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 6A8FA4F473B for ; Wed, 16 Sep 2026 10:42:18 +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=1789555360; cv=none; b=kfZ7EPI4P6xiaZnELgSwgIClenfQMkpgm2hyRFBZlvxmmDxD6rH1qLKt3qNomT3tp1IhztOakVK/965TR+VDRSB/V9xmZQjW6Yq6awt4GBzAEGLd/Z831GZTo8z2RAdzF/cUhXIqPjdFt3SEKOM86+JSO235g7SOIV23m5w2Rs0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789555360; c=relaxed/simple; bh=+1D6fN/40z7oTadIyHVq/VGoz/TMZpPNmaz5pqBoA+I=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=l5fOwAipLukN72KY4rG0MrQCi3Xk0xIaLQhK2Ld1g2MNQlcUlG5x4jGJOOdunyOa6mw7JcO7b6qcX8G9h73bZZlXnwOwb9Tv9vIY0exp8rQm8DP/puA93LTFS+4UfGX+9YgYN8PuYN+mfeko+ODnDYrPYtZqvL9bm5Ia12jaXdM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Qryj8B8B; 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="Qryj8B8B" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA9751F00893; Wed, 16 Sep 2026 10:42:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789555338; bh=rLAxoAMYCdNnsjd2MHsJB8fV0gtV6yrAkqf9FQVu/Lg=; h=From:To:Cc:Subject:Date:Reply-To; b=Qryj8B8BmjVLi6JPEVx8w9xW+4THgU3wLDBWxDvPbnlchX7Ye8lqzQ3d6B9kKuQ6C wN/sHi+svIQdj0ph3eTNmfSowhMT7YXswUGSTR/jEVhgnYlC5TH8eVqiNMclWh8teL vbmiOYaGY6pVSaLZ5OIPWPWq3RfMnBw54ksxUrJg= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89985: memcg: keep folio's objcg same as its node Date: Wed, 16 Sep 2026 11:31:55 +0100 Message-ID: <2026091656-CVE-2026-89985-ef64@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=2720; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=MCxXo0aCRTkW79oxg61Wy7zd7nTyF+FZj7yYMEpv91I=; b=owGbwMvMwCRo6H6F97bub03G02pJDFmr8pco5s2+2GV31+p8776D0YeFpHJ6AhRbU47tu/U2a 8LekJb4jlgWBkEmBlkxRZYv23iO7q84pOhlaHsaZg4rE8gQBi5OAZiI1i+GBUdnnngQ9WHPk3Um T9hjdv5c8Db6igrDgsl8sic5PzzOqOR/WacYsurN7BbjWwA= 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: memcg: keep folio's objcg same as its node memcg_reparent_objcgs() has an inherent assumption that a folio's objcg is the objcg of the folio's node. Folio migration across nodes breaks that assumption: the new folio simply inherits the old folio's objcg while living on a different node. Once the assumption is broken, the reparenting of the folio's objcg and the reparenting of the folio's LRU list are no longer atomic. memcg_reparent_objcgs() handles one node per iteration and drops all the locks in between, so the objcg gets reparented in the iteration for the objcg's node while the LRU list gets spliced in the iteration for the folio's node. Any LRU operation on that folio in between resolves its lruvec through the objcg, and thus takes the lru_lock of the wrong memcg, not the lru_lock of the list the folio is actually on. Fix this by selecting the objcg by folio_nid() at charge time, and by re-deriving it for the destination node in mem_cgroup_migrate() and mem_cgroup_replace_folio(). The Linux kernel CVE team has assigned CVE-2026-89985 to this issue. Affected and fixed versions =========================== Issue introduced in 7.1 with commit f1cf8d2f36dc369688bbe61ce064fbd829dbc9e1 and fixed in 7.2.5 with commit 6165478eaa3094eaee1d5e33b12520064faf043d Issue introduced in 7.1 with commit f1cf8d2f36dc369688bbe61ce064fbd829dbc9e1 and fixed in 7.3-rc1 with commit bf4ade7dbd76d4ec8697840e4ebb15ed77c5ec26 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-2026-89985 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: mm/memcontrol.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/6165478eaa3094eaee1d5e33b12520064faf043d https://git.kernel.org/stable/c/bf4ade7dbd76d4ec8697840e4ebb15ed77c5ec26