On Thu, Feb 27, 2014 at 11:03 PM, Kirill A. Shutemov
<kirill.shutemov@xxxxxxxxxxxxxxx> wrote:
Sasha Levin wrote:
Hi all,
While fuzzing with trinity inside a KVM tools guest running latest -next kernel I've stumbled on the
following spew:
[ 1428.146261] kernel BUG at mm/huge_memory.c:2785!
Hm, interesting.
It seems we either failed to split huge page on vma split or it
materialized from under us. I don't see how it can happen:
- it seems we do the right thing with vma_adjust_trans_huge() in
__split_vma();
- we hold ->mmap_sem all the way from vm_munmap(). At least I don't see
a place where we could drop it;
Enable CONFIG_DEBUG_VM may show some useful information, at least we
can confirm weather rwsem_is_locked(&tlb->mm->mmap_sem) before
split_huge_page_pmd().