linux-kernel - [PATCH v3] kdb: remove unnecessary null check of dbg_io

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Date:   Tue, 30 Jun 2020 11:29:23 +0300
From:   Cengiz Can <cengiz@...nel.wtf>
To:     sumit.garg@...aro.org
Cc:     andriy.shevchenko@...ux.intel.com, cengiz@...nel.wtf,
        daniel.thompson@...aro.org, dianders@...omium.org,
        jason.wessel@...driver.com, kgdb-bugreport@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, pmladek@...e.com
Subject: [PATCH v3] kdb: remove unnecessary null check of dbg_io_ops

`kdb_msg_write` operates on a global `struct kgdb_io *` called
`dbg_io_ops`.

It's initialized in `debug_core.c` and checked throughout the debug
flow.

There's a null check in `kdb_msg_write` which triggers static analyzers
and gives the (almost entirely wrong) impression that it can be null.

Coverity scanner caught this as CID 1465042.

I have removed the unnecessary null check and eliminated false-positive
forward null dereference warning.

Signed-off-by: Cengiz Can <cengiz@...nel.wtf>
---
 kernel/debug/kdb/kdb_io.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 683a799618ad..81783ecaec58 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -545,18 +545,18 @@ static int kdb_search_string(char *searched, char *searchfor)
 static void kdb_msg_write(const char *msg, int msg_len)
 {
 	struct console *c;
+	const char *cp;
+	int len;
 
 	if (msg_len == 0)
 		return;
 
-	if (dbg_io_ops) {
-		const char *cp = msg;
-		int len = msg_len;
+	cp = msg;
+	len = msg_len;
 
-		while (len--) {
-			dbg_io_ops->write_char(*cp);
-			cp++;
-		}
+	while (len--) {
+		dbg_io_ops->write_char(*cp);
+		cp++;
 	}
 
 	for_each_console(c) {
-- 
2.27.0