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Mon, 9 Feb 2026 13:32:46 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id QKS8GP7hiWmTIgAAD6G6ig (envelope-from ); Mon, 09 Feb 2026 13:32:46 +0000 From: Thomas Zimmermann To: boris.brezillon@collabora.com, loic.molinari@collabora.com, willy@infradead.org, frank.binns@imgtec.com, matt.coster@imgtec.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, airlied@gmail.com, simona@ffwll.ch Cc: dri-devel@lists.freedesktop.org, linux-mm@kvack.org, Thomas Zimmermann Subject: [PATCH v3 2/6] drm/gem-shmem: Test for existence of page in mmap fault handler Date: Mon, 9 Feb 2026 14:27:11 +0100 Message-ID: <20260209133241.238813-3-tzimmermann@suse.de> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260209133241.238813-1-tzimmermann@suse.de> References: <20260209133241.238813-1-tzimmermann@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: a6sc74jejrms4udnthhtj6dm8twn4cmg X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 4B603A001A X-HE-Tag: 1770643968-664469 X-HE-Meta: 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 JhCMgtUS LwYpGn43Iu9PyhvQgA7755Gh0eMAiZGi2ccGwr0I3e36OjobwOlF82YdPywycZTAbuo6KQSJR0zcQqxWgCnIsPiYvbO8axRL1/6PgTXqMbWi4IkQhAlnDhzPcQiT5Ov9pDs0PSnSCHWz4n38LEUfqb+n8BCaTMgiBOi9Y38deY/0qXnKJedJ2qKfMCxBrGx4vagJLkG7rlF2qmqKRYQY+A5i69cIRtAKHSOLq9R4gh7RNK+oYGLclemkuZuTn173sc2LgmpgR5s28Cu0= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Not having a page pointer in the mmap fault handler is an error. Test for this situation and return VM_FAULT_SIGBUS if so. Also replace several lookups of the page with a local variable. Signed-off-by: Thomas Zimmermann --- drivers/gpu/drm/drm_gem_shmem_helper.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index 5bced7db0f1f..3ee54c24e535 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -574,31 +574,31 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) { struct vm_area_struct *vma = vmf->vma; struct drm_gem_object *obj = vma->vm_private_data; + struct drm_device *dev = obj->dev; struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); loff_t num_pages = obj->size >> PAGE_SHIFT; - vm_fault_t ret; + vm_fault_t ret = VM_FAULT_SIGBUS; struct page **pages = shmem->pages; - pgoff_t page_offset; + pgoff_t page_offset = vmf->pgoff - vma->vm_pgoff; /* page offset within VMA */ + struct page *page; unsigned long pfn; - /* Offset to faulty address in the VMA. */ - page_offset = vmf->pgoff - vma->vm_pgoff; - dma_resv_lock(obj->resv, NULL); - if (page_offset >= num_pages || - drm_WARN_ON_ONCE(obj->dev, !shmem->pages) || - shmem->madv < 0) { - ret = VM_FAULT_SIGBUS; + if (page_offset >= num_pages || drm_WARN_ON_ONCE(dev, !shmem->pages) || + shmem->madv < 0) + goto out; + + page = pages[page_offset]; + if (drm_WARN_ON_ONCE(dev, !page)) goto out; - } - if (drm_gem_shmem_try_map_pmd(vmf, vmf->address, pages[page_offset])) { + if (drm_gem_shmem_try_map_pmd(vmf, vmf->address, page)) { ret = VM_FAULT_NOPAGE; goto out; } - pfn = page_to_pfn(pages[page_offset]); + pfn = page_to_pfn(page); ret = vmf_insert_pfn(vma, vmf->address, pfn); out: -- 2.52.0