From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A149F4D0CEA for ; Sun, 18 Oct 2026 15:25:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792337129; cv=none; b=EBlZvl83tmY0F8PfVwNiGhYlauO4ONBdAoWCY5YZqn5Qr2y309S93Dj/d3zOsgZMQRlnq+Wb6YXpoNW66Vs5tf48dPqf8cA4OOVIuIE5gWNxEf3z3VE1diuBacrNsxtlvaXQZqFnwuZ0IM1KDMtA2E9xIw33YcC0uYLdWzg4eqk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792337129; c=relaxed/simple; bh=advBKIBeCdTjYiVFM9gScIWKUx0jRS209kRSDKw2Fn0=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=YYXXOR400Pe2XDanyFtdyOerD97BU9MhhIc4rpl1bJ5YDGEIKRGPfL22VnkZdVwMMMMx9wLK04OZ+c/Cqi1j0KQKQrpm+oAKvvDmFXb7gENzD8O+gdxC87Q4ymeTFjQG26D3C7KJ+1s8JENZqGMT0b8Y17AgsnRzlNPvFd6HEdM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TH8aXXyr; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="TH8aXXyr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3DDCE1F000C4; Sun, 18 Oct 2026 15:25:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792337123; bh=ESwMg6CVFK3vVmrZ6Pnhv9Tn7CkH2OZNFeOlQuBpzb0=; h=From:To:Cc:Subject:Date:Reply-To; b=TH8aXXyrAd2eKwyuPXXsz4c/9BbGE3VLkEI1APvR2Jp7p3I5kOafuHkg++uU/O1g+ WFpr+x892HHdpOY2zJ0qC+oceBuWURTCppYQQxmLj6Bzt1M7lru89zsUaPrUIxIZTY 2NXwjJ6lrVYD4F9wY0XBSpOgI7qYF8vfGdrQGBI8= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-98521: drm/i915: fix incorrect RCU teardown order Date: Sun, 18 Oct 2026 17:16:25 +0200 Message-ID: <2026101822-CVE-2026-98521-4a94@gregkh> X-Mailer: git-send-email 2.56.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3715; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=/v2ajcNFVrHqGltDj6Q9MiZ1sA5m3jfhjxyvbxJLQAM=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlXHnX9aalaHyzNs8zz2Oot1VHGi3zORNxf7R02s5LXa 9M9s7DGjlgWBkEmBlkxRZYv23iO7q84pOhlaHsaZg4rE8gQBi5OAZhI51yG+fHMeYo+wZrKIW/P Nv/7dUAg4fGMSIb5niKxWX2as4JrY4trRBhexkzaFfkCAA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: drm/i915: fix incorrect RCU teardown order i915_gem_busy_ioctl uses dma_resv_for_each_fence_unlocked() to iterate over the fences in an GEM object without holding a reference but only the RCU read side lock. What can happen here is that the GEM object is destroyed concurrently while i915_gem_busy_ioctl is still running. This won't free the GEM objects memory, but still drops all the dma_fence references. Now when dma_resv_for_each_fence_unlocked() sees a destroyed dma_fence it assumes that a new fence list was installed and re-starts the loop. But in the case of a destroyed GEM object a new fence list is never installed, only the old one freed and therefore the iteration never finishes resulting in an endless loop. The solution is to drop the fence references only after the RCU grace period. The fixes tag is not necessary the patch introducing the problem, but the one making it so worse that we need to address it. This problem was pointed out by Sashiko-bot. (cherry picked from commit 5113479556025093bf8133bb2dcaa33be2d50921) The Linux kernel CVE team has assigned CVE-2026-98521 to this issue. Affected and fixed versions =========================== Issue introduced in 5.17 with commit 912ff2ebd695c582ca4cebf833ad73a378a99f23 and fixed in 6.1.189 with commit 4d4ca84213327da1f84ef7af3946dea6b14c5d88 Issue introduced in 5.17 with commit 912ff2ebd695c582ca4cebf833ad73a378a99f23 and fixed in 6.6.158 with commit c53db9cc245219af6b528ca022a17ebfa91d80ba Issue introduced in 5.17 with commit 912ff2ebd695c582ca4cebf833ad73a378a99f23 and fixed in 6.12.112 with commit b12e041aedcf9fa77c6002a49f07eb20d0521b86 Issue introduced in 5.17 with commit 912ff2ebd695c582ca4cebf833ad73a378a99f23 and fixed in 6.18.55 with commit cc890d3f1b15bf6481dc7270fba0b4fbba572813 Issue introduced in 5.17 with commit 912ff2ebd695c582ca4cebf833ad73a378a99f23 and fixed in 7.2.9 with commit 2dd0190e397ec6468095fd3e80e79276a7361449 Issue introduced in 5.17 with commit 912ff2ebd695c582ca4cebf833ad73a378a99f23 and fixed in 7.3-rc5 with commit d2da6696e0c4e60414706e607029d0bb0330c67e Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-98521 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: drivers/gpu/drm/i915/gem/i915_gem_object.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/4d4ca84213327da1f84ef7af3946dea6b14c5d88 https://git.kernel.org/stable/c/c53db9cc245219af6b528ca022a17ebfa91d80ba https://git.kernel.org/stable/c/b12e041aedcf9fa77c6002a49f07eb20d0521b86 https://git.kernel.org/stable/c/cc890d3f1b15bf6481dc7270fba0b4fbba572813 https://git.kernel.org/stable/c/2dd0190e397ec6468095fd3e80e79276a7361449 https://git.kernel.org/stable/c/d2da6696e0c4e60414706e607029d0bb0330c67e