6 files changed, 83 insertions, 45 deletions

diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 286584667865..78464097470a 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -93,6 +93,7 @@ asmlinkage void spurious_interrupt_bug(void);
 asmlinkage void machine_check(void);
 
 static int kstack_depth_to_print = 24;
+static int call_trace = 1;
 ATOMIC_NOTIFIER_HEAD(i386die_chain);
 
 int register_die_notifier(struct notifier_block *nb)
@@ -171,40 +172,47 @@ static inline unsigned long print_context_stack(struct thread_info *tinfo,
         return ebp;
 }
 
-static asmlinkage void show_trace_unwind(struct unwind_frame_info *info, void *log_lvl)
+static asmlinkage int show_trace_unwind(struct unwind_frame_info *info, void *log_lvl)
 {
+        int n = 0;
         int printed = 0; /* nr of entries already printed on current line */
 
         while (unwind(info) == 0 && UNW_PC(info)) {
+                ++n;
                 printed = print_addr_and_symbol(UNW_PC(info), log_lvl, printed);
                 if (arch_unw_user_mode(info))
                         break;
         }
         if (printed)
                 printk("\n");
+        return n;
 }
 
 static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
                                unsigned long *stack, char *log_lvl)
 {
         unsigned long ebp;
-        struct unwind_frame_info info;
 
         if (!task)
                 task = current;
 
-        if (regs) {
-                if (unwind_init_frame_info(&info, task, regs) == 0) {
-                        show_trace_unwind(&info, log_lvl);
-                        return;
+        if (call_trace >= 0) {
+                int unw_ret = 0;
+                struct unwind_frame_info info;
+
+                if (regs) {
+                        if (unwind_init_frame_info(&info, task, regs) == 0)
+                                unw_ret = show_trace_unwind(&info, log_lvl);
+                } else if (task == current)
+                        unw_ret = unwind_init_running(&info, show_trace_unwind, log_lvl);
+                else {
+                        if (unwind_init_blocked(&info, task) == 0)
+                                unw_ret = show_trace_unwind(&info, log_lvl);
                 }
-        } else if (task == current) {
-                if (unwind_init_running(&info, show_trace_unwind, log_lvl) == 0)
-                        return;
-        } else {
-                if (unwind_init_blocked(&info, task) == 0) {
-                        show_trace_unwind(&info, log_lvl);
-                        return;
+                if (unw_ret > 0) {
+                        if (call_trace > 0)
+                                return;
+                        printk("%sLegacy call trace:\n", log_lvl);
                 }
         }
 
@@ -1245,3 +1253,15 @@ static int __init kstack_setup(char *s)
         return 1;
 }
 __setup("kstack=", kstack_setup);
+
+static int __init call_trace_setup(char *s)
+{
+        if (strcmp(s, "old") == 0)
+                call_trace = -1;
+        else if (strcmp(s, "both") == 0)
+                call_trace = 0;
+        else if (strcmp(s, "new") == 0)
+                call_trace = 1;
+        return 1;
+}
+__setup("call_trace=", call_trace_setup);
diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index eb1534ff1f5f..bd0891f4c2c7 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -107,6 +107,7 @@ static inline void preempt_conditional_cli(struct pt_regs *regs)
 }
 
 static int kstack_depth_to_print = 10;
+static int call_trace = 1;
 
 #ifdef CONFIG_KALLSYMS
 #include <linux/kallsyms.h> 
@@ -190,11 +191,12 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
         return NULL;
 }
 
-static void show_trace_unwind(struct unwind_frame_info *info, void *context)
+static int show_trace_unwind(struct unwind_frame_info *info, void *context)
 {
-        int i = 11;
+        int i = 11, n = 0;
 
         while (unwind(info) == 0 && UNW_PC(info)) {
+                ++n;
                 if (i > 50) {
                         printk("\n       ");
                         i = 7;
@@ -205,6 +207,7 @@ static void show_trace_unwind(struct unwind_frame_info *info, void *context)
                         break;
         }
         printk("\n");
+        return n;
 }
 
 /*
@@ -218,27 +221,32 @@ void show_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s
 {
         const unsigned cpu = safe_smp_processor_id();
         unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr;
-        int i;
+        int i = 11;
         unsigned used = 0;
-        struct unwind_frame_info info;
 
         printk("\nCall Trace:");
 
         if (!tsk)
                 tsk = current;
 
-        if (regs) {
-                if (unwind_init_frame_info(&info, tsk, regs) == 0) {
-                        show_trace_unwind(&info, NULL);
-                        return;
+        if (call_trace >= 0) {
+                int unw_ret = 0;
+                struct unwind_frame_info info;
+
+                if (regs) {
+                        if (unwind_init_frame_info(&info, tsk, regs) == 0)
+                                unw_ret = show_trace_unwind(&info, NULL);
+                } else if (tsk == current)
+                        unw_ret = unwind_init_running(&info, show_trace_unwind, NULL);
+                else {
+                        if (unwind_init_blocked(&info, tsk) == 0)
+                                unw_ret = show_trace_unwind(&info, NULL);
                 }
-        } else if (tsk == current) {
-                if (unwind_init_running(&info, show_trace_unwind, NULL) == 0)
-                        return;
-        } else {
-                if (unwind_init_blocked(&info, tsk) == 0) {
-                        show_trace_unwind(&info, NULL);
-                        return;
+                if (unw_ret > 0) {
+                        if (call_trace > 0)
+                                return;
+                        printk("Legacy call trace:");
+                        i = 18;
                 }
         }
 
@@ -264,7 +272,7 @@ void show_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s
                 } \
         } while (0)
 
-        for(i = 11; ; ) {
+        for(; ; ) {
                 const char *id;
                 unsigned long *estack_end;
                 estack_end = in_exception_stack(cpu, (unsigned long)stack,
@@ -1052,3 +1060,14 @@ static int __init kstack_setup(char *s)
 }
 __setup("kstack=", kstack_setup);
 
+static int __init call_trace_setup(char *s)
+{
+        if (strcmp(s, "old") == 0)
+                call_trace = -1;
+        else if (strcmp(s, "both") == 0)
+                call_trace = 0;
+        else if (strcmp(s, "new") == 0)
+                call_trace = 1;
+        return 1;
+}
+__setup("call_trace=", call_trace_setup);
diff --git a/include/asm-i386/unwind.h b/include/asm-i386/unwind.h
index 1c076897ac21..d480f2e38215 100644
--- a/include/asm-i386/unwind.h
+++ b/include/asm-i386/unwind.h
@@ -66,10 +66,10 @@ static inline void arch_unw_init_blocked(struct unwind_frame_info *info)
         info->regs.xes = __USER_DS;
 }
 
-extern asmlinkage void arch_unwind_init_running(struct unwind_frame_info *,
-                                                asmlinkage void (*callback)(struct unwind_frame_info *,
-                                                                            void *arg),
-                                                void *arg);
+extern asmlinkage int arch_unwind_init_running(struct unwind_frame_info *,
+                                               asmlinkage int (*callback)(struct unwind_frame_info *,
+                                                                          void *arg),
+                                               void *arg);
 
 static inline int arch_unw_user_mode(const struct unwind_frame_info *info)
 {
diff --git a/include/asm-x86_64/unwind.h b/include/asm-x86_64/unwind.h
index 4f61de246179..f3e7124effe3 100644
--- a/include/asm-x86_64/unwind.h
+++ b/include/asm-x86_64/unwind.h
@@ -75,10 +75,10 @@ static inline void arch_unw_init_blocked(struct unwind_frame_info *info)
         info->regs.ss = __KERNEL_DS;
 }
 
-extern void arch_unwind_init_running(struct unwind_frame_info *,
-                                     void (*callback)(struct unwind_frame_info *,
-                                                      void *arg),
-                                     void *arg);
+extern int arch_unwind_init_running(struct unwind_frame_info *,
+                                    int (*callback)(struct unwind_frame_info *,
+                                                    void *arg),
+                                    void *arg);
 
 static inline int arch_unw_user_mode(const struct unwind_frame_info *info)
 {
diff --git a/include/linux/unwind.h b/include/linux/unwind.h
index 0295aa789ab4..13c7b2cd87ce 100644
--- a/include/linux/unwind.h
+++ b/include/linux/unwind.h
@@ -49,8 +49,8 @@ extern int unwind_init_blocked(struct unwind_frame_info *,
  * Prepare to unwind the currently running thread.
  */
 extern int unwind_init_running(struct unwind_frame_info *,
-                               asmlinkage void (*callback)(struct unwind_frame_info *,
-                                                           void *arg),
+                               asmlinkage int (*callback)(struct unwind_frame_info *,
+                                                          void *arg),
                                void *arg);
 
 /*
@@ -97,8 +97,8 @@ static inline int unwind_init_blocked(struct unwind_frame_info *info,
 }
 
 static inline int unwind_init_running(struct unwind_frame_info *info,
-                                      asmlinkage void (*cb)(struct unwind_frame_info *,
-                                                            void *arg),
+                                      asmlinkage int (*cb)(struct unwind_frame_info *,
+                                                           void *arg),
                                       void *arg)
 {
         return -ENOSYS;
diff --git a/kernel/unwind.c b/kernel/unwind.c
index d36bcd3ad3b5..0421035272d9 100644
--- a/kernel/unwind.c
+++ b/kernel/unwind.c
@@ -885,14 +885,13 @@ EXPORT_SYMBOL(unwind_init_blocked);
  * Prepare to unwind the currently running thread.
  */
 int unwind_init_running(struct unwind_frame_info *info,
-                        asmlinkage void (*callback)(struct unwind_frame_info *,
-                                                    void *arg),
+                        asmlinkage int (*callback)(struct unwind_frame_info *,
+                                                   void *arg),
                         void *arg)
 {
         info->task = current;
-        arch_unwind_init_running(info, callback, arg);
 
-        return 0;
+        return arch_unwind_init_running(info, callback, arg);
 }
 EXPORT_SYMBOL(unwind_init_running);