From: Cengiz Can <cengiz@kernel.wtf>
To: daniel.thompson@linaro.org
Cc: andriy.shevchenko@linux.intel.com, cengiz@kernel.wtf,
dianders@chromium.org, jason.wessel@windriver.com,
kgdb-bugreport@lists.sourceforge.net,
linux-kernel@vger.kernel.org, pmladek@suse.com,
sumit.garg@linaro.org
Subject: [PATCH v2] kdb: remove unnecessary null check of dbg_io_ops
Date: Mon, 29 Jun 2020 23:50:13 +0300 [thread overview]
Message-ID: <20200629205012.3263-1-cengiz@kernel.wtf> (raw)
In-Reply-To: <20200629153756.cxg74nec3repa4lu@holly.lan>
`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 | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 683a799618ad..4ac59a4fbeec 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -549,14 +549,12 @@ static void kdb_msg_write(const char *msg, int msg_len)
if (msg_len == 0)
return;
- if (dbg_io_ops) {
- const char *cp = msg;
- int len = msg_len;
+ const char *cp = msg;
+ int 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:[~2020-06-29 20:50 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 ` Cengiz Can [this message]
2020-06-29 21:16 ` [PATCH v2] kdb: remove unnecessary null check of dbg_io_ops 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 ` [PATCH v3] kdb: remove unnecessary null check of dbg_io_ops Cengiz Can
2020-06-30 11:36 ` 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
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