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 C05AD3D88E4 for ; Wed, 3 Jun 2026 15:50:55 +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=1780501856; cv=none; b=ijYsibh1xJ5PKqc0ls/bEBtDKzEozoBQ4FguxIzeVpphYekGpJRmQjGa3K4UikpY2wHNjR1e3DVaGEV40fPzdhFJ0KenitZylljfefnLc5dOqC2KVsAiRZi/2y6ZdGY7I7hTO92AHFBAr8kY168n6H7hD52t3/S01ZPYJQ6gk1U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780501856; c=relaxed/simple; bh=wppj+FQcjcKVNlmtAIHyuXOUyeWmiH2rD9go9sZ7kNU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=u0vgHi5HtzkoTzfWgXon1l2MitvOK8E6nu02a16AH0GH4wRd7UE3LuVZTF0C48wmZXGMxqYjNWVdV2psv47lWeIM2VcdTaLlMNV9pe6mqZowMZYW1A3tYPpxSaPxF4xKPMxpLHoQTHZ8aL64+1rkqeLr4ZEbWXRWBE0xmpCXTaU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=m1GCwqMo; 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="m1GCwqMo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C97921F00893; Wed, 3 Jun 2026 15:50:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780501855; bh=K/O9jqWJhPLpctXIhbFXaxtQ41zH593JuU6MKl7OmPw=; h=From:To:Cc:Subject:Date:Reply-To; b=m1GCwqMoUDMS13XfxnXUFR4UjD5AS2AEu0EF1OD62fT9JycjxU8X03YKdNHoE/mIx bi2VEg6q8y1lj9PmkkkwnsHGEGT00mYIXAZQ9w/QOxi+5ZaAyWfYDSSOaOciqcjFS8 EGN4G0iCyESJ99xj3kNWsAXv2cLJB/4m+jZ39psQ= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-46256: NFS/localio: prevent direct reclaim recursion into NFS via nfs_writepages Date: Wed, 3 Jun 2026 17:49:45 +0200 Message-ID: <2026060335-CVE-2026-46256-e81d@gregkh> X-Mailer: git-send-email 2.54.0 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=2643; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=gtNNjb3U+eGTLJAJixmWV5gsmvAC9P9lb8uUGxN7dV8=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkKvvx6J9ZdyuUNuceew9U1lUNe87/R6Y+5D1X+TWpTl 2pNPH6rI5aFQZCJQVZMkeXLNp6j+ysOKXoZ2p6GmcPKBDKEgYtTACbyU4phfvWU/b98XfikT+aL 1D+y+sdzxzLmCsM8k4WXQ1WF+Cx3Pp54LeqY7tuwSssSAA== 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: NFS/localio: prevent direct reclaim recursion into NFS via nfs_writepages LOCALIO is an NFS loopback mount optimization that avoids using the network for READ, WRITE and COMMIT if the NFS client and server are determined to be on the same system. But because LOCALIO is still fundamentally "just NFS loopback mount" it is susceptible to recursion deadlock via direct reclaim, e.g.: NFS LOCALIO down to XFS and then back into NFS via nfs_writepages. Fix LOCALIO's potential for direct reclaim deadlock by ensuring that all its page cache allocations are done from GFP_NOFS context. Thanks to Ben Coddington for pointing out commit ad22c7a043c2 ("xfs: prevent stack overflows from page cache allocation"). The Linux kernel CVE team has assigned CVE-2026-46256 to this issue. Affected and fixed versions =========================== Issue introduced in 6.12 with commit 70ba381e1a431245c137ed597ec6a05991c79bd9 and fixed in 6.18.14 with commit ae26a4cf2baf0a44c538dc093504d1994b02dade Issue introduced in 6.12 with commit 70ba381e1a431245c137ed597ec6a05991c79bd9 and fixed in 6.19.4 with commit 6a5de0c4fc0f217eea945d3d72c34ee30d72cbc9 Issue introduced in 6.12 with commit 70ba381e1a431245c137ed597ec6a05991c79bd9 and fixed in 7.0 with commit 67435d2d8a33a75f9647724952cb1b18279d2e95 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-2026-46256 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: fs/nfs/localio.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/ae26a4cf2baf0a44c538dc093504d1994b02dade https://git.kernel.org/stable/c/6a5de0c4fc0f217eea945d3d72c34ee30d72cbc9 https://git.kernel.org/stable/c/67435d2d8a33a75f9647724952cb1b18279d2e95