From: Richard Fitzgerald <rf@opensource.cirrus.com>
To: <pmladek@suse.com>, <rostedt@goodmis.org>,
<sergey.senozhatsky@gmail.com>,
<andriy.shevchenko@linux.intel.com>, <linux@rasmusvillemoes.dk>,
<w@1wt.eu>, <lkml@sdf.org>, <davem@davemloft.net>,
<kuba@kernel.org>
Cc: <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<patches@opensource.cirrus.com>,
Richard Fitzgerald <rf@opensource.cirrus.com>
Subject: [PATCH 1/2] lib: test_scanf: Fix incorrect use of type_min() with unsigned types
Date: Mon, 24 May 2021 16:59:40 +0100 [thread overview]
Message-ID: <20210524155941.16376-2-rf@opensource.cirrus.com> (raw)
In-Reply-To: <20210524155941.16376-1-rf@opensource.cirrus.com>
sparse was producing warnings of the form:
sparse: cast truncates bits from constant value (ffff0001 becomes 1)
The problem was that value_representable_in_type() compared unsigned types
against type_min(). But type_min() is only valid for signed types because
it is calculating the value -type_max() - 1. The minimum value of an
unsigned is obviously 0, so only type_max() need be tested.
This patch also takes the opportunity to clean up the implementation of
simple_numbers_loop() to use a common pattern for the positive and
negative test.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 17aadada455d ("lib: test_scanf: Add tests for sscanf number conversion")
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
---
lib/test_scanf.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/lib/test_scanf.c b/lib/test_scanf.c
index 8d577aec6c28..48ff5747a4da 100644
--- a/lib/test_scanf.c
+++ b/lib/test_scanf.c
@@ -187,8 +187,8 @@ static const unsigned long long numbers[] __initconst = {
#define value_representable_in_type(T, val) \
(is_signed_type(T) \
? ((long long)(val) >= type_min(T)) && ((long long)(val) <= type_max(T)) \
- : ((unsigned long long)(val) >= type_min(T)) && \
- ((unsigned long long)(val) <= type_max(T)))
+ : ((unsigned long long)(val) <= type_max(T)))
+
#define test_one_number(T, gen_fmt, scan_fmt, val, fn) \
do { \
@@ -204,12 +204,11 @@ do { \
int i; \
\
for (i = 0; i < ARRAY_SIZE(numbers); i++) { \
- if (!value_representable_in_type(T, numbers[i])) \
- continue; \
- \
- test_one_number(T, gen_fmt, scan_fmt, numbers[i], fn); \
+ if (value_representable_in_type(T, numbers[i])) \
+ test_one_number(T, gen_fmt, scan_fmt, \
+ numbers[i], fn); \
\
- if (is_signed_type(T)) \
+ if (value_representable_in_type(T, -numbers[i])) \
test_one_number(T, gen_fmt, scan_fmt, \
-numbers[i], fn); \
} \
--
2.20.1
next prev parent reply other threads:[~2021-05-24 16:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-24 15:59 [PATCH 0/2] Fix truncation warnings from building test_scanf.c Richard Fitzgerald
2021-05-24 15:59 ` Richard Fitzgerald [this message]
2021-05-25 9:55 ` [PATCH 1/2] lib: test_scanf: Fix incorrect use of type_min() with unsigned types Rasmus Villemoes
2021-05-25 10:10 ` Richard Fitzgerald
2021-05-25 10:30 ` Rasmus Villemoes
2021-05-27 21:59 ` Luc Van Oostenryck
2021-05-24 15:59 ` [PATCH 2/2] random32: Fix implicit truncation warning in prandom_seed_state() Richard Fitzgerald
2021-05-25 9:20 ` [PATCH 0/2] Fix truncation warnings from building test_scanf.c Petr Mladek
2021-05-27 14:10 ` Petr Mladek
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=20210524155941.16376-2-rf@opensource.cirrus.com \
--to=rf@opensource.cirrus.com \
--cc=andriy.shevchenko@linux.intel.com \
--cc=davem@davemloft.net \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
--cc=lkml@sdf.org \
--cc=netdev@vger.kernel.org \
--cc=patches@opensource.cirrus.com \
--cc=pmladek@suse.com \
--cc=rostedt@goodmis.org \
--cc=sergey.senozhatsky@gmail.com \
--cc=w@1wt.eu \
/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).