linux-kernel - [PATCH] kdb: Avoid using dbg_io

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Message-ID: <4E7A46C0.6010804@am.sony.com>
Date:	Wed, 21 Sep 2011 13:19:12 -0700
From:	Tim Bird <tim.bird@...sony.com>
To:	Jason Wessel <jason.wessel@...driver.com>
CC:	"kgdb-bugreport@...ts.sourceforge.net" 
	<kgdb-bugreport@...ts.sourceforge.net>,
	linux kernel <linux-kernel@...r.kernel.org>
Subject: [PATCH] kdb:  Avoid using dbg_io_ops until it is initialized

This fixes a bug with setting a breakpoint during kdb initialization
(from kdb_cmds).  Any call to kdb_printf() before the initialization
of the kgdboc serial console driver (which happens much later during
bootup than kdb_init), results in kernel panic due to the use of
dbg_io_ops before it is initialized.

Signed-off-by: Tim Bird <tim.bird@...sony.com>
---
 kernel/debug/kdb/kdb_io.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index c9b7f4f..3bc995f 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -675,7 +675,7 @@ kdb_printit:
 	if (!dbg_kdb_mode && kgdb_connected) {
 		gdbstub_msg_write(kdb_buffer, retlen);
 	} else {
-		if (!dbg_io_ops->is_console) {
+		if (dbg_io_ops && !dbg_io_ops->is_console) {
 			len = strlen(kdb_buffer);
 			cp = kdb_buffer;
 			while (len--) {
-- 
1.7.2.3


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