From 196779b9b4ce1922afabdc20d0270720603bd46c Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 30 Apr 2013 15:27:12 -0700 Subject: dump_stack: consolidate dump_stack() implementations and unify their behaviors Both dump_stack() and show_stack() are currently implemented by each architecture. show_stack(NULL, NULL) dumps the backtrace for the current task as does dump_stack(). On some archs, dump_stack() prints extra information - pid, utsname and so on - in addition to the backtrace while the two are identical on other archs. The usages in arch-independent code of the two functions indicate show_stack(NULL, NULL) should print out bare backtrace while dump_stack() is used for debugging purposes when something went wrong, so it does make sense to print additional information on the task which triggered dump_stack(). There's no reason to require archs to implement two separate but mostly identical functions. It leads to unnecessary subtle information. This patch expands the dummy fallback dump_stack() implementation in lib/dump_stack.c such that it prints out debug information (taken from x86) and invokes show_stack(NULL, NULL) and drops arch-specific dump_stack() implementations in all archs except blackfin. Blackfin's dump_stack() does something wonky that I don't understand. Debug information can be printed separately by calling dump_stack_print_info() so that arch-specific dump_stack() implementation can still emit the same debug information. This is used in blackfin. This patch brings the following behavior changes. * On some archs, an extra level in backtrace for show_stack() could be printed. This is because the top frame was determined in dump_stack() on those archs while generic dump_stack() can't do that reliably. It can be compensated by inlining dump_stack() but not sure whether that'd be necessary. * Most archs didn't use to print debug info on dump_stack(). They do now. An example WARN dump follows. WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505() Hardware name: empty Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #9 0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48 ffffffff8108f50f ffffffff82228240 0000000000000040 ffffffff8234a03c 0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58 Call Trace: [] dump_stack+0x19/0x1b [] warn_slowpath_common+0x7f/0xc0 [] warn_slowpath_null+0x1a/0x20 [] init_workqueues+0x35/0x505 ... v2: CPU number added to the generic debug info as requested by s390 folks and dropped the s390 specific dump_stack(). This loses %ksp from the debug message which the maintainers think isn't important enough to keep the s390-specific dump_stack() implementation. dump_stack_print_info() is moved to kernel/printk.c from lib/dump_stack.c. Because linkage is per objecct file, dump_stack_print_info() living in the same lib file as generic dump_stack() means that archs which implement custom dump_stack() - at this point, only blackfin - can't use dump_stack_print_info() as that will bring in the generic version of dump_stack() too. v1 The v1 patch broke build on blackfin due to this issue. The build breakage was reported by Fengguang Wu. Signed-off-by: Tejun Heo Acked-by: David S. Miller Acked-by: Vineet Gupta Acked-by: Jesper Nilsson Acked-by: Vineet Gupta Acked-by: Martin Schwidefsky [s390 bits] Cc: Heiko Carstens Cc: Mike Frysinger Cc: Fengguang Wu Cc: Bjorn Helgaas Cc: Sam Ravnborg Acked-by: Richard Kuo [hexagon bits] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c index 4037461..affccb9 100644 --- a/arch/alpha/kernel/traps.c +++ b/arch/alpha/kernel/traps.c @@ -169,13 +169,6 @@ void show_stack(struct task_struct *task, unsigned long *sp) dik_show_trace(sp); } -void dump_stack(void) -{ - show_stack(NULL, NULL); -} - -EXPORT_SYMBOL(dump_stack); - void die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15) { diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c index a63ff84..ca0207b 100644 --- a/arch/arc/kernel/stacktrace.c +++ b/arch/arc/kernel/stacktrace.c @@ -220,13 +220,6 @@ void show_stack(struct task_struct *tsk, unsigned long *sp) show_stacktrace(tsk, NULL); } -/* Expected by Rest of kernel code */ -void dump_stack(void) -{ - show_stacktrace(NULL, NULL); -} -EXPORT_SYMBOL(dump_stack); - /* Another API expected by schedular, shows up in "ps" as Wait Channel * Ofcourse just returning schedule( ) would be pointless so unwind until * the function is not in schedular code diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 1c08911..18b32e8 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -204,13 +204,6 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) } #endif -void dump_stack(void) -{ - dump_backtrace(NULL, NULL); -} - -EXPORT_SYMBOL(dump_stack); - void show_stack(struct task_struct *tsk, unsigned long *sp) { dump_backtrace(NULL, tsk); diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index b3c5f62..61d7dd2 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -167,13 +167,6 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) } } -void dump_stack(void) -{ - dump_backtrace(NULL, NULL); -} - -EXPORT_SYMBOL(dump_stack); - void show_stack(struct task_struct *tsk, unsigned long *sp) { dump_backtrace(NULL, tsk); diff --git a/arch/avr32/kernel/process.c b/arch/avr32/kernel/process.c index 073c3c2..89a8017 100644 --- a/arch/avr32/kernel/process.c +++ b/arch/avr32/kernel/process.c @@ -204,14 +204,6 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) show_stack_log_lvl(tsk, (unsigned long)stack, NULL, ""); } -void dump_stack(void) -{ - unsigned long stack; - - show_trace_log_lvl(current, &stack, NULL, ""); -} -EXPORT_SYMBOL(dump_stack); - static const char *cpu_modes[] = { "Application", "Supervisor", "Interrupt level 0", "Interrupt level 1", "Interrupt level 2", "Interrupt level 3", "Exception", "NMI" diff --git a/arch/blackfin/kernel/dumpstack.c b/arch/blackfin/kernel/dumpstack.c index 5cfbaa2..95ba6d9 100644 --- a/arch/blackfin/kernel/dumpstack.c +++ b/arch/blackfin/kernel/dumpstack.c @@ -168,6 +168,7 @@ void dump_stack(void) #endif trace_buffer_save(tflags); dump_bfin_trace_buffer(); + dump_stack_print_info(KERN_DEFAULT); show_stack(current, &stack); trace_buffer_restore(tflags); } diff --git a/arch/c6x/kernel/traps.c b/arch/c6x/kernel/traps.c index 1be74e5..d0b96ef 100644 --- a/arch/c6x/kernel/traps.c +++ b/arch/c6x/kernel/traps.c @@ -67,15 +67,6 @@ void show_regs(struct pt_regs *regs) pr_err("A31: %08lx B31: %08lx\n", regs->a31, regs->b31); } -void dump_stack(void) -{ - unsigned long stack; - - show_stack(current, &stack); -} -EXPORT_SYMBOL(dump_stack); - - void die(char *str, struct pt_regs *fp, int nr) { console_verbose(); diff --git a/arch/cris/kernel/traps.c b/arch/cris/kernel/traps.c index a11ad32..0ffda73 100644 --- a/arch/cris/kernel/traps.c +++ b/arch/cris/kernel/traps.c @@ -147,13 +147,6 @@ show_stack(void) #endif void -dump_stack(void) -{ - show_stack(NULL, NULL); -} -EXPORT_SYMBOL(dump_stack); - -void set_nmi_handler(void (*handler)(struct pt_regs *)) { nmi_handler = handler; diff --git a/arch/frv/kernel/traps.c b/arch/frv/kernel/traps.c index 5cfd142..cfcd802 100644 --- a/arch/frv/kernel/traps.c +++ b/arch/frv/kernel/traps.c @@ -466,17 +466,6 @@ asmlinkage void compound_exception(unsigned long esfr1, BUG(); } /* end compound_exception() */ -/*****************************************************************************/ -/* - * The architecture-independent backtrace generator - */ -void dump_stack(void) -{ - show_stack(NULL, NULL); -} - -EXPORT_SYMBOL(dump_stack); - void show_stack(struct task_struct *task, unsigned long *sp) { } diff --git a/arch/h8300/kernel/traps.c b/arch/h8300/kernel/traps.c index 7833aa3..cfe494d 100644 --- a/arch/h8300/kernel/traps.c +++ b/arch/h8300/kernel/traps.c @@ -164,10 +164,3 @@ void show_trace_task(struct task_struct *tsk) { show_stack(tsk,(unsigned long *)tsk->thread.esp0); } - -void dump_stack(void) -{ - show_stack(NULL,NULL); -} - -EXPORT_SYMBOL(dump_stack); diff --git a/arch/hexagon/kernel/traps.c b/arch/hexagon/kernel/traps.c index be5e2dd..cc2171b 100644 --- a/arch/hexagon/kernel/traps.c +++ b/arch/hexagon/kernel/traps.c @@ -191,14 +191,6 @@ void show_stack(struct task_struct *task, unsigned long *fp) do_show_stack(task, fp, 0); } -void dump_stack(void) -{ - unsigned long *fp; - asm("%0 = r30" : "=r" (fp)); - show_stack(current, fp); -} -EXPORT_SYMBOL(dump_stack); - int die(const char *str, struct pt_regs *regs, long err) { static struct { diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c index a26fc64..182bd64 100644 --- a/arch/ia64/kernel/process.c +++ b/arch/ia64/kernel/process.c @@ -96,14 +96,6 @@ show_stack (struct task_struct *task, unsigned long *sp) } void -dump_stack (void) -{ - show_stack(NULL, NULL); -} - -EXPORT_SYMBOL(dump_stack); - -void show_regs (struct pt_regs *regs) { unsigned long ip = regs->cr_iip + ia64_psr(regs)->ri; diff --git a/arch/m32r/kernel/traps.c b/arch/m32r/kernel/traps.c index 9fe3467..a7a424f 100644 --- a/arch/m32r/kernel/traps.c +++ b/arch/m32r/kernel/traps.c @@ -167,15 +167,6 @@ void show_stack(struct task_struct *task, unsigned long *sp) show_trace(task, sp); } -void dump_stack(void) -{ - unsigned long stack; - - show_trace(current, &stack); -} - -EXPORT_SYMBOL(dump_stack); - static void show_registers(struct pt_regs *regs) { int i = 0; diff --git a/arch/m68k/kernel/traps.c b/arch/m68k/kernel/traps.c index f32ab22..88fcd8c 100644 --- a/arch/m68k/kernel/traps.c +++ b/arch/m68k/kernel/traps.c @@ -992,18 +992,6 @@ void show_stack(struct task_struct *task, unsigned long *stack) } /* - * The architecture-independent backtrace generator - */ -void dump_stack(void) -{ - unsigned long stack; - - show_trace(&stack); -} - -EXPORT_SYMBOL(dump_stack); - -/* * The vector number returned in the frame pointer may also contain * the "fs" (Fault Status) bits on ColdFire. These are in the bottom * 2 bits, and upper 2 bits. So we need to mask out the real vector diff --git a/arch/metag/kernel/traps.c b/arch/metag/kernel/traps.c index 8961f24..2ceeaae 100644 --- a/arch/metag/kernel/traps.c +++ b/arch/metag/kernel/traps.c @@ -987,9 +987,3 @@ void show_stack(struct task_struct *tsk, unsigned long *sp) show_trace(tsk, sp, NULL); } - -void dump_stack(void) -{ - show_stack(NULL, NULL); -} -EXPORT_SYMBOL(dump_stack); diff --git a/arch/microblaze/kernel/traps.c b/arch/microblaze/kernel/traps.c index 30e6b50..cb61953 100644 --- a/arch/microblaze/kernel/traps.c +++ b/arch/microblaze/kernel/traps.c @@ -75,9 +75,3 @@ void show_stack(struct task_struct *task, unsigned long *sp) debug_show_held_locks(task); } - -void dump_stack(void) -{ - show_stack(NULL, NULL); -} -EXPORT_SYMBOL(dump_stack); diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index c3abb88..b512b28 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -206,19 +206,6 @@ void show_stack(struct task_struct *task, unsigned long *sp) show_stacktrace(task, ®s); } -/* - * The architecture-independent dump_stack generator - */ -void dump_stack(void) -{ - struct pt_regs regs; - - prepare_frametrace(®s); - show_backtrace(current, ®s); -} - -EXPORT_SYMBOL(dump_stack); - static void show_code(unsigned int __user *pc) { long i; diff --git a/arch/mn10300/kernel/traps.c b/arch/mn10300/kernel/traps.c index b900e5a..a7a987c 100644 --- a/arch/mn10300/kernel/traps.c +++ b/arch/mn10300/kernel/traps.c @@ -294,17 +294,6 @@ void show_stack(struct task_struct *task, unsigned long *sp) } /* - * the architecture-independent dump_stack generator - */ -void dump_stack(void) -{ - unsigned long stack; - - show_stack(current, &stack); -} -EXPORT_SYMBOL(dump_stack); - -/* * dump the register file in the specified exception frame */ void show_registers_only(struct pt_regs *regs) diff --git a/arch/openrisc/kernel/traps.c b/arch/openrisc/kernel/traps.c index 5cce396..3d3f606 100644 --- a/arch/openrisc/kernel/traps.c +++ b/arch/openrisc/kernel/traps.c @@ -105,17 +105,6 @@ void show_trace_task(struct task_struct *tsk) */ } -/* - * The architecture-independent backtrace generator - */ -void dump_stack(void) -{ - unsigned long stack; - - show_stack(current, &stack); -} -EXPORT_SYMBOL(dump_stack); - void show_registers(struct pt_regs *regs) { int i; diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c index aeb8f8f..e64cf5f 100644 --- a/arch/parisc/kernel/traps.c +++ b/arch/parisc/kernel/traps.c @@ -158,14 +158,6 @@ void show_regs(struct pt_regs *regs) } } - -void dump_stack(void) -{ - show_stack(NULL, NULL); -} - -EXPORT_SYMBOL(dump_stack); - static void do_show_stack(struct unwind_frame_info *info) { int i = 1; diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 16e77a8..624d44b 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1362,12 +1362,6 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) } while (count++ < kstack_depth_to_print); } -void dump_stack(void) -{ - show_stack(current, NULL); -} -EXPORT_SYMBOL(dump_stack); - #ifdef CONFIG_PPC64 /* Called with hard IRQs off */ void __ppc64_runlatch_on(void) diff --git a/arch/s390/kernel/dumpstack.c b/arch/s390/kernel/dumpstack.c index 03dce39..2f1f639 100644 --- a/arch/s390/kernel/dumpstack.c +++ b/arch/s390/kernel/dumpstack.c @@ -129,23 +129,6 @@ static void show_last_breaking_event(struct pt_regs *regs) #endif } -/* - * The architecture-independent dump_stack generator - */ -void dump_stack(void) -{ - printk("CPU: %d %s %s %.*s\n", - task_thread_info(current)->cpu, print_tainted(), - init_utsname()->release, - (int)strcspn(init_utsname()->version, " "), - init_utsname()->version); - printk("Process %s (pid: %d, task: %p, ksp: %p)\n", - current->comm, current->pid, current, - (void *) current->thread.ksp); - show_stack(NULL, NULL); -} -EXPORT_SYMBOL(dump_stack); - static inline int mask_bits(struct pt_regs *regs, unsigned long bits) { return (regs->psw.mask & bits) / ((~bits + 1) & bits); diff --git a/arch/score/kernel/traps.c b/arch/score/kernel/traps.c index 0e46fb1..a38f435 100644 --- a/arch/score/kernel/traps.c +++ b/arch/score/kernel/traps.c @@ -149,16 +149,6 @@ static void show_registers(struct pt_regs *regs) printk(KERN_NOTICE "\n"); } -/* - * The architecture-independent dump_stack generator - */ -void dump_stack(void) -{ - show_stack(current_thread_info()->task, - (long *) get_irq_regs()->regs[0]); -} -EXPORT_SYMBOL(dump_stack); - void __die(const char *str, struct pt_regs *regs, const char *file, const char *func, unsigned long line) { diff --git a/arch/sh/kernel/dumpstack.c b/arch/sh/kernel/dumpstack.c index 7617dc4..b959f55 100644 --- a/arch/sh/kernel/dumpstack.c +++ b/arch/sh/kernel/dumpstack.c @@ -158,9 +158,3 @@ void show_stack(struct task_struct *tsk, unsigned long *sp) (unsigned long)task_stack_page(tsk)); show_trace(tsk, sp, NULL); } - -void dump_stack(void) -{ - show_stack(NULL, NULL); -} -EXPORT_SYMBOL(dump_stack); diff --git a/arch/sparc/kernel/process_32.c b/arch/sparc/kernel/process_32.c index 2be4214..dccf5f5 100644 --- a/arch/sparc/kernel/process_32.c +++ b/arch/sparc/kernel/process_32.c @@ -164,13 +164,6 @@ void show_stack(struct task_struct *tsk, unsigned long *_ksp) printk("\n"); } -void dump_stack(void) -{ - show_stack(current, NULL); -} - -EXPORT_SYMBOL(dump_stack); - /* * Note: sparc64 has a pretty intricated thread_saved_pc, check it out. */ diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c index 8d38ca9..b3f833a 100644 --- a/arch/sparc/kernel/traps_64.c +++ b/arch/sparc/kernel/traps_64.c @@ -2350,13 +2350,6 @@ void show_stack(struct task_struct *tsk, unsigned long *_ksp) } while (++count < 16); } -void dump_stack(void) -{ - show_stack(current, NULL); -} - -EXPORT_SYMBOL(dump_stack); - static inline struct reg_window *kernel_stack_up(struct reg_window *rw) { unsigned long fp = rw->ins[6]; diff --git a/arch/um/kernel/sysrq.c b/arch/um/kernel/sysrq.c index e562ff8..7d101a2 100644 --- a/arch/um/kernel/sysrq.c +++ b/arch/um/kernel/sysrq.c @@ -35,18 +35,6 @@ void show_trace(struct task_struct *task, unsigned long * stack) } #endif -/* - * stack dumps generator - this is used by arch-independent code. - * And this is identical to i386 currently. - */ -void dump_stack(void) -{ - unsigned long stack; - - show_trace(current, &stack); -} -EXPORT_SYMBOL(dump_stack); - /*Stolen from arch/i386/kernel/traps.c */ static const int kstack_depth_to_print = 24; diff --git a/arch/unicore32/kernel/traps.c b/arch/unicore32/kernel/traps.c index 0870b68..c54e324 100644 --- a/arch/unicore32/kernel/traps.c +++ b/arch/unicore32/kernel/traps.c @@ -170,12 +170,6 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) c_backtrace(fp, mode); } -void dump_stack(void) -{ - dump_backtrace(NULL, NULL); -} -EXPORT_SYMBOL(dump_stack); - void show_stack(struct task_struct *tsk, unsigned long *sp) { dump_backtrace(NULL, tsk); diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index dd1a7c3..deb6421 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -191,24 +191,6 @@ void show_stack(struct task_struct *task, unsigned long *sp) show_stack_log_lvl(task, NULL, sp, bp, ""); } -/* - * The architecture-independent dump_stack generator - */ -void dump_stack(void) -{ - unsigned long bp; - unsigned long stack; - - bp = stack_frame(current, NULL); - printk("Pid: %d, comm: %.20s %s %s %.*s\n", - current->pid, current->comm, print_tainted(), - init_utsname()->release, - (int)strcspn(init_utsname()->version, " "), - init_utsname()->version); - show_trace(NULL, NULL, &stack, bp); -} -EXPORT_SYMBOL(dump_stack); - static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED; static int die_owner = -1; static unsigned int die_nest_count; diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c index 923db5c..384b7c7 100644 --- a/arch/xtensa/kernel/traps.c +++ b/arch/xtensa/kernel/traps.c @@ -481,14 +481,6 @@ void show_stack(struct task_struct *task, unsigned long *sp) show_trace(task, stack); } -void dump_stack(void) -{ - show_stack(current, NULL); -} - -EXPORT_SYMBOL(dump_stack); - - void show_code(unsigned int *pc) { long i; diff --git a/include/linux/printk.h b/include/linux/printk.h index 4890fe6..7ce1f87 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -145,6 +145,7 @@ extern void wake_up_klogd(void); void log_buf_kexec_setup(void); void __init setup_log_buf(int early); +void dump_stack_print_info(const char *log_lvl); #else static inline __printf(1, 0) int vprintk(const char *s, va_list args) @@ -182,6 +183,10 @@ static inline void log_buf_kexec_setup(void) static inline void setup_log_buf(int early) { } + +static inline void dump_stack_print_info(const char *log_lvl) +{ +} #endif extern void dump_stack(void) __cold; diff --git a/kernel/printk.c b/kernel/printk.c index 376914e..70b4b94 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -43,6 +43,7 @@ #include #include #include +#include #include @@ -2849,4 +2850,21 @@ void kmsg_dump_rewind(struct kmsg_dumper *dumper) raw_spin_unlock_irqrestore(&logbuf_lock, flags); } EXPORT_SYMBOL_GPL(kmsg_dump_rewind); + +/** + * 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\n", + log_lvl, raw_smp_processor_id(), current->pid, current->comm, + print_tainted(), init_utsname()->release, + (int)strcspn(init_utsname()->version, " "), + init_utsname()->version); +} + #endif diff --git a/lib/dump_stack.c b/lib/dump_stack.c index 42f4f55..53bad09 100644 --- a/lib/dump_stack.c +++ b/lib/dump_stack.c @@ -5,11 +5,16 @@ #include #include +#include +/** + * dump_stack - dump the current task information and its stack trace + * + * Architectures can override this implementation by implementing its own. + */ void dump_stack(void) { - printk(KERN_NOTICE - "This architecture does not implement dump_stack()\n"); + dump_stack_print_info(KERN_DEFAULT); + show_stack(NULL, NULL); } - EXPORT_SYMBOL(dump_stack); -- cgit v0.10.2