On 9/6/19 10:47 AM, Daniel Vetter wrote:
> I missed that when extending the lockdep annotations to the
> nonblocking case.
>
> I missed this while testing since in the i915 mmu notifiers is hitting
> a nice lockdep splat already before the point of going into oom killer
> mode :-/
>
> Reported-by: syzbot+aaedc50d99a03250fe1f@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: d2b219ed03d4 ("mm/mmu_notifiers: add a lockdep map for invalidate_range_start/end")
> Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: "Jérôme Glisse" <jglisse@xxxxxxxxxx>
> Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
> Cc: Jason Gunthorpe <jgg@xxxxxxxx>
> Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> Cc: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx
> Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> ---
> include/linux/mmu_notifier.h | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
> index 5a03417e5bf7..4edd98b06834 100644
> --- a/include/linux/mmu_notifier.h
> +++ b/include/linux/mmu_notifier.h
> @@ -356,13 +356,14 @@ mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range)
> static inline int
> mmu_notifier_invalidate_range_start_nonblock(struct mmu_notifier_range *range)
> {
> + int ret = 0;
> lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
> if (mm_has_notifiers(range->mm)) {
> range->flags &= ~MMU_NOTIFIER_RANGE_BLOCKABLE;
> - return __mmu_notifier_invalidate_range_start(range);
> + ret = __mmu_notifier_invalidate_range_start(range);
> }
> lock_map_release(&__mmu_notifier_invalidate_range_start_map);
> - return 0;
> + return ret;
> }
>
> static inline void
>
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
thanks,
--
John Hubbard
NVIDIA
