Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753923Ab1C2Qfz (ORCPT ); Tue, 29 Mar 2011 12:35:55 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:57451 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753890Ab1C2Qfy (ORCPT ); Tue, 29 Mar 2011 12:35:54 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.5.1 From: Takao Indoh To: linux-kernel@vger.kernel.org, kexec@lists.infradead.org Cc: Milton Miller , Jens Axboe , "Paul E. McKenney" , Ingo Molnar , Vivek Goyal , WANG Cong , Peter Zijlstra Subject: [PATCH v2] generic-ipi: Initialize call_single_queue before enabling interrupt Date: Tue, 29 Mar 2011 12:35:04 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: HidemaruMail 5.38 (WinNT,501) Message-Id: X-Antivirus: avast! (VPS 110329-0, 2011/03/29), Outbound message X-Antivirus-Status: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4160 Lines: 119 Hi all, This patch renames init_call_single_data() to call_function_init() and calls it in start_kernel() so that call_single_queue can be initialized before enabling interrupt. There is a problem that kdump(2nd kernel) sometimes hangs up due to pending IPI from 1st kernel. Kernel panic occurs because IPI comes before call_single_queue is initialized. The details are as follows. (1) 2nd kernel boot up (2) A pending IPI from 1st kernel comes when irqs are first enabled in start_kernel(). (3) Kernel tries to handle the interrupt, but call_single_queue is not initialized yet at this point. As a result, in the generic_smp_call_function_single_interrupt(), NULL pointer dereference occurs when list_replace_init() tries to access &q->list.next. Therefore this patch changes the name of init_call_single_data() to call_function_init() and calls it before local_irq_enable() in start_kernel(). v2: - Rename init_call_single_data() to call_function_init() and calls it in start_kernel() - Change insert position in start_kernel(). - Adjust for CONFIG_SMP/CONFIG_USE_GENERIC_SMP_HELPERS options - Rebased to Linus's latest tree v1: https://lkml.org/lkml/2011/3/25/317 - Divide init_call_single_data() into two functions, o init_call_single_data: initialize call_single_queue o init_hotplug_cfd: initialize hotplug_cfd_notifier And call init_call_single_data before local_irq_enable() in start_kernel(). v0: https://lkml.org/lkml/2011/3/23/417 - In generic_smp_call_function_single_interrupt(), check if call_single_queue was initialized or not, and just return if not initialized. Signed-off-by: Takao Indoh --- include/linux/smp.h | 5 ++++- init/main.c | 1 + kernel/smp.c | 5 +---- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/include/linux/smp.h b/include/linux/smp.h index 74243c8..4fb3eac 100644 --- a/include/linux/smp.h +++ b/include/linux/smp.h @@ -85,12 +85,15 @@ int smp_call_function_any(const struct cpumask *mask, * Generic and arch helpers */ #ifdef CONFIG_USE_GENERIC_SMP_HELPERS +void __init call_function_init(void); void generic_smp_call_function_single_interrupt(void); void generic_smp_call_function_interrupt(void); void ipi_call_lock(void); void ipi_call_unlock(void); void ipi_call_lock_irq(void); void ipi_call_unlock_irq(void); +#else +static inline void call_function_init(void) { } #endif /* @@ -144,7 +147,7 @@ static inline void smp_send_reschedule(int cpu) { } #define smp_prepare_boot_cpu() do {} while (0) #define smp_call_function_many(mask, func, info, wait) \ (up_smp_call_function(func, info)) -static inline void init_call_single_data(void) { } +static inline void call_function_init(void) { } static inline int smp_call_function_any(const struct cpumask *mask, smp_call_func_t func, diff --git a/init/main.c b/init/main.c index 4a9479e..12821d1 100644 --- a/init/main.c +++ b/init/main.c @@ -539,6 +539,7 @@ asmlinkage void __init start_kernel(void) timekeeping_init(); time_init(); profile_init(); + call_function_init(); if (!irqs_disabled()) printk(KERN_CRIT "start_kernel(): bug: interrupts were " "enabled early\n"); diff --git a/kernel/smp.c b/kernel/smp.c index 73a1951..fb67dfa 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -74,7 +74,7 @@ static struct notifier_block __cpuinitdata hotplug_cfd_notifier = { .notifier_call = hotplug_cfd, }; -static int __cpuinit init_call_single_data(void) +void __init call_function_init(void) { void *cpu = (void *)(long)smp_processor_id(); int i; @@ -88,10 +88,7 @@ static int __cpuinit init_call_single_data(void) hotplug_cfd(&hotplug_cfd_notifier, CPU_UP_PREPARE, cpu); register_cpu_notifier(&hotplug_cfd_notifier); - - return 0; } -early_initcall(init_call_single_data); /* * csd_lock/csd_unlock used to serialize access to per-cpu csd resources -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/