linux-kernel - [PATCH 1/2] kdb: Fix handling of kallsyms_symbol

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Date:   Wed, 6 Dec 2017 16:33:44 -0600
From:   Jason Wessel <jason.wessel@...driver.com>
To:     <torvalds@...ux-foundation.org>
CC:     <linux-kernel@...r.kernel.org>,
        <kgdb-bugreport@...ts.sourceforge.net>
Subject: [PATCH 1/2] kdb: Fix handling of kallsyms_symbol_next() return value

From: Daniel Thompson <daniel.thompson@...aro.org>

kallsyms_symbol_next() returns a boolean (true on success). Currently
kdb_read() tests the return value with an inequality that
unconditionally evaluates to true.

This is fixed in the obvious way and, since the conditional branch is
supposed to be unreachable, we also add a WARN_ON().

Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Daniel Thompson <daniel.thompson@...aro.org>
Cc: linux-stable <stable@...r.kernel.org>
Signed-off-by: Jason Wessel <jason.wessel@...driver.com>
---
 kernel/debug/kdb/kdb_io.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index e74be38..ed5d349 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -350,7 +350,7 @@ static char *kdb_read(char *buffer, size_t bufsize)
 			}
 			kdb_printf("\n");
 			for (i = 0; i < count; i++) {
-				if (kallsyms_symbol_next(p_tmp, i) < 0)
+				if (WARN_ON(!kallsyms_symbol_next(p_tmp, i)))
 					break;
 				kdb_printf("%s ", p_tmp);
 				*(p_tmp + len) = '\0';
-- 
1.9.1