[tip:sched/rt] x86/dumpstack: Indicate PREEMPT_RT in dumps

[tip-bot for Thomas Gleixner <tipbot@zytor.com>]

Commit-ID:  cb376c26971ff54f25980ec1f0ae2f06d6a69df0
Gitweb:     https://git.kernel.org/tip/cb376c26971ff54f25980ec1f0ae2f06d6a69df0
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Fri, 26 Jul 2019 23:19:43 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 31 Jul 2019 19:03:36 +0200

x86/dumpstack: Indicate PREEMPT_RT in dumps

Stack dumps print whether the kernel has preemption enabled or not. Extend
it so a PREEMPT_RT enabled kernel can be identified.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20190726212124.699136351@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/dumpstack.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 2b5886401e5f..e07424e19274 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -367,13 +367,18 @@ NOKPROBE_SYMBOL(oops_end);
 
 int __die(const char *str, struct pt_regs *regs, long err)
 {
+	const char *pr = "";
+
 	/* Save the regs of the first oops for the executive summary later. */
 	if (!die_counter)
 		exec_summary_regs = *regs;
 
+	if (IS_ENABLED(CONFIG_PREEMPTION))
+		pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT";
+
 	printk(KERN_DEFAULT
 	       "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff, ++die_counter,
-	       IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT"         : "",
+	       pr,
 	       IS_ENABLED(CONFIG_SMP)     ? " SMP"             : "",
 	       debug_pagealloc_enabled()  ? " DEBUG_PAGEALLOC" : "",
 	       IS_ENABLED(CONFIG_KASAN)   ? " KASAN"           : "",