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[212.51.149.109]) by smtp.gmail.com with ESMTPSA id r21-v6sm636418eds.7.2018.08.22.01.54.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 Aug 2018 01:54:16 -0700 (PDT) From: Daniel Vetter To: DRI Development Cc: Intel Graphics Development , LKML , Daniel Vetter , Gustavo Padovan , Maarten Lankhorst , Sean Paul , David Airlie , John Stultz , =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= , Daniel Vetter Subject: [PATCH 4/4] drm/fb: Stop leaking physical address Date: Wed, 22 Aug 2018 10:54:05 +0200 Message-Id: <20180822085405.10787-4-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180822085405.10787-1-daniel.vetter@ffwll.ch> References: <20180822085405.10787-1-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 For buffer sharing, use dma-buf instead. We can't set smem_start to 0 unconditionally since that's used by the fbdev mmap default implementation. And we have plenty of userspace which would like to keep that working. This might break legit userspace - if it does we need to look at a case-by-cases basis how to handle that. Worst case I expect overrides for only specific drivers, since anything remotely modern should be using dma-buf/prime now (which is about 7 years old now for DRM drivers). This issue was uncovered because Noralf's rework to implement a generic fb_probe also implements it's own fb_mmap callback. Which means smem_start didn't have to be set anymore, which blew up some blob in userspace rather badly. Cc: Gustavo Padovan Cc: Maarten Lankhorst Cc: Sean Paul Cc: David Airlie Cc: John Stultz Cc: Noralf Trønnes Signed-off-by: Daniel Vetter --- drivers/gpu/drm/drm_fb_helper.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 4b0dd20bccb8..bcb78693c4f7 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -2673,6 +2673,8 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper, info = fb_helper->fbdev; info->var.pixclock = 0; + /* don't leak any physical addresses to userspace */ + info->flags |= FBINFO_HIDE_SMEM_START; /* Need to drop locks to avoid recursive deadlock in * register_framebuffer. This is ok because the only thing left to do is -- 2.18.0