From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5C61F3E122D for ; Fri, 8 May 2026 13:13:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778246038; cv=none; b=GGDb5rdLjqa/NEkEmTQFXF1CjpjVigBXsnDYnHSmh8aaOWKBLNDGiX0LOCKQvclO8W1QOPK+WJg0LWWg0dYF6saS+6EhBmpjlNgjm5zmCv4NhOPivaBCGhKOkrzxAcb/RkppupFdPU5TKN5xGq+nIy2FFh0j0mYuRPgZNoWtCQM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778246038; c=relaxed/simple; bh=5uKfapMkO/LZN7HbEuyxGLthz/v3HZJBjcJdlTbOWmQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=fKezxVlMBhtK4/A98trrm5TsB1ymeyndbTKgcZl81cowtnL/GdjeZnfIxvfDxjr24D6b8GLiEsO2hoBZh0W0DnDYTqy6BI1UpiWanVahtVPhkUVYC1KydMYRRsDwaDgKzO6n3G78CEq9vX2XmGse9VEuGIOLE1sDWM5P0KdOUIw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=nEX1nW2G; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="nEX1nW2G" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9852EC2BCB0; Fri, 8 May 2026 13:13:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778246037; bh=5uKfapMkO/LZN7HbEuyxGLthz/v3HZJBjcJdlTbOWmQ=; h=From:To:Cc:Subject:Date:Reply-To:From; b=nEX1nW2Gjqh+qfmm0ZMQ4qLuVKaPfg9RsrkMxSl+Brxv0BfknFEIcYUfsRg7tFMQ+ i6nJ1ZM1E8m8XAOd93myYWXBErz5/A7aaxMPD/XYA+aY5sJ/89xPVoMXjLDk5Rbwvd mRdVfyCO84CX8ZLwpTWRexbzamNYOkNgc4fafW98= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-43292: mm/vmalloc: prevent RCU stalls in kasan_release_vmalloc_node Date: Fri, 8 May 2026 15:11:57 +0200 Message-ID: <2026050853-CVE-2026-43292-a97d@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=3288; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=4hg0QsnXwzg8wifrx1O5g3CfzeB5O4r54Axi74TziH4=; b=owGbwMvMwCRo6H6F97bub03G02pJDJl/H0p2/WSx9rv80m/FSrFLqf5O9x7EVe++9tPiAYvW1 rcu912mdcSyMAgyMciKKbJ82cZzdH/FIUUvQ9vTMHNYmUCGMHBxCsBErokxzFP+r5qYc/W5sck1 g8KmE0uOZzfHljEsmN/2bV9Ei/aW7eJXXjw2/shTlr1YGwA= 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: mm/vmalloc: prevent RCU stalls in kasan_release_vmalloc_node When CONFIG_PAGE_OWNER is enabled, freeing KASAN shadow pages during vmalloc cleanup triggers expensive stack unwinding that acquires RCU read locks. Processing a large purge_list without rescheduling can cause the task to hold CPU for extended periods (10+ seconds), leading to RCU stalls and potential OOM conditions. The issue manifests in purge_vmap_node() -> kasan_release_vmalloc_node() where iterating through hundreds or thousands of vmap_area entries and freeing their associated shadow pages causes: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6229/1:b..l ... task:kworker/0:17 state:R running task stack:28840 pid:6229 ... kasan_release_vmalloc_node+0x1ba/0xad0 mm/vmalloc.c:2299 purge_vmap_node+0x1ba/0xad0 mm/vmalloc.c:2299 Each call to kasan_release_vmalloc() can free many pages, and with page_owner tracking, each free triggers save_stack() which performs stack unwinding under RCU read lock. Without yielding, this creates an unbounded RCU critical section. Add periodic cond_resched() calls within the loop to allow: - RCU grace periods to complete - Other tasks to run - Scheduler to preempt when needed The fix uses need_resched() for immediate response under load, with a batch count of 32 as a guaranteed upper bound to prevent worst-case stalls even under light load. The Linux kernel CVE team has assigned CVE-2026-43292 to this issue. Affected and fixed versions =========================== Fixed in 6.12.75 with commit 2efa9c02c9b4c0d6866aa445f11056809b25ca28 Fixed in 6.18.16 with commit 1afe45f89d54b7183768ebbbbf14238ec187ab5c Fixed in 6.19.6 with commit b351fbe71091f7c8676c8ba597653d08b6719447 Fixed in 7.0 with commit 5747435e0fd474c24530ef1a6822f47e7d264b27 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-2026-43292 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/vmalloc.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/2efa9c02c9b4c0d6866aa445f11056809b25ca28 https://git.kernel.org/stable/c/1afe45f89d54b7183768ebbbbf14238ec187ab5c https://git.kernel.org/stable/c/b351fbe71091f7c8676c8ba597653d08b6719447 https://git.kernel.org/stable/c/5747435e0fd474c24530ef1a6822f47e7d264b27