Added to 026test008 Patch from OpenVZ team <devel@openvz.org> 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. Taken back from -mm tree. Signed-off-by: Kirill Korotaev <dev@sw.ru> Signed-off-by: Pavel Emelianov <xemul@sw.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> diff -puN arch/i386/kernel/nmi.c~nmi-lockup-and-altsysrq-p-dumping-cal ltraces-on-_all_-cpus arch/i386/kernel/nmi.c --- devel/arch/i386/kernel/nmi.c~nmi-lockup-and-altsysrq-p-dumpi ng-calltraces-on-_all_-cpus 2006-03-18 00:55:33.000000000 -0800 +++ devel-akpm/arch/i386/kernel/nmi.c 2006-03-18 01:11:52.000000000 -0800 @@ -523,6 +523,21 @@ 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) { diff -puN arch/i386/kernel/smp.c~nmi-lockup-and-altsysrq-p-dumping-cal ltraces-on-_all_-cpus arch/i386/kernel/smp.c --- devel/arch/i386/kernel/smp.c~nmi-lockup-and-altsysrq-p-dumpi ng-calltraces-on-_all_-cpus 2006-03-18 00:55:33.000000000 -0800 +++ devel-akpm/arch/i386/kernel/smp.c 2006-03-18 00:55:33.000000000 -0800 @@ -21,6 +21,7 @@ #include <linux/cpu.h> #include <linux/module.h> +#include <asm/nmi.h> #include <asm/mtrr.h> #include <asm/tlbflush.h> #include <mach_apic.h> @@ -562,6 +563,89 @@ int smp_call_function (void (*func) (voi } EXPORT_SYMBOL(smp_call_function); +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) { /* diff -puN arch/i386/kernel/traps.c~nmi-lockup-and-altsysrq-p-dumping-c alltraces-on-_all_-cpus arch/i386/kernel/traps.c --- devel/arch/i386/kernel/traps.c~nmi-lockup-and-altsysrq-p-dum ping-calltraces-on-_all_-cpus 2006-03-18 00:55:33.000000000 -0800 +++ devel-akpm/arch/i386/kernel/traps.c 2006-03-18 01:11:52.000000000 -0800 @@ -689,6 +689,8 @@ 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(KERN_EMERG "console shuts up ...\n"); console_silent(); spin_unlock(&nmi_print_lock); @@ -705,6 +707,14 @@ void die_nmi (struct pt_regs *regs, cons do_exit(SIGSEGV); } +static int dummy_nmi_callback(struct pt_regs * regs, int cpu) +{ + return 0; +} + +static nmi_callback_t nmi_callback = dummy_nmi_callback; +static nmi_callback_t nmi_ipi_callback = dummy_nmi_callback; + static void default_do_nmi(struct pt_regs * regs) { unsigned char reason = 0; @@ -727,6 +737,9 @@ static void default_do_nmi(struct pt_reg return; } #endif + if (nmi_ipi_callback != dummy_nmi_callback) + return; + unknown_nmi_error(reason, regs); return; } @@ -743,13 +756,6 @@ static void default_do_nmi(struct pt_reg reassert_nmi(); } -static int dummy_nmi_callback(struct pt_regs * regs, int cpu) -{ - return 0; -} - -static nmi_callback_t nmi_callback = dummy_nmi_callback; - fastcall void do_nmi(struct pt_regs * regs, long error_code) { int cpu; @@ -763,9 +769,20 @@ fastcall void do_nmi(struct pt_regs * re if (!rcu_dereference(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) { rcu_assign_pointer(nmi_callback, callback); diff -puN drivers/char/sysrq.c~nmi-lockup-and-altsysrq-p-dumping-callt races-on-_all_-cpus drivers/char/sysrq.c --- devel/drivers/char/sysrq.c~nmi-lockup-and-altsysrq-p-dumping -calltraces-on-_all_-cpus 2006-03-18 00:55:33.000000000 -0800 +++ devel-akpm/drivers/char/sysrq.c 2006-03-18 00:55:33.000000000 -0800 @@ -183,8 +183,13 @@ static struct sysrq_key_op sysrq_showloc 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, diff -puN include/asm-i386/nmi.h~nmi-lockup-and-altsysrq-p-dumping-cal ltraces-on-_all_-cpus include/asm-i386/nmi.h --- devel/include/asm-i386/nmi.h~nmi-lockup-and-altsysrq-p-dumpi ng-calltraces-on-_all_-cpus 2006-03-18 00:55:33.000000000 -0800 +++ devel-akpm/include/asm-i386/nmi.h 2006-03-18 00:55:33.000000000 -0800 @@ -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 */ diff -puN include/linux/sched.h~nmi-lockup-and-altsysrq-p-dumping-call traces-on-_all_-cpus include/linux/sched.h --- devel/include/linux/sched.h~nmi-lockup-and-altsysrq-p-dumpin g-calltraces-on-_all_-cpus 2006-03-18 00:55:33.000000000 -0800 +++ devel-akpm/include/linux/sched.h 2006-03-18 00:55:33.000000000 -0800 @@ -193,6 +193,7 @@ 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 diff -puN include/linux/smp.h~nmi-lockup-and-altsysrq-p-dumping-calltr aces-on-_all_-cpus include/linux/smp.h --- devel/include/linux/smp.h~nmi-lockup-and-altsysrq-p-dumping- calltraces-on-_all_-cpus 2006-03-18 00:55:33.000000000 -0800 +++ devel-akpm/include/linux/smp.h 2006-03-18 01:12:41.000000000 -0800 @@ -10,6 +10,9 @@ extern void cpu_idle(void); +struct pt_regs; +typedef void (*smp_nmi_function)(struct pt_regs *regs, void *info); + #ifdef CONFIG_SMP #include <linux/preempt.h> @@ -49,6 +52,8 @@ extern int __cpu_up(unsigned int cpunum) */ extern void smp_cpus_done(unsigned int max_cpus); +extern int smp_nmi_call_function(smp_nmi_function func, void *info, int wait); + /* * Call a function on all other processors */ @@ -94,6 +99,12 @@ static inline void smp_send_reschedule(i #define num_booting_cpus() 1 #define smp_prepare_boot_cpu() do {} while (0) +static inline int smp_nmi_call_function(smp_nmi_function func, + void *info, int wait) +{ + return 0; +} + #endif /* !SMP */ /*