From 097114aa6eb2aa206c8cf136de77ebffe424234c Mon Sep 17 00:00:00 2001 From: Dave Young Date: Sat, 27 Jan 2018 12:11:29 +0800 Subject: [PATCH 1/3] print kdump kernel loaded status in stack dump It is useful to print kdump kernel loaded status in dump_stack() especially when panic happens so that we can differenciate kdump kernel early hang and a normal panic in a bug report. Link: http://lkml.kernel.org/r/20180127041129.GA29016@dhcp-128-65.nay.redhat.com To: Steven Rostedt To: Andi Kleen To: kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org Cc: kexec@lists.infradead.org Signed-off-by: Dave Young Reviewed-by: Sergey Senozhatsky Reviewed-by: Simon Horman Signed-off-by: Petr Mladek --- kernel/printk/printk.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index db4b9b8929eb..fa3de5f10e0e 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -48,6 +48,7 @@ #include #include #include +#include #include #include @@ -3287,9 +3288,11 @@ void __init dump_stack_set_arch_desc(const char *fmt, ...) */ void dump_stack_print_info(const char *log_lvl) { - printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n", + printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s\n", log_lvl, raw_smp_processor_id(), current->pid, current->comm, - print_tainted(), init_utsname()->release, + kexec_crash_loaded() ? "Kdump: loaded " : "", + print_tainted(), + init_utsname()->release, (int)strcspn(init_utsname()->version, " "), init_utsname()->version); From e36df28f532f882965404d58e240f2e058b61f45 Mon Sep 17 00:00:00 2001 From: Dave Young Date: Tue, 13 Feb 2018 15:28:34 +0800 Subject: [PATCH 2/3] printk: move dump stack related code to lib/dump_stack.c dump_stack related stuff should belong to lib/dump_stack.c thus move them there. Also conditionally compile lib/dump_stack.c since dump_stack code does not make sense if printk is disabled. Link: http://lkml.kernel.org/r/20180213072834.GA24784@dhcp-128-65.nay.redhat.com To: Steven Rostedt Cc: linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org Cc: Andi Kleen Signed-off-by: Dave Young Suggested-by: Steven Rostedt Suggested-by: Sergey Senozhatsky Reviewed-by: Sergey Senozhatsky Signed-off-by: Petr Mladek --- include/linux/printk.h | 7 +++-- kernel/printk/printk.c | 60 ------------------------------------------ lib/Makefile | 3 ++- lib/dump_stack.c | 60 ++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 67 insertions(+), 63 deletions(-) diff --git a/include/linux/printk.h b/include/linux/printk.h index e9b603ee9953..6d7e800affd8 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -201,6 +201,7 @@ void __init setup_log_buf(int early); __printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...); void dump_stack_print_info(const char *log_lvl); void show_regs_print_info(const char *log_lvl); +extern asmlinkage void dump_stack(void) __cold; extern void printk_safe_init(void); extern void printk_safe_flush(void); extern void printk_safe_flush_on_panic(void); @@ -264,6 +265,10 @@ static inline void show_regs_print_info(const char *log_lvl) { } +static inline asmlinkage void dump_stack(void) +{ +} + static inline void printk_safe_init(void) { } @@ -279,8 +284,6 @@ static inline void printk_safe_flush_on_panic(void) extern int kptr_restrict; -extern asmlinkage void dump_stack(void) __cold; - #ifndef pr_fmt #define pr_fmt(fmt) fmt #endif diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index fa3de5f10e0e..dc663f288463 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -42,13 +42,11 @@ #include #include #include -#include #include #include #include #include #include -#include #include #include @@ -3257,62 +3255,4 @@ void kmsg_dump_rewind(struct kmsg_dumper *dumper) } EXPORT_SYMBOL_GPL(kmsg_dump_rewind); -static char dump_stack_arch_desc_str[128]; - -/** - * dump_stack_set_arch_desc - set arch-specific str to show with task dumps - * @fmt: printf-style format string - * @...: arguments for the format string - * - * The configured string will be printed right after utsname during task - * dumps. Usually used to add arch-specific system identifiers. If an - * arch wants to make use of such an ID string, it should initialize this - * as soon as possible during boot. - */ -void __init dump_stack_set_arch_desc(const char *fmt, ...) -{ - va_list args; - - va_start(args, fmt); - vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), - fmt, args); - va_end(args); -} - -/** - * dump_stack_print_info - print generic debug info for dump_stack() - * @log_lvl: log level - * - * Arch-specific dump_stack() implementations can use this function to - * print out the same debug information as the generic dump_stack(). - */ -void dump_stack_print_info(const char *log_lvl) -{ - printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s\n", - log_lvl, raw_smp_processor_id(), current->pid, current->comm, - kexec_crash_loaded() ? "Kdump: loaded " : "", - print_tainted(), - init_utsname()->release, - (int)strcspn(init_utsname()->version, " "), - init_utsname()->version); - - if (dump_stack_arch_desc_str[0] != '\0') - printk("%sHardware name: %s\n", - log_lvl, dump_stack_arch_desc_str); - - print_worker_info(log_lvl, current); -} - -/** - * show_regs_print_info - print generic debug info for show_regs() - * @log_lvl: log level - * - * show_regs() implementations can use this function to print out generic - * debug information. - */ -void show_regs_print_info(const char *log_lvl) -{ - dump_stack_print_info(log_lvl); -} - #endif diff --git a/lib/Makefile b/lib/Makefile index 7adb066692b3..6ae3bd481379 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -18,7 +18,7 @@ KCOV_INSTRUMENT_debugobjects.o := n KCOV_INSTRUMENT_dynamic_debug.o := n lib-y := ctype.o string.o vsprintf.o cmdline.o \ - rbtree.o radix-tree.o dump_stack.o timerqueue.o\ + rbtree.o radix-tree.o timerqueue.o\ idr.o int_sqrt.o extable.o \ sha1.o chacha20.o irq_regs.o argv_split.o \ flex_proportions.o ratelimit.o show_mem.o \ @@ -26,6 +26,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ earlycpio.o seq_buf.o siphash.o \ nmi_backtrace.o nodemask.o win_minmax.o +lib-$(CONFIG_PRINTK) += dump_stack.o lib-$(CONFIG_MMU) += ioremap.o lib-$(CONFIG_SMP) += cpumask.o lib-$(CONFIG_DMA_DIRECT_OPS) += dma-direct.o diff --git a/lib/dump_stack.c b/lib/dump_stack.c index c5edbedd364d..5cff72f18c4a 100644 --- a/lib/dump_stack.c +++ b/lib/dump_stack.c @@ -10,6 +10,66 @@ #include #include #include +#include +#include + +static char dump_stack_arch_desc_str[128]; + +/** + * dump_stack_set_arch_desc - set arch-specific str to show with task dumps + * @fmt: printf-style format string + * @...: arguments for the format string + * + * The configured string will be printed right after utsname during task + * dumps. Usually used to add arch-specific system identifiers. If an + * arch wants to make use of such an ID string, it should initialize this + * as soon as possible during boot. + */ +void __init dump_stack_set_arch_desc(const char *fmt, ...) +{ + va_list args; + + va_start(args, fmt); + vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), + fmt, args); + va_end(args); +} + +/** + * dump_stack_print_info - print generic debug info for dump_stack() + * @log_lvl: log level + * + * Arch-specific dump_stack() implementations can use this function to + * print out the same debug information as the generic dump_stack(). + */ +void dump_stack_print_info(const char *log_lvl) +{ + printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s\n", + log_lvl, raw_smp_processor_id(), current->pid, current->comm, + kexec_crash_loaded() ? "Kdump: loaded " : "", + print_tainted(), + init_utsname()->release, + (int)strcspn(init_utsname()->version, " "), + init_utsname()->version); + + if (dump_stack_arch_desc_str[0] != '\0') + printk("%sHardware name: %s\n", + log_lvl, dump_stack_arch_desc_str); + + print_worker_info(log_lvl, current); +} + +/** + * show_regs_print_info - print generic debug info for show_regs() + * @log_lvl: log level + * + * show_regs() implementations can use this function to print out generic + * debug information. + */ +void show_regs_print_info(const char *log_lvl) +{ + dump_stack_print_info(log_lvl); +} static void __dump_stack(void) { From 47319f7186b8746521b0ee674054b29d7b35578b Mon Sep 17 00:00:00 2001 From: Tomeu Vizoso Date: Thu, 22 Mar 2018 14:58:33 +0100 Subject: [PATCH 3/3] printk: change message to pr_info To allow userspace to prevent this message from appearing in the console by changing the log priority. This matches other informative messages that the power subsystem emits when the system changes power states. Link: http://lkml.kernel.org/r/20180322135833.16602-1-tomeu.vizoso@collabora.com To: linux-kernel@vger.kernel.org Cc: kernel@collabora.com Cc: Steven Rostedt Signed-off-by: Tomeu Vizoso Reviewed-by: Sergey Senozhatsky Signed-off-by: Petr Mladek --- kernel/printk/printk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index dc663f288463..333f58eac420 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2161,7 +2161,7 @@ void suspend_console(void) { if (!console_suspend_enabled) return; - printk("Suspending console(s) (use no_console_suspend to debug)\n"); + pr_info("Suspending console(s) (use no_console_suspend to debug)\n"); console_lock(); console_suspended = 1; up_console_sem();