From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D0232C43331 for ; Thu, 26 Mar 2020 23:29:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A511A20409 for ; Thu, 26 Mar 2020 23:29:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585265340; bh=9l0BVCPnVOk8LApGkJbFE6PV/Q93ExquRErG0hBhDz8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=I0BjEQYakljQ3X2hhJ1tqQDaSRqkEaQWD80bgkx5UggCoLmIlPy9OmhDmzfmWZdWE 7VfFossb4GsHHj5VRkY5WQxG/suzN0amrMqYrxMhzOtCSEckVmLxicNwY6EtZvfrgr oTZ9UzM8AtyOslC4ZOx8lkNUWrTOjARL6FUlJ72E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727821AbgCZXYY (ORCPT ); Thu, 26 Mar 2020 19:24:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:43650 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727793AbgCZXYO (ORCPT ); Thu, 26 Mar 2020 19:24:14 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6F03F20719; Thu, 26 Mar 2020 23:24:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585265054; bh=9l0BVCPnVOk8LApGkJbFE6PV/Q93ExquRErG0hBhDz8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RTgC+gV9ulYuxvOGYYW1VDR1Wh8XdFgKND048fHepIZlvtSsqfoK2AfrEUAMmWG1/ SpSrQFxuEG6uOAeXBxrvmIDCY7k91gbc0CYWWeABptmiIafLp8MtJcndr6RX6XhkRh 23M0wGwprHjClXSFNqB7zfNkiuQSy24a5GW4Fqek= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Cristian Marussi , Dave Martin , Mark Rutland , Will Deacon , Sasha Levin , linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 5.5 14/28] arm64: smp: fix smp_send_stop() behaviour Date: Thu, 26 Mar 2020 19:23:43 -0400 Message-Id: <20200326232357.7516-14-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200326232357.7516-1-sashal@kernel.org> References: <20200326232357.7516-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Cristian Marussi [ Upstream commit d0bab0c39e32d39a8c5cddca72e5b4a3059fe050 ] On a system with only one CPU online, when another one CPU panics while starting-up, smp_send_stop() will fail to send any STOP message to the other already online core, resulting in a system still responsive and alive at the end of the panic procedure. [ 186.700083] CPU3: shutdown [ 187.075462] CPU2: shutdown [ 187.162869] CPU1: shutdown [ 188.689998] ------------[ cut here ]------------ [ 188.691645] kernel BUG at arch/arm64/kernel/cpufeature.c:886! [ 188.692079] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [ 188.692444] Modules linked in: [ 188.693031] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 5.6.0-rc4-00001-g338d25c35a98 #104 [ 188.693175] Hardware name: Foundation-v8A (DT) [ 188.693492] pstate: 200001c5 (nzCv dAIF -PAN -UAO) [ 188.694183] pc : has_cpuid_feature+0xf0/0x348 [ 188.694311] lr : verify_local_elf_hwcaps+0x84/0xe8 [ 188.694410] sp : ffff800011b1bf60 [ 188.694536] x29: ffff800011b1bf60 x28: 0000000000000000 [ 188.694707] x27: 0000000000000000 x26: 0000000000000000 [ 188.694801] x25: 0000000000000000 x24: ffff80001189a25c [ 188.694905] x23: 0000000000000000 x22: 0000000000000000 [ 188.694996] x21: ffff8000114aa018 x20: ffff800011156a38 [ 188.695089] x19: ffff800010c944a0 x18: 0000000000000004 [ 188.695187] x17: 0000000000000000 x16: 0000000000000000 [ 188.695280] x15: 0000249dbde5431e x14: 0262cbe497efa1fa [ 188.695371] x13: 0000000000000002 x12: 0000000000002592 [ 188.695472] x11: 0000000000000080 x10: 00400032b5503510 [ 188.695572] x9 : 0000000000000000 x8 : ffff800010c80204 [ 188.695659] x7 : 00000000410fd0f0 x6 : 0000000000000001 [ 188.695750] x5 : 00000000410fd0f0 x4 : 0000000000000000 [ 188.695836] x3 : 0000000000000000 x2 : ffff8000100939d8 [ 188.695919] x1 : 0000000000180420 x0 : 0000000000180480 [ 188.696253] Call trace: [ 188.696410] has_cpuid_feature+0xf0/0x348 [ 188.696504] verify_local_elf_hwcaps+0x84/0xe8 [ 188.696591] check_local_cpu_capabilities+0x44/0x128 [ 188.696666] secondary_start_kernel+0xf4/0x188 [ 188.697150] Code: 52805001 72a00301 6b01001f 54000ec0 (d4210000) [ 188.698639] ---[ end trace 3f12ca47652f7b72 ]--- [ 188.699160] Kernel panic - not syncing: Attempted to kill the idle task! [ 188.699546] Kernel Offset: disabled [ 188.699828] CPU features: 0x00004,20c02008 [ 188.700012] Memory Limit: none [ 188.700538] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]--- [root@arch ~]# echo Helo Helo [root@arch ~]# cat /proc/cpuinfo | grep proce processor : 0 Make smp_send_stop() account also for the online status of the calling CPU while evaluating how many CPUs are effectively online: this way, the right number of STOPs is sent, so enforcing a proper freeze of the system at the end of panic even under the above conditions. Fixes: 08e875c16a16c ("arm64: SMP support") Reported-by: Dave Martin Acked-by: Mark Rutland Signed-off-by: Cristian Marussi Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/kernel/smp.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index d4ed9a19d8fe7..e4dc241c5a8e8 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -958,11 +958,22 @@ void tick_broadcast(const struct cpumask *mask) } #endif +/* + * The number of CPUs online, not counting this CPU (which may not be + * fully online and so not counted in num_online_cpus()). + */ +static inline unsigned int num_other_online_cpus(void) +{ + unsigned int this_cpu_online = cpu_online(smp_processor_id()); + + return num_online_cpus() - this_cpu_online; +} + void smp_send_stop(void) { unsigned long timeout; - if (num_online_cpus() > 1) { + if (num_other_online_cpus()) { cpumask_t mask; cpumask_copy(&mask, cpu_online_mask); @@ -975,10 +986,10 @@ void smp_send_stop(void) /* Wait up to one second for other CPUs to stop */ timeout = USEC_PER_SEC; - while (num_online_cpus() > 1 && timeout--) + while (num_other_online_cpus() && timeout--) udelay(1); - if (num_online_cpus() > 1) + if (num_other_online_cpus()) pr_warn("SMP: failed to stop secondary CPUs %*pbl\n", cpumask_pr_args(cpu_online_mask)); -- 2.20.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0E65C2D0ED for ; Thu, 26 Mar 2020 23:24:23 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2BE7F20714 for ; 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bh=3YW6hDzHf09fCZzqNMxJIbehEYAbbKpT36qU6NhgxW8=; b=q5gcoaIMRGWaEH 4mtkx3Z32EBpihwW/Sjj1RH59zyk9y3aEgIdZjsSQ5ho7adge61BbfapKNb02m2S5iytVfK5sL4+7 ajkL8fdWc6UfTNw7qIWu74+4ODSWhNgcnqIZR/eYgvDYtvnPClSYAqvfzKRQR4Ec9mKlCc7ol5dIO vqBtd81ZUKTYvDMeBmm9LLsCaNvgbA7SYnGzr76X/TFmZMcpCbevyUbD7oAp3LvEM5PwJtxzwAqgs L4eU9E8J9mdIpt4/bxLdIEgadQK1ASnriINtIius/9cjb7t/C0ARzWc5BqK8LTB9VYxnUBVopryLP 8e4Xmuz/peJnVeVQ/PLA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jHbrG-00016M-Fu; Thu, 26 Mar 2020 23:24:18 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jHbrC-00013w-J6 for linux-arm-kernel@lists.infradead.org; Thu, 26 Mar 2020 23:24:16 +0000 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6F03F20719; Thu, 26 Mar 2020 23:24:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585265054; bh=9l0BVCPnVOk8LApGkJbFE6PV/Q93ExquRErG0hBhDz8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RTgC+gV9ulYuxvOGYYW1VDR1Wh8XdFgKND048fHepIZlvtSsqfoK2AfrEUAMmWG1/ SpSrQFxuEG6uOAeXBxrvmIDCY7k91gbc0CYWWeABptmiIafLp8MtJcndr6RX6XhkRh 23M0wGwprHjClXSFNqB7zfNkiuQSy24a5GW4Fqek= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH AUTOSEL 5.5 14/28] arm64: smp: fix smp_send_stop() behaviour Date: Thu, 26 Mar 2020 19:23:43 -0400 Message-Id: <20200326232357.7516-14-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200326232357.7516-1-sashal@kernel.org> References: <20200326232357.7516-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200326_162414_708841_6DF5AAAF X-CRM114-Status: GOOD ( 15.35 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Sasha Levin , linux-arm-kernel@lists.infradead.org, Will Deacon , Dave Martin , Cristian Marussi Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Cristian Marussi [ Upstream commit d0bab0c39e32d39a8c5cddca72e5b4a3059fe050 ] On a system with only one CPU online, when another one CPU panics while starting-up, smp_send_stop() will fail to send any STOP message to the other already online core, resulting in a system still responsive and alive at the end of the panic procedure. [ 186.700083] CPU3: shutdown [ 187.075462] CPU2: shutdown [ 187.162869] CPU1: shutdown [ 188.689998] ------------[ cut here ]------------ [ 188.691645] kernel BUG at arch/arm64/kernel/cpufeature.c:886! [ 188.692079] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [ 188.692444] Modules linked in: [ 188.693031] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 5.6.0-rc4-00001-g338d25c35a98 #104 [ 188.693175] Hardware name: Foundation-v8A (DT) [ 188.693492] pstate: 200001c5 (nzCv dAIF -PAN -UAO) [ 188.694183] pc : has_cpuid_feature+0xf0/0x348 [ 188.694311] lr : verify_local_elf_hwcaps+0x84/0xe8 [ 188.694410] sp : ffff800011b1bf60 [ 188.694536] x29: ffff800011b1bf60 x28: 0000000000000000 [ 188.694707] x27: 0000000000000000 x26: 0000000000000000 [ 188.694801] x25: 0000000000000000 x24: ffff80001189a25c [ 188.694905] x23: 0000000000000000 x22: 0000000000000000 [ 188.694996] x21: ffff8000114aa018 x20: ffff800011156a38 [ 188.695089] x19: ffff800010c944a0 x18: 0000000000000004 [ 188.695187] x17: 0000000000000000 x16: 0000000000000000 [ 188.695280] x15: 0000249dbde5431e x14: 0262cbe497efa1fa [ 188.695371] x13: 0000000000000002 x12: 0000000000002592 [ 188.695472] x11: 0000000000000080 x10: 00400032b5503510 [ 188.695572] x9 : 0000000000000000 x8 : ffff800010c80204 [ 188.695659] x7 : 00000000410fd0f0 x6 : 0000000000000001 [ 188.695750] x5 : 00000000410fd0f0 x4 : 0000000000000000 [ 188.695836] x3 : 0000000000000000 x2 : ffff8000100939d8 [ 188.695919] x1 : 0000000000180420 x0 : 0000000000180480 [ 188.696253] Call trace: [ 188.696410] has_cpuid_feature+0xf0/0x348 [ 188.696504] verify_local_elf_hwcaps+0x84/0xe8 [ 188.696591] check_local_cpu_capabilities+0x44/0x128 [ 188.696666] secondary_start_kernel+0xf4/0x188 [ 188.697150] Code: 52805001 72a00301 6b01001f 54000ec0 (d4210000) [ 188.698639] ---[ end trace 3f12ca47652f7b72 ]--- [ 188.699160] Kernel panic - not syncing: Attempted to kill the idle task! [ 188.699546] Kernel Offset: disabled [ 188.699828] CPU features: 0x00004,20c02008 [ 188.700012] Memory Limit: none [ 188.700538] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]--- [root@arch ~]# echo Helo Helo [root@arch ~]# cat /proc/cpuinfo | grep proce processor : 0 Make smp_send_stop() account also for the online status of the calling CPU while evaluating how many CPUs are effectively online: this way, the right number of STOPs is sent, so enforcing a proper freeze of the system at the end of panic even under the above conditions. Fixes: 08e875c16a16c ("arm64: SMP support") Reported-by: Dave Martin Acked-by: Mark Rutland Signed-off-by: Cristian Marussi Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/kernel/smp.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index d4ed9a19d8fe7..e4dc241c5a8e8 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -958,11 +958,22 @@ void tick_broadcast(const struct cpumask *mask) } #endif +/* + * The number of CPUs online, not counting this CPU (which may not be + * fully online and so not counted in num_online_cpus()). + */ +static inline unsigned int num_other_online_cpus(void) +{ + unsigned int this_cpu_online = cpu_online(smp_processor_id()); + + return num_online_cpus() - this_cpu_online; +} + void smp_send_stop(void) { unsigned long timeout; - if (num_online_cpus() > 1) { + if (num_other_online_cpus()) { cpumask_t mask; cpumask_copy(&mask, cpu_online_mask); @@ -975,10 +986,10 @@ void smp_send_stop(void) /* Wait up to one second for other CPUs to stop */ timeout = USEC_PER_SEC; - while (num_online_cpus() > 1 && timeout--) + while (num_other_online_cpus() && timeout--) udelay(1); - if (num_online_cpus() > 1) + if (num_other_online_cpus()) pr_warn("SMP: failed to stop secondary CPUs %*pbl\n", cpumask_pr_args(cpu_online_mask)); -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel