From: Cengiz Can <cengiz@kernel.wtf>
To: sumit.garg@linaro.org
Cc: andriy.shevchenko@linux.intel.com, cengiz@kernel.wtf,
daniel.thompson@linaro.org, dianders@chromium.org,
jason.wessel@windriver.com, kgdb-bugreport@lists.sourceforge.net,
linux-kernel@vger.kernel.org, pmladek@suse.com
Subject: [PATCH v3] kdb: remove unnecessary null check of dbg_io_ops
Date: Tue, 30 Jun 2020 11:29:23 +0300 [thread overview]
Message-ID: <20200630082922.28672-1-cengiz@kernel.wtf> (raw)
In-Reply-To: <CAFA6WYNpCG2xPERd=NeKf+EthbX+1R4iieOL52kWnBp8y_+Nbw@mail.gmail.com>
`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@kernel.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
next prev parent reply other threads:[~2020-06-30 8:30 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-29 13:59 [PATCH] kdb: prevent possible null deref in kdb_msg_write Cengiz Can
2020-06-29 14:27 ` Daniel Thompson
2020-06-29 14:50 ` Petr Mladek
2020-06-29 14:53 ` Petr Mladek
2020-06-29 15:37 ` Daniel Thompson
2020-06-29 20:50 ` [PATCH v2] kdb: remove unnecessary null check of dbg_io_ops Cengiz Can
2020-06-29 21:16 ` Doug Anderson
2020-06-29 22:10 ` Cengiz Can
2020-06-30 5:55 ` [PATCH] kdb: prevent possible null deref in kdb_msg_write Sumit Garg
2020-06-30 8:29 ` Cengiz Can [this message]
2020-06-30 11:36 ` [PATCH v3] kdb: remove unnecessary null check of dbg_io_ops Sumit Garg
2020-06-30 11:48 ` Andy Shevchenko
2020-06-30 22:32 ` Doug Anderson
2020-07-10 12:15 ` Cengiz Can
2020-07-10 13:41 ` Daniel Thompson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200630082922.28672-1-cengiz@kernel.wtf \
--to=cengiz@kernel.wtf \
--cc=andriy.shevchenko@linux.intel.com \
--cc=daniel.thompson@linaro.org \
--cc=dianders@chromium.org \
--cc=jason.wessel@windriver.com \
--cc=kgdb-bugreport@lists.sourceforge.net \
--cc=linux-kernel@vger.kernel.org \
--cc=pmladek@suse.com \
--cc=sumit.garg@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).