s390/dumpstack: restore reliable indicator for call traces

commit d0208639dbc6fe97a25054df44faa2d19aca9380 upstream.

Before merging all different stack tracers the call traces printed had
an indicator if an entry can be considered reliable or not.
Unreliable entries were put in braces, reliable not. Currently all
lines contain these extra braces.

This patch restores the old behaviour by adding an extra "reliable"
parameter to the callback functions. Only show_trace makes currently
use of it.

Before:
[    0.804751] Call Trace:
[    0.804753] ([<000000000017d0e0>] try_to_wake_up+0x318/0x5e0)
[    0.804756] ([<0000000000161d64>] create_worker+0x174/0x1c0)

After:
[    0.804751] Call Trace:
[    0.804753] ([<000000000017d0e0>] try_to_wake_up+0x318/0x5e0)
[    0.804756]  [<0000000000161d64>] create_worker+0x174/0x1c0

Fixes: 758d39ebd3d5 ("s390/dumpstack: merge all four stack tracers")
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

5 files changed, 16 insertions, 11 deletions

diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 03323175de30..602af692efdc 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -192,7 +192,7 @@ struct task_struct;
 struct mm_struct;
 struct seq_file;
 
-typedef int (*dump_trace_func_t)(void *data, unsigned long address);
+typedef int (*dump_trace_func_t)(void *data, unsigned long address, int reliable);
 void dump_trace(dump_trace_func_t func, void *data,
 		struct task_struct *task, unsigned long sp);
 
diff --git a/arch/s390/kernel/dumpstack.c b/arch/s390/kernel/dumpstack.c
index 6693383bc01b..518f615ad0a2 100644
--- a/arch/s390/kernel/dumpstack.c
+++ b/arch/s390/kernel/dumpstack.c
@@ -38,10 +38,10 @@ __dump_trace(dump_trace_func_t func, void *data, unsigned long sp,
 		if (sp < low || sp > high - sizeof(*sf))
 			return sp;
 		sf = (struct stack_frame *) sp;
+		if (func(data, sf->gprs[8], 0))
+			return sp;
 		/* Follow the backchain. */
 		while (1) {
-			if (func(data, sf->gprs[8]))
-				return sp;
 			low = sp;
 			sp = sf->back_chain;
 			if (!sp)
@@ -49,6 +49,8 @@ __dump_trace(dump_trace_func_t func, void *data, unsigned long sp,
 			if (sp <= low || sp > high - sizeof(*sf))
 				return sp;
 			sf = (struct stack_frame *) sp;
+			if (func(data, sf->gprs[8], 1))
+				return sp;
 		}
 		/* Zero backchain detected, check for interrupt frame. */
 		sp = (unsigned long) (sf + 1);
@@ -56,7 +58,7 @@ __dump_trace(dump_trace_func_t func, void *data, unsigned long sp,
 			return sp;
 		regs = (struct pt_regs *) sp;
 		if (!user_mode(regs)) {
-			if (func(data, regs->psw.addr))
+			if (func(data, regs->psw.addr, 1))
 				return sp;
 		}
 		low = sp;
@@ -90,7 +92,7 @@ struct return_address_data {
 	int depth;
 };
 
-static int __return_address(void *data, unsigned long address)
+static int __return_address(void *data, unsigned long address, int reliable)
 {
 	struct return_address_data *rd = data;
 
@@ -109,9 +111,12 @@ unsigned long return_address(int depth)
 }
 EXPORT_SYMBOL_GPL(return_address);
 
-static int show_address(void *data, unsigned long address)
+static int show_address(void *data, unsigned long address, int reliable)
 {
-	printk("([<%016lx>] %pSR)\n", address, (void *)address);
+	if (reliable)
+		printk(" [<%016lx>] %pSR \n", address, (void *)address);
+	else
+		printk("([<%016lx>] %pSR)\n", address, (void *)address);
 	return 0;
 }
 
diff --git a/arch/s390/kernel/perf_event.c b/arch/s390/kernel/perf_event.c
index 17431f63de00..955a7b6fa0a4 100644
--- a/arch/s390/kernel/perf_event.c
+++ b/arch/s390/kernel/perf_event.c
@@ -222,7 +222,7 @@ static int __init service_level_perf_register(void)
 }
 arch_initcall(service_level_perf_register);
 
-static int __perf_callchain_kernel(void *data, unsigned long address)
+static int __perf_callchain_kernel(void *data, unsigned long address, int reliable)
 {
 	struct perf_callchain_entry_ctx *entry = data;
 
diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
index 44f84b23d4e5..355db9db8210 100644
--- a/arch/s390/kernel/stacktrace.c
+++ b/arch/s390/kernel/stacktrace.c
@@ -27,12 +27,12 @@ static int __save_address(void *data, unsigned long address, int nosched)
 	return 1;
 }
 
-static int save_address(void *data, unsigned long address)
+static int save_address(void *data, unsigned long address, int reliable)
 {
 	return __save_address(data, address, 0);
 }
 
-static int save_address_nosched(void *data, unsigned long address)
+static int save_address_nosched(void *data, unsigned long address, int reliable)
 {
 	return __save_address(data, address, 1);
 }
diff --git a/arch/s390/oprofile/init.c b/arch/s390/oprofile/init.c
index 16f4c3960b87..9a4de4599c7b 100644
--- a/arch/s390/oprofile/init.c
+++ b/arch/s390/oprofile/init.c
@@ -13,7 +13,7 @@
 #include <linux/init.h>
 #include <asm/processor.h>
 
-static int __s390_backtrace(void *data, unsigned long address)
+static int __s390_backtrace(void *data, unsigned long address, int reliable)
 {
 	unsigned int *depth = data;