linux-kernel - [PATCH v2] x86: fix output of show_stack_log

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Message-Id: <1424399661-20327-1-git-send-email-adrien+dev@schischi.me>
Date:	Fri, 20 Feb 2015 03:34:21 +0100
From:	Adrien Schildknecht <adrien+dev@...ischi.me>
To:	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
	x86@...nel.org, rostedt@...dmis.org, heukelum@...tmail.fm,
	luto@...capital.net, adech.fo@...il.com,
	masami.hiramatsu.pt@...achi.com, akpm@...ux-foundation.org,
	a.ryabinin@...sung.com, fruggeri@...sta.com, bp@...en8.de
Cc:	linux-kernel@...r.kernel.org,
	Adrien Schildknecht <adrien+dev@...ischi.me>
Subject: [PATCH v2] x86: fix output of show_stack_log_lvl()

show_stack_log_lvl() does not set the log level after a new line,
the following messages printed with pr_cont are thus assigned to the
default log level.
This patch prepends the log level to the next message following a new
line.

print_trace_address() uses printk(log_lvl). Using printk with just
a log level is ignored and thus has no effect on the next pr_cont.
We need to prepend the log level directly into the message.

Signed-off-by: Adrien Schildknecht <adrien+dev@...ischi.me>
---
 arch/x86/kernel/dumpstack.c    | 11 ++++++-----
 arch/x86/kernel/dumpstack_32.c |  9 ++++++---
 arch/x86/kernel/dumpstack_64.c |  9 ++++++---
 3 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index cf3df1d..81b3932 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -25,10 +25,12 @@ unsigned int code_bytes = 64;
 int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
 static int die_counter;
 
-static void printk_stack_address(unsigned long address, int reliable)
+static void printk_stack_address(unsigned long address, int reliable,
+		void *data)
 {
-	pr_cont(" [<%p>] %s%pB\n",
-		(void *)address, reliable ? "" : "? ", (void *)address);
+	printk("%s [<%p>] %s%pB\n",
+		(char *)data, (void *)address, reliable ? "" : "? ",
+		(void *)address);
 }
 
 void printk_address(unsigned long address)
@@ -155,8 +157,7 @@ static int print_trace_stack(void *data, char *name)
 static void print_trace_address(void *data, unsigned long addr, int reliable)
 {
 	touch_nmi_watchdog();
-	printk(data);
-	printk_stack_address(addr, reliable);
+	printk_stack_address(addr, reliable, data);
 }
 
 static const struct stacktrace_ops print_trace_ops = {
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 5abd4cd..efff5ed 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -108,9 +108,12 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 	for (i = 0; i < kstack_depth_to_print; i++) {
 		if (kstack_end(stack))
 			break;
-		if (i && ((i % STACKSLOTS_PER_LINE) == 0))
-			pr_cont("\n");
-		pr_cont(" %08lx", *stack++);
+		if ((i % STACKSLOTS_PER_LINE) == 0) {
+			if (i != 0)
+				pr_cont("\n");
+			printk("%s %08lx", log_lvl, *stack++);
+		} else
+			pr_cont(" %08lx", *stack++);
 		touch_nmi_watchdog();
 	}
 	pr_cont("\n");
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index ff86f19..553573b 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -283,9 +283,12 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 		if (((long) stack & (THREAD_SIZE-1)) == 0)
 			break;
 		}
-		if (i && ((i % STACKSLOTS_PER_LINE) == 0))
-			pr_cont("\n");
-		pr_cont(" %016lx", *stack++);
+		if ((i % STACKSLOTS_PER_LINE) == 0) {
+			if (i != 0)
+				pr_cont("\n");
+			printk("%s %016lx", log_lvl, *stack++);
+		} else
+			pr_cont(" %016lx", *stack++);
 		touch_nmi_watchdog();
 	}
 	preempt_enable();
-- 
2.2.1

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