Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261980AbVEKP6O (ORCPT ); Wed, 11 May 2005 11:58:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261981AbVEKP6O (ORCPT ); Wed, 11 May 2005 11:58:14 -0400 Received: from mailhub.sw.ru ([195.214.233.200]:38681 "EHLO relay.sw.ru") by vger.kernel.org with ESMTP id S261980AbVEKP5Y (ORCPT ); Wed, 11 May 2005 11:57:24 -0400 Message-ID: <42822B5F.8040901@sw.ru> Date: Wed, 11 May 2005 19:57:19 +0400 From: Kirill Korotaev User-Agent: Mozilla/5.0 (X11; U; Linux i686; ru-RU; rv:1.2.1) Gecko/20030426 X-Accept-Language: ru-ru, en MIME-Version: 1.0 To: Andrew Morton , Linus Torvalds , linux-kernel@vger.kernel.org Subject: [PATCH] NMI lockup and AltSysRq-P dumping calltraces on _all_ cpus via NMI IPI Content-Type: multipart/mixed; boundary="------------000901000101090109080902" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7773 Lines: 262 This is a multi-part message in MIME format. --------------000901000101090109080902 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit against 2.6.12-rc4 This patch adds dumping of calltraces on _all_ CPUs on AltSysRq-P and NMI LOCKUP. It does this via sending NMI IPI interrupts to the cpus. I saw the same patch in RedHat kernels, here goes our own version of the patch, not sure it will be accepted, but I think it can be used by some people at least for debugging lockups etc. Signed-Off-By: Kirill Korotaev Signed-Off-By: Pavel Emelianov Kirill --------------000901000101090109080902 Content-Type: text/plain; name="diff-mainstream-ipi-calltraces-20050412" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="diff-mainstream-ipi-calltraces-20050412" --- ./arch/i386/kernel/nmi.c.ipicalltraces 2005-05-10 16:09:58.000000000 +0400 +++ ./arch/i386/kernel/nmi.c 2005-05-10 18:20:00.000000000 +0400 @@ -476,6 +476,21 @@ void touch_nmi_watchdog (void) extern void die_nmi(struct pt_regs *, const char *msg); +static spinlock_t show_regs_lock = SPIN_LOCK_UNLOCKED; + +void smp_show_regs(struct pt_regs *regs, void *info) +{ + if (regs == NULL) + return; + + bust_spinlocks(1); + spin_lock(&show_regs_lock); + printk("----------- IPI show regs -----------"); + show_regs(regs); + spin_unlock(&show_regs_lock); + bust_spinlocks(0); +} + void nmi_watchdog_tick (struct pt_regs * regs) { --- ./arch/i386/kernel/smp.c.ipicalltraces 2005-05-10 16:09:58.000000000 +0400 +++ ./arch/i386/kernel/smp.c 2005-05-10 18:28:08.000000000 +0400 @@ -20,6 +20,7 @@ #include #include +#include #include #include #include @@ -548,6 +549,89 @@ int smp_call_function (void (*func) (voi return 0; } +static spinlock_t nmi_call_lock = SPIN_LOCK_UNLOCKED; +static struct nmi_call_data_struct { + smp_nmi_function func; + void *info; + atomic_t started; + atomic_t finished; + cpumask_t cpus_called; + int wait; +} *nmi_call_data; + +static int smp_nmi_callback(struct pt_regs * regs, int cpu) +{ + smp_nmi_function func; + void *info; + int wait; + + func = nmi_call_data->func; + info = nmi_call_data->info; + wait = nmi_call_data->wait; + ack_APIC_irq(); + /* prevent from calling func() multiple times */ + if (cpu_test_and_set(cpu, nmi_call_data->cpus_called)) + return 0; + /* + * notify initiating CPU that I've grabbed the data and am + * about to execute the function + */ + mb(); + atomic_inc(&nmi_call_data->started); + /* at this point the nmi_call_data structure is out of scope */ + irq_enter(); + func(regs, info); + irq_exit(); + if (wait) + atomic_inc(&nmi_call_data->finished); + + return 0; +} + +/* + * This function tries to call func(regs, info) on each cpu. + * Func must be fast and non-blocking. + * May be called with disabled interrupts and from any context. + */ +int smp_nmi_call_function(smp_nmi_function func, void *info, int wait) +{ + struct nmi_call_data_struct data; + int cpus; + + cpus = num_online_cpus() - 1; + if (!cpus) + return 0; + + data.func = func; + data.info = info; + data.wait = wait; + atomic_set(&data.started, 0); + atomic_set(&data.finished, 0); + cpus_clear(data.cpus_called); + /* prevent this cpu from calling func if NMI happens */ + cpu_set(smp_processor_id(), data.cpus_called); + + if (!spin_trylock(&nmi_call_lock)) + return -1; + + nmi_call_data = &data; + set_nmi_ipi_callback(smp_nmi_callback); + mb(); + + /* Send a message to all other CPUs and wait for them to respond */ + send_IPI_allbutself(APIC_DM_NMI); + while (atomic_read(&data.started) != cpus) + barrier(); + + unset_nmi_ipi_callback(); + if (wait) + while (atomic_read(&data.finished) != cpus) + barrier(); + spin_unlock(&nmi_call_lock); + + return 0; +} + static void stop_this_cpu (void * dummy) { /* --- ./arch/i386/kernel/traps.c.ipicalltraces 2005-05-10 16:09:58.000000000 +0400 +++ ./arch/i386/kernel/traps.c 2005-05-10 18:27:04.000000000 +0400 @@ -565,6 +565,8 @@ void die_nmi (struct pt_regs *regs, cons printk(" on CPU%d, eip %08lx, registers:\n", smp_processor_id(), regs->eip); show_registers(regs); + smp_nmi_call_function(smp_show_regs, NULL, 1); + bust_spinlocks(1); printk("console shuts up ...\n"); console_silent(); spin_unlock(&nmi_print_lock); @@ -616,6 +618,7 @@ static int dummy_nmi_callback(struct pt_ } static nmi_callback_t nmi_callback = dummy_nmi_callback; +static nmi_callback_t nmi_ipi_callback = dummy_nmi_callback; fastcall void do_nmi(struct pt_regs * regs, long error_code) { @@ -629,9 +632,20 @@ fastcall void do_nmi(struct pt_regs * re if (!nmi_callback(regs, cpu)) default_do_nmi(regs); + nmi_ipi_callback(regs, cpu); nmi_exit(); } +void set_nmi_ipi_callback(nmi_callback_t callback) +{ + nmi_ipi_callback = callback; +} + +void unset_nmi_ipi_callback(void) +{ + nmi_ipi_callback = dummy_nmi_callback; +} + void set_nmi_callback(nmi_callback_t callback) { nmi_callback = callback; --- ./drivers/char/sysrq.c.ipicalltraces 2005-05-10 16:10:05.000000000 +0400 +++ ./drivers/char/sysrq.c 2005-05-10 18:20:00.000000000 +0400 @@ -143,8 +143,13 @@ static struct sysrq_key_op sysrq_mountro static void sysrq_handle_showregs(int key, struct pt_regs *pt_regs, struct tty_struct *tty) { + bust_spinlocks(1); if (pt_regs) show_regs(pt_regs); + bust_spinlocks(0); +#ifdef __i386__ + smp_nmi_call_function(smp_show_regs, NULL, 0); +#endif } static struct sysrq_key_op sysrq_showregs_op = { .handler = sysrq_handle_showregs, --- ./include/asm-i386/nmi.h.ipicalltraces 2005-03-02 10:37:54.000000000 +0300 +++ ./include/asm-i386/nmi.h 2005-05-10 18:20:00.000000000 +0400 @@ -17,6 +17,7 @@ typedef int (*nmi_callback_t)(struct pt_ * set. Return 1 if the NMI was handled. */ void set_nmi_callback(nmi_callback_t callback); +void set_nmi_ipi_callback(nmi_callback_t callback); /** * unset_nmi_callback @@ -24,5 +25,6 @@ void set_nmi_callback(nmi_callback_t cal * Remove the handler previously set. */ void unset_nmi_callback(void); +void unset_nmi_ipi_callback(void); #endif /* ASM_NMI_H */ --- ./include/linux/sched.h.ipicalltraces 2005-05-10 16:10:39.000000000 +0400 +++ ./include/linux/sched.h 2005-05-10 18:20:00.000000000 +0400 @@ -160,6 +160,7 @@ extern cpumask_t nohz_cpu_mask; extern void show_state(void); extern void show_regs(struct pt_regs *); +extern void smp_show_regs(struct pt_regs *, void *); /* * TASK is a pointer to the task whose backtrace we want to see (or NULL for current --- ./include/linux/smp.h.ipicalltraces 2005-05-10 16:10:39.000000000 +0400 +++ ./include/linux/smp.h 2005-05-10 18:20:00.000000000 +0400 @@ -56,6 +56,9 @@ extern void smp_cpus_done(unsigned int m extern int smp_call_function (void (*func) (void *info), void *info, int retry, int wait); +typedef void (*smp_nmi_function)(struct pt_regs *regs, void *info); +extern int smp_nmi_call_function(smp_nmi_function func, void *info, int wait); + /* * Call a function on all processors */ @@ -98,6 +101,7 @@ void smp_prepare_boot_cpu(void); #endif #define hard_smp_processor_id() 0 #define smp_call_function(func,info,retry,wait) ({ 0; }) +#define smp_nmi_call_function(func, info, wait) ({ 0; }) #define on_each_cpu(func,info,retry,wait) ({ func(info); 0; }) static inline void smp_send_reschedule(int cpu) { } #define num_booting_cpus() 1 --------------000901000101090109080902-- - 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/