From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:59162 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966613AbeFRI2W (ORCPT ); Mon, 18 Jun 2018 04:28:22 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Russell King , Sasha Levin Subject: [PATCH 4.16 277/279] ARM: kexec: fix kdump register saving on panic() Date: Mon, 18 Jun 2018 10:14:22 +0200 Message-Id: <20180618080620.133552872@linuxfoundation.org> In-Reply-To: <20180618080608.851973560@linuxfoundation.org> References: <20180618080608.851973560@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Russell King [ Upstream commit 2d7b3c64431245c95b05a441669c074da10db943 ] When a panic() occurs, the kexec code uses smp_send_stop() to stop the other CPUs, but this results in the CPU register state not being saved, and gdb is unable to inspect the state of other CPUs. Commit 0ee59413c967 ("x86/panic: replace smp_send_stop() with kdump friendly version in panic path") addressed the issue on x86, but ignored other architectures. Address the issue on ARM by splitting out the crash stop implementation to crash_smp_send_stop() and adding the necessary protection. Signed-off-by: Russell King Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/arm/kernel/machine_kexec.c | 34 ++++++++++++++++++++++------------ 1 file changed, 22 insertions(+), 12 deletions(-) --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -95,6 +95,27 @@ void machine_crash_nonpanic_core(void *u cpu_relax(); } +void crash_smp_send_stop(void) +{ + static int cpus_stopped; + unsigned long msecs; + + if (cpus_stopped) + return; + + atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); + smp_call_function(machine_crash_nonpanic_core, NULL, false); + msecs = 1000; /* Wait at most a second for the other cpus to stop */ + while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { + mdelay(1); + msecs--; + } + if (atomic_read(&waiting_for_crash_ipi) > 0) + pr_warn("Non-crashing CPUs did not react to IPI\n"); + + cpus_stopped = 1; +} + static void machine_kexec_mask_interrupts(void) { unsigned int i; @@ -120,19 +141,8 @@ static void machine_kexec_mask_interrupt void machine_crash_shutdown(struct pt_regs *regs) { - unsigned long msecs; - local_irq_disable(); - - atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); - smp_call_function(machine_crash_nonpanic_core, NULL, false); - msecs = 1000; /* Wait at most a second for the other cpus to stop */ - while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { - mdelay(1); - msecs--; - } - if (atomic_read(&waiting_for_crash_ipi) > 0) - pr_warn("Non-crashing CPUs did not react to IPI\n"); + crash_smp_send_stop(); crash_save_cpu(regs, smp_processor_id()); machine_kexec_mask_interrupts();