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 8E9A03043DB for ; Sat, 15 Aug 2026 06:32:29 +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=1786775550; cv=none; b=qBDx1lIyBGTjxp7nDDnknZoTU7CHIBI4FEh8Aq3YweYo5+9NVmmQibJdQyLALrLCQse+QUhIB+BSyiG5u9Xw3divI8fqw7VuvaGSvcsjJphDg9EK3BCnv3Nvc6V2mVD+mqzKQ36EkucALLvq/g8ma/cRmnkgd0f5+nw6z/IFjbg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786775550; c=relaxed/simple; bh=ZpLEOyndzD8HMXyTs/miGnuAsHxOzYXTd1eLIfsPOys=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Pa8xh2juNsFw3h1FQHI5hlZztqnPgqIsXwcKlABQB7c8JAXF9eTnLvE6TxtlTGuTqQw07Vv1iBnucgyuNySOV6Jh7JqE/aPrERuSbD0lmLI5gR2WfJ/JQdCSyX8W2qO+YlvQRvermK8/dX3/nNE0KVX3JZpCGs9V9CFueQvM2z8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=MC5k9Tk+; 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="MC5k9Tk+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E21F01F000E9; Sat, 15 Aug 2026 06:32:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786775549; bh=D0wolCzDCj1lF6LivYzrXx1IWNBffRT4JZvUBDVN+3o=; h=From:To:Cc:Subject:Date:Reply-To; b=MC5k9Tk+qfqB7BRFMiBrwunHi3i8cVR6sCRVl8IviAtSRIs6y2kNgmBnP95vYdzjR nq6HwbVx2i01MD3pBTZL3iOGVIhVdZlmPwwkqz7vPaCBRwQxd4xOg6vYqA4+Dtdu/Y vZ3gG9CocGaUDQZaIfV3x+MwgXGTxpk+lC4gf7Qw= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-74274: cxl/region: Fill first free targets[] slot during auto-discovery Date: Sat, 15 Aug 2026 15:10:01 +0900 Message-ID: <2026081544-CVE-2026-74274-9e24@gregkh> X-Mailer: git-send-email 2.55.0 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=4227; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=PXBC5cs+gi7tuuYnnKN0csrSeW1iELtizUw80NCNujc=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkNjCyRJ6cF8m8736WmFbVp7eWzHKZWf7/opTT+2h8d5 Ll70QSNjlgWBkEmBlkxRZYv23iO7q84pOhlaHsaZg4rE8gQBi5OAZjI04kM87PXMXiv/XX7++Mv TbteMXz+Z3ki2IZhwZKJjozsew/sFpvqLOhyLy55v6z9RQA= 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: cxl/region: Fill first free targets[] slot during auto-discovery Any invalid endpoint decoder pointer in the target array of an active region is not allowed by cxl driver. This means cxl driver always assumes the first p->nr_targets entries of the target array in an auto-assembly region are valid. However, there are scenarios that could leave NULL endpoint decoder pointer holes in the target array. 1. When cxl_cancel_auto_attach() removes an endpoint decoder from a target array, the target slot is set to NULL. If the removed endpoint decoder is not the last element in the target array, the target array will contain a NULL hole. 2. When a auto-assembly region removes an assigned endpoint decoder, if the removed endpoint decoder is not the last element in the target array, always remains a NULL hole in the target array. When a NULL pointer hole exists in a region's target array, it introduces two potential problems: 1. Access an endpoint decoder via a NULL pointer. it always trigger calltrace like that. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000008: 0000 [#1] SMP KASAN PTI RIP: 0010:cxl_calc_interleave_pos+0x26/0x810 [cxl_core] Call Trace: cxl_region_attach+0xc50/0x2140 [cxl_core] cxl_add_to_region+0x321/0x2330 [cxl_core] discover_region+0x92/0x150 [cxl_port] device_for_each_child+0xf3/0x170 cxl_port_probe+0x150/0x200 [cxl_port] cxl_bus_probe+0x4f/0xa0 [cxl_core] really_probe+0x1c8/0x960 __driver_probe_device+0x323/0x450 driver_probe_device+0x45/0x120 __device_attach_driver+0x15d/0x280 bus_for_each_drv+0x10f/0x190 2. Not having enough valid endpoint decoders attached to an auto-assembly region. if an auto-assembly region is created with lock flag or assigned endpoint decoder with lock flag, which means assigned endpoint decoder will not be reset during detaching, they could re-attach to the auto-assembly region again. But cxl region driver relies on p->nr_targets to verify whether the required number of endpoint decoders has been attached, and NULL endpoint decoder pointers are still counted in that case. To fix above issues, adjust cxl_region_attach_auto() logic to find the first free target slot for endpoint decoder attachment, this ensures NULL holes in the target array are filled, rather than adding new endpoint decoders at the tail of the target array. The Linux kernel CVE team has assigned CVE-2026-74274 to this issue. Affected and fixed versions =========================== Issue introduced in 6.19 with commit 2230c4bdc4120417799c74326ade3123da226d54 and fixed in 7.1.5 with commit 6fde3fcdfec438ba0df26e25a8ac7c3707211799 Issue introduced in 6.19 with commit 2230c4bdc4120417799c74326ade3123da226d54 and fixed in 7.2-rc1 with commit aa8a76711c15041ec1e42c3a74c15c2df0bd31f6 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-2026-74274 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/cxl/core/region.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/6fde3fcdfec438ba0df26e25a8ac7c3707211799 https://git.kernel.org/stable/c/aa8a76711c15041ec1e42c3a74c15c2df0bd31f6