[PATCH 0/2] Fix truncation warnings from building test_scanf.c

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 0/2] Fix truncation warnings from building test_scanf.c
Date: Mon, 24 May 2021 16:59:39 +0100	[thread overview]
Message-ID: <20210524155941.16376-1-rf@opensource.cirrus.com> (raw)

The kernel test robot is reporting truncation warnings when building
lib/test_scanf.c:

1) lib/test_scanf.c:250:9: sparse: sparse: cast truncates bits from
   constant value (ffff0001 becomes 1)
   Reported on several lines.

2) include/linux/prandom.h:114:45: sparse: sparse: cast truncates bits
   from constant value (4f2e5357408c3c09 becomes 408c3c09)

(1) is caused by test_scanf.c using type_min() on an unsigned type. The
type_min() macro calculates -type_max() - 1, so is only meaningful for
signed types.

(2) is caused by prandom_seed_state() storing a modified u64 seed value
into a u32 - sparse will warn that this causes a truncation. 

The two patches in this series fix these problems.

Richard Fitzgerald (2):
  lib: test_scanf: Fix incorrect use of type_min() with unsigned types
  random32: Fix implicit truncation warning in prandom_seed_state()

 include/linux/prandom.h |  2 +-
 lib/test_scanf.c        | 13 ++++++-------
 2 files changed, 7 insertions(+), 8 deletions(-)

-- 
2.20.1