linux-kernel - [PATCH 47/50] kdb: Don't play with console

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Message-Id: <20191106030542.868541-48-dima@arista.com>
Date:   Wed,  6 Nov 2019 03:05:38 +0000
From:   Dmitry Safonov <dima@...sta.com>
To:     linux-kernel@...r.kernel.org
Cc:     Dmitry Safonov <0x7f454c46@...il.com>,
        Dmitry Safonov <dima@...sta.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Ingo Molnar <mingo@...nel.org>, Jiri Slaby <jslaby@...e.com>,
        Petr Mladek <pmladek@...e.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Douglas Anderson <dianders@...omium.org>,
        Jason Wessel <jason.wessel@...driver.com>,
        kgdb-bugreport@...ts.sourceforge.net
Subject: [PATCH 47/50] kdb: Don't play with console_loglevel

Print the stack trace with KERN_EMERG - it should be always visible.

Playing with console_loglevel is a bad idea as there may be more
messages printed than wanted. Also the stack trace might be not printed
at all if printk() was deferred and console_loglevel was raised back
before the trace got flushed.

Cc: Daniel Thompson <daniel.thompson@...aro.org>
Cc: Douglas Anderson <dianders@...omium.org>
Cc: Jason Wessel <jason.wessel@...driver.com>
Cc: kgdb-bugreport@...ts.sourceforge.net
Signed-off-by: Dmitry Safonov <dima@...sta.com>
---
 kernel/debug/kdb/kdb_bt.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
index 7e2379aa0a1e..5ce1fe082a38 100644
--- a/kernel/debug/kdb/kdb_bt.c
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -21,22 +21,19 @@
 
 static void kdb_show_stack(struct task_struct *p, void *addr)
 {
-	int old_lvl = console_loglevel;
-	console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
 	kdb_trap_printk++;
 	kdb_set_current_task(p);
 	if (addr) {
-		show_stack((struct task_struct *)p, addr);
+		show_stack_loglvl(p, addr, KERN_EMERG);
 	} else if (kdb_current_regs) {
 #ifdef CONFIG_X86
-		show_stack(p, &kdb_current_regs->sp);
+		show_stack_loglvl(p, &kdb_current_regs->sp, KERN_EMERG);
 #else
-		show_stack(p, NULL);
+		show_stack_loglvl(p, NULL, KERN_EMERG);
 #endif
 	} else {
-		show_stack(p, NULL);
+		show_stack_loglvl(p, NULL, KERN_EMERG);
 	}
-	console_loglevel = old_lvl;
 	kdb_trap_printk--;
 }
 
-- 
2.23.0