mbox series

[v2,0/2] Fix truncation warnings from building test_scanf.c

Message ID 20210525110546.6223-1-rf@opensource.cirrus.com
Headers show
Series Fix truncation warnings from building test_scanf.c | expand

Message

Richard Fitzgerald May 25, 2021, 11:05 a.m. UTC 
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
truncation is expected but the use of type_min() on an unsigned is
unnecessary because we know it is always 0.

(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: Remove pointless 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(-)