On Wed, 28 Mar 2018, Laurent Dufour wrote: > On 26/03/2018 00:10, David Rientjes wrote: > > On Wed, 21 Mar 2018, Laurent Dufour wrote: > > > >> I found the root cause of this lockdep warning. > >> > >> In mmap_region(), unmap_region() may be called while vma_link() has not been > >> called. This happens during the error path if call_mmap() failed. > >> > >> The only to fix that particular case is to call > >> seqcount_init(&vma->vm_sequence) when initializing the vma in mmap_region(). > >> > > > > Ack, although that would require a fixup to dup_mmap() as well. > > You're right, I'll fix that too. > I also think the following is needed: diff --git a/fs/exec.c b/fs/exec.c --- a/fs/exec.c +++ b/fs/exec.c @@ -312,6 +312,10 @@ static int __bprm_mm_init(struct linux_binprm *bprm) vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); INIT_LIST_HEAD(&vma->anon_vma_chain); +#ifdef CONFIG_SPECULATIVE_PAGE_FAULT + seqcount_init(&vma->vm_sequence); + atomic_set(&vma->vm_ref_count, 0); +#endif err = insert_vm_struct(mm, vma); if (err)
