| Message ID | 20190820081902.24815-3-daniel.vetter@ffwll.ch (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mmu notifier debug annotations/checks | expand |
On Tue, Aug 20, 2019 at 10:19:00AM +0200, Daniel Vetter wrote: > We want to teach lockdep that mmu notifiers can be called from direct > reclaim paths, since on many CI systems load might never reach that > level (e.g. when just running fuzzer or small functional tests). > > Motivated by a discussion with Jason. > > I've put the annotation into mmu_notifier_register since only when we > have mmu notifiers registered is there any point in teaching lockdep > about them. Also, we already have a kmalloc(, GFP_KERNEL), so this is > safe. > > Cc: Jason Gunthorpe <jgg@ziepe.ca> > Cc: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: David Rientjes <rientjes@google.com> > Cc: "Jérôme Glisse" <jglisse@redhat.com> > Cc: Michal Hocko <mhocko@suse.com> > Cc: "Christian König" <christian.koenig@amd.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch> > Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> > Cc: linux-mm@kvack.org > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> > mm/mmu_notifier.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c > index d12e3079e7a4..538d3bb87f9b 100644 > +++ b/mm/mmu_notifier.c > @@ -256,6 +256,13 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn, > > BUG_ON(atomic_read(&mm->mm_users) <= 0); > > + if (IS_ENABLED(CONFIG_LOCKDEP)) { > + fs_reclaim_acquire(GFP_KERNEL); > + lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); > + lock_map_release(&__mmu_notifier_invalidate_range_start_map); > + fs_reclaim_release(GFP_KERNEL); > + } Lets try it out at least Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Jason
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index d12e3079e7a4..538d3bb87f9b 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -256,6 +256,13 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn, BUG_ON(atomic_read(&mm->mm_users) <= 0); + if (IS_ENABLED(CONFIG_LOCKDEP)) { + fs_reclaim_acquire(GFP_KERNEL); + lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); + lock_map_release(&__mmu_notifier_invalidate_range_start_map); + fs_reclaim_release(GFP_KERNEL); + } + ret = -ENOMEM; mmu_notifier_mm = kmalloc(sizeof(struct mmu_notifier_mm), GFP_KERNEL); if (unlikely(!mmu_notifier_mm))
We want to teach lockdep that mmu notifiers can be called from direct reclaim paths, since on many CI systems load might never reach that level (e.g. when just running fuzzer or small functional tests). Motivated by a discussion with Jason. I've put the annotation into mmu_notifier_register since only when we have mmu notifiers registered is there any point in teaching lockdep about them. Also, we already have a kmalloc(, GFP_KERNEL), so this is safe. Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Rientjes <rientjes@google.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: "Christian König" <christian.koenig@amd.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: linux-mm@kvack.org Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> --- mm/mmu_notifier.c | 7 +++++++ 1 file changed, 7 insertions(+)