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 7C5DE1F8EFC for ; Mon, 21 Oct 2024 19:40:06 +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=1729539606; cv=none; b=Zbj41rEf63tKM4V48cBSYyaNkpXVx4joqvRBLC5ibv8RMzY6r8NQDOnB3+zEpu0/tOvjEN2QR6hT2ZbPQQCrzWAgXlPZRCQNpF4BhBGUuhe5LAJ5KfAOzPdYxgHxlTiM4rwNQ2OlslgGswCNM2ooR4BHZ7cCSBMSEznlRhlhDmo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729539606; c=relaxed/simple; bh=tb4CYegqHXs/HkhOypskafbpH8ZHyCx2WMqjFPzc8EQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=GZVwpHpH92bUVpW9SMFeXmuh2Z+oveINL/JMcLX13NvI00D3GugWRaFmWJ6xWJpMDFM4dAzw554byqBchNN92JseE26h2pp2otrwjqwLhiOPBSt8HRUNczKl9jTvtOO4ewWC8gkDrMvP7AHDOMkPj3ZE43fVG2kl+Y+7O39u/UI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QvdUzAkC; 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="QvdUzAkC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6072C4CEE7; Mon, 21 Oct 2024 19:40:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1729539606; bh=tb4CYegqHXs/HkhOypskafbpH8ZHyCx2WMqjFPzc8EQ=; h=From:To:Cc:Subject:Date:Reply-to:From; b=QvdUzAkCMa3EgvEvsNhpLVkntNDxQo0R5BS1wt+VEzBBDQ1nhVwhnT9mFvqWXeUHF 6zgN7kWSKhBHErIIeE2Kji8x8xsmNXOH99oPxoMUjysg0ysKr7Ei9PoN6b8Oqc+pYR tmhFbf5rcUrW3Aed99p+RSED/eAe1+7I4a+nIRCg= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2024-50032: rcu/nocb: Fix rcuog wake-up from offline softirq Date: Mon, 21 Oct 2024 21:39:38 +0200 Message-ID: <2024102131-CVE-2024-50032-e7ba@gregkh> X-Mailer: git-send-email 2.47.0 Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Reply-to: , X-Developer-Signature: v=1; a=openpgp-sha256; l=3269; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=tb4CYegqHXs/HkhOypskafbpH8ZHyCx2WMqjFPzc8EQ=; b=owGbwMvMwCRo6H6F97bub03G02pJDOliaz9HL6vc+6Uo2r3gmu5crW+5UTcr+XPau1KqVZ6K1 +4S6MzsiGVhEGRikBVTZPmyjefo/opDil6Gtqdh5rAygQxh4OIUgIncSGWYX7qhsGXqwXNivpln BTrUfvCcffs8iGF+auX59riwrkA5Zat3ovIG+/LesloCAA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit Description =========== In the Linux kernel, the following vulnerability has been resolved: rcu/nocb: Fix rcuog wake-up from offline softirq After a CPU has set itself offline and before it eventually calls rcutree_report_cpu_dead(), there are still opportunities for callbacks to be enqueued, for example from a softirq. When that happens on NOCB, the rcuog wake-up is deferred through an IPI to an online CPU in order not to call into the scheduler and risk arming the RT-bandwidth after hrtimers have been migrated out and disabled. But performing a synchronized IPI from a softirq is buggy as reported in the following scenario: WARNING: CPU: 1 PID: 26 at kernel/smp.c:633 smp_call_function_single Modules linked in: rcutorture torture CPU: 1 UID: 0 PID: 26 Comm: migration/1 Not tainted 6.11.0-rc1-00012-g9139f93209d1 #1 Stopper: multi_cpu_stop+0x0/0x320 <- __stop_cpus+0xd0/0x120 RIP: 0010:smp_call_function_single swake_up_one_online __call_rcu_nocb_wake __call_rcu_common ? rcu_torture_one_read call_timer_fn __run_timers run_timer_softirq handle_softirqs irq_exit_rcu ? tick_handle_periodic sysvec_apic_timer_interrupt Fix this with forcing deferred rcuog wake up through the NOCB timer when the CPU is offline. The actual wake up will happen from rcutree_report_cpu_dead(). The Linux kernel CVE team has assigned CVE-2024-50032 to this issue. Affected and fixed versions =========================== Issue introduced in 6.6.54 with commit 9b52ee18f6d2 and fixed in 6.6.57 with commit 84a5feebba10 Issue introduced in 6.11.2 with commit 00a611229bfa and fixed in 6.11.4 with commit e66b1e01f2eb Issue introduced in 6.12-rc1 with commit 9139f93209d1 and fixed in 6.12-rc3 with commit f7345ccc62a4 Issue introduced in 6.1.113 with commit ec2777e57f2f Issue introduced in 6.10.13 with commit bbeaae6f79b2 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-2024-50032 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: kernel/rcu/tree_nocb.h 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/84a5feebba10354c683983f5f1372a144225e4c2 https://git.kernel.org/stable/c/e66b1e01f2eb3209d08122572f41f7838b79540d https://git.kernel.org/stable/c/f7345ccc62a4b880cf76458db5f320725f28e400