation that can arise, presumably
because it's a VMA somehow shared with multiple mm's or something truly god
awful like that :)
Cheers, Lorenzo
