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[212.51.149.96]) by smtp.gmail.com with ESMTPSA id j25sm3000780ejb.49.2019.08.26.13.14.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Aug 2019 13:14:33 -0700 (PDT) From: Daniel Vetter To: LKML Cc: Linux MM , DRI Development , Daniel Vetter , Jason Gunthorpe , Chris Wilson , Andrew Morton , David Rientjes , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Michal Hocko , =?UTF-8?q?Christian=20K=C3=B6nig?= , Greg Kroah-Hartman , Mike Rapoport , Jason Gunthorpe , Daniel Vetter Subject: [PATCH 2/5] mm, notifier: Prime lockdep Date: Mon, 26 Aug 2019 22:14:22 +0200 Message-Id: <20190826201425.17547-3-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190826201425.17547-1-daniel.vetter@ffwll.ch> References: <20190826201425.17547-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Cc: Chris Wilson Cc: Andrew Morton Cc: David Rientjes Cc: "Jérôme Glisse" Cc: Michal Hocko Cc: "Christian König" Cc: Greg Kroah-Hartman Cc: Daniel Vetter Cc: Mike Rapoport Cc: linux-mm@kvack.org Reviewed-by: Jason Gunthorpe Signed-off-by: Daniel Vetter --- mm/mmu_notifier.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index d48d3b2abd68..0523555933c9 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -259,6 +259,13 @@ int __mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm) lockdep_assert_held_write(&mm->mmap_sem); 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); + } + mn->mm = mm; mn->users = 1; -- 2.23.0