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+ torvalds#9 0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48 ffffffff8108f50f ffffffff82228240 0000000000000040 ffffffff8234a03c 0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58 Call Trace: [<ffffffff81c614dc>] dump_stack+0x19/0x1b [<ffffffff8108f50f>] warn_slowpath_common+0x7f/0xc0 [<ffffffff8108f56a>] warn_slowpath_null+0x1a/0x20 [<ffffffff8234a071>] 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 <[email protected]> Acked-by: David S. Miller <[email protected]> Acked-by: Vineet Gupta <[email protected]> Acked-by: Jesper Nilsson <[email protected]> Acked-by: Vineet Gupta <[email protected]> Acked-by: Martin Schwidefsky <[email protected]> [s390 bits] Cc: Heiko Carstens <[email protected]> Cc: Mike Frysinger <[email protected]> Cc: Fengguang Wu <[email protected]> Cc: Bjorn Helgaas <[email protected]> Cc: Sam Ravnborg <[email protected]> Acked-by: Richard Kuo <[email protected]> [hexagon bits] Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
gunnarahlberg · May 1, 2013 · 196779b · 196779b
1 parent 89e3f23
commit 196779b
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Showing 33 changed files with 32 additions and 262 deletions.
diff --git 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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -146,13 +146,6 @@ 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 *))
 {

diff --git 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
@@ -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
@@ -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
@@ -95,14 +95,6 @@ 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)
 {

diff --git 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
@@ -991,18 +991,6 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 	show_trace(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

diff --git 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
@@ -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
@@ -206,19 +206,6 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	show_stacktrace(task, &regs);
 }
 
-/*
- * The architecture-independent dump_stack generator
- */
-void dump_stack(void)
-{
-	struct pt_regs regs;
-
-	prepare_frametrace(&regs);
-	show_backtrace(current, &regs);
-}
-
-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
@@ -293,17 +293,6 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	show_trace(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
  */

diff --git 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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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];