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(). -- Regards, --Bob -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>