Re: [PATCH 1/2] x86: dumpstack, use pr_cont

[Rasmus Villemoes <linux@rasmusvillemoes.dk>]

On Tue, Oct 06 2015, Jiri Slaby <jslaby@suse.cz> wrote:

> When dumping flags with which the kernel was built, we print them one
> by one in separate printks. Let's use pr_cont as they are
> continuation prints.
>
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: x86@kernel.org
> ---
>  arch/x86/kernel/dumpstack.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
> index 9c30acfadae2..3850c992f767 100644
> --- a/arch/x86/kernel/dumpstack.c
> +++ b/arch/x86/kernel/dumpstack.c
> @@ -260,18 +260,18 @@ int __die(const char *str, struct pt_regs *regs, long err)
>  	printk(KERN_DEFAULT
>  	       "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
>  #ifdef CONFIG_PREEMPT
> -	printk("PREEMPT ");
> +	pr_cont("PREEMPT ");
>  #endif
>  #ifdef CONFIG_SMP
> -	printk("SMP ");
> +	pr_cont("SMP ");
>  #endif
>  #ifdef CONFIG_DEBUG_PAGEALLOC
> -	printk("DEBUG_PAGEALLOC ");
> +	pr_cont("DEBUG_PAGEALLOC");

cosmetic: this lost a space.

May I suggest 

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 9c30acfadae2..b473a47d1851 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -257,21 +257,23 @@ int __die(const char *str, struct pt_regs *regs, long err)
 	unsigned short ss;
 	unsigned long sp;
 #endif
-	printk(KERN_DEFAULT
-	       "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
+	static const char build_flags[] = ""
 #ifdef CONFIG_PREEMPT
-	printk("PREEMPT ");
+	" PREEMPT"
 #endif
 #ifdef CONFIG_SMP
-	printk("SMP ");
+	" SMP"
 #endif
 #ifdef CONFIG_DEBUG_PAGEALLOC
-	printk("DEBUG_PAGEALLOC ");
+	" DEBUG_PAGEALLOC"
 #endif
 #ifdef CONFIG_KASAN
-	printk("KASAN");
+	" KASAN"
 #endif
-	printk("\n");
+		;
+	printk(KERN_DEFAULT
+	       "%s: %04lx [#%d]%s\n", str, err & 0xffff, ++die_counter,
+		build_flags);
 	if (notify_die(DIE_OOPS, str, regs, err,
 			current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
 		return 1;

instead, so that there's only one printk call and the pr_cont issue goes
away?

Rasmus