5e512be069
[ Upstream commit 2f7ee2a72ccec8b85a05c4644d7ec9f40c1c50c8 ]
Kbuild spotted the following bug during the testing of one of
the optimizations:
In file included from include/linux/cpumask.h:12,
[...]
from drivers/net/ethernet/intel/ice/ice_switch.c:4:
drivers/net/ethernet/intel/ice/ice_switch.c: In function 'ice_find_free_recp_res_idx.constprop':
include/linux/bitmap.h:447:22: warning: 'possible_idx[0]' is used uninitialized [-Wuninitialized]
447 | *map |= GENMASK(start + nbits - 1, start);
| ^~
In file included from drivers/net/ethernet/intel/ice/ice.h:7,
from drivers/net/ethernet/intel/ice/ice_lib.h:7,
from drivers/net/ethernet/intel/ice/ice_switch.c:4:
drivers/net/ethernet/intel/ice/ice_switch.c:4929:24: note: 'possible_idx[0]' was declared here
4929 | DECLARE_BITMAP(possible_idx, ICE_MAX_FV_WORDS);
| ^~~~~~~~~~~~
include/linux/types.h:11:23: note: in definition of macro 'DECLARE_BITMAP'
11 | unsigned long name[BITS_TO_LONGS(bits)]
| ^~~~
%ICE_MAX_FV_WORDS is 48, so bitmap_set() here was initializing only
48 bits, leaving a junk in the rest 16.
It was previously hidden due to that filling 48 bits makes
bitmap_set() call external __bitmap_set(), but after making it use
plain bit arithmetics on small bitmaps, compilers started seeing
the issue. It was still working because those 16 weren't used
anywhere anyhow.
bitmap_{clear,set}() are not really intended to initialize bitmaps,
rather to modify already initialized ones, as they don't do anything
past the passed number of bits. The correct function to do this in
that particular case is bitmap_fill(), so use it here. It will do
`*possible_idx = ~0UL` instead of `*possible_idx |= GENMASK(47, 0)`,
not leaving anything in an undefined state.
Fixes: fd2a6b71e300 ("ice: create advanced switch recipe")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.