From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 84AA9106B50B for ; Wed, 25 Mar 2026 11:58:00 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E7E1310E857; Wed, 25 Mar 2026 11:57:59 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="LgW9jBot"; dkim-atps=neutral Received: from mail-wr1-f54.google.com (mail-wr1-f54.google.com [209.85.221.54]) by gabe.freedesktop.org (Postfix) with ESMTPS id F00DD10E6D5 for ; Tue, 24 Mar 2026 13:47:50 +0000 (UTC) Received: by mail-wr1-f54.google.com with SMTP id ffacd0b85a97d-43b871dd06eso175202f8f.0 for ; Tue, 24 Mar 2026 06:47:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1774360069; x=1774964869; darn=lists.freedesktop.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=NGfhZzKVYIP6RlfjAEGnGSAhqoey9TRFFzSxoh0MDiY=; b=LgW9jBotyRn2glR0owwB2W6gTwd3vf8bRFmfd0xXEYWbiuTmwNC1gnYAZhVJR1udxH +9XVTuYg4o6mv1JzHIhGiH92KDIk9kFqFYPj4Wz6OOM1vv5vOUjNvqzQGuZvjxr+aKNa CjVUUkhn/jDEr1+uaGKNV7N8RjJtX898fq/9iE1QbJ7cvxec8H5tflCbiXfmLNE6z3G4 Dm/BnGk/tuqqM9TYj0ncvMLsiA+UjhthJHuAYbzMxq4cF4bFuvV7awGJyvpuQnGvvYOP 6hg7+tZNhCOqPdUMD8EuDHqt7SMaWHiEHcXz+hzbl5W1AUI8/xDgKSZ4/FJB2m3sHQ2h 0BTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774360069; x=1774964869; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=NGfhZzKVYIP6RlfjAEGnGSAhqoey9TRFFzSxoh0MDiY=; b=WO75cnwmmQC3n1qqpKqy28sGDClYgiQirwNmSyMEE33sZgGGB+0INKNiRu8eq9UspV pjxyOUW6y/pEJm3R/Zq8haXmDDr4yZ/v9NFyYNuXybi/vgwPXT2w+0GvMVH468GTmmJB F1bxBMmLc5YwYVXANjGfdBM1jZbkK/HEcgQPr7vAgaPWzSxqYnuorHV2ndHLO8eiHACZ ioIIC3ZYnFZoIo3ZKpZBl6iKjtuwoHk76LgTTpcWSYOaWNmY8b5WyhlYpuO68jh6HvCx JJKA7I2GitEMhUezEGW2Jj3ltWPn0eIqmuKIlGaqAF8NaDHCRnGOqpwvSQi/tNH1+VQw gbFw== X-Gm-Message-State: AOJu0YzJqLBIykR1UU3FK50Xv85XHz7q6ZngUpK0krO58McCs7NVrZW8 Llcxgek+FIee3ETKvJxDATCD7fbPz+odNSD3U0PmqZXoQ7Yk/5u0bbdxP7A4bVlX X-Gm-Gg: ATEYQzxIu6DsICtSj+3h8YlwyQHWB4s/BhC1BmRPD2EP2Cfn58/US2Qm2JWSMPJ7lay VsDkbhbMvG4tb8IK64vrCc1KEZMg0iewiSO+mFeClWTws6NJIxKemy/N077Qrsd1eb4pCweY4Bp rQkF5whNAMrAuMhvLEO+0gsz4AiLq/vjpoYDt0Kcq3pA4dvKgCrnKyWOLSzcfIKb4J9Vvl9e2G3 AwuVrPVuFvAeGByQ55VCeKNYm64u/ZvEp5YNll/xsNOjfSbVeavjdUXqvq3jckPBmdE/Bj4TTj0 zmHiW+ylHWZkQarUOLBzn15WzI4BN3cbbch2D7Lw+mdx0mVHx/HH+9SVWMAMdxbz9XyoddM4I10 DDimAlhoQkSeS8RNVaimrBsvUwbuZbGhExb80IAxKamEvdjXcvyTI0bLEdeC1k4idcp5NXe64aK LApyY4wrQ6kMAvrr429hVX3t+jrH3nKQ== X-Received: by 2002:a5d:64c6:0:b0:439:b486:ba6b with SMTP id ffacd0b85a97d-43b64281531mr22669866f8f.39.1774360068914; Tue, 24 Mar 2026 06:47:48 -0700 (PDT) Received: from zinco04.TojiM4 ([197.146.60.227]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43b86fbb195sm1834492f8f.14.2026.03.24.06.47.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Mar 2026 06:47:48 -0700 (PDT) From: Yassine Mounir To: intel-gfx@lists.freedesktop.org Cc: joonas.lahtinen@linux.intel.com, security@kernel.org, rodrigo.vivi@intel.com, Yassine Mounir Subject: [PATCH] drm/i915: Fix UAF race between relocation and GEM_CLOSE Date: Tue, 24 Mar 2026 09:47:18 -0400 Message-ID: <20260324134718.27331-1-sosohero200@gmail.com> X-Mailer: git-send-email 2.53.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Mailman-Approved-At: Wed, 25 Mar 2026 11:57:58 +0000 X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" A use-after-free (UAF) vulnerability was identified in the i915 driver within eb_relocate_vma. The issue arises from a race condition where a concurrent DRM_IOCTL_GEM_CLOSE can drop the GEM object's reference count to zero while the relocation thread is still processing entries. This results in the kernel attempting to access freed memory in eb_relocate_entry, leading to a display pipeline hang and potential system instability. Fix: Wrap the relocation phase with i915_gem_object_get() and i915_gem_object_put() to ensure the object remains valid throughout the operation, even if user-space requests to close the handle. Reported-by: Yassine Mounir (Toji1) Signed-off-by: Yassine Mounir --- drivers/gpu/drm/i915/i915_gem_execbuffer.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c @@ -1542,7 +1542,11 @@ eb_relocate_vma(struct i915_execbuffer *eb, struct i915_vma *vma) if (ret) return ret; + /* Hold a reference to prevent UAF during concurrent GEM_CLOSE */ + i915_gem_object_get(vma->obj); ret = eb_relocate_entry(eb, vma, rel); + i915_gem_object_put(vma->obj); + if (ret) return ret; }