[gourryinverse:scratch/gourry/cramtest/cram_72 90/90] cram_dropwrite_tool.c:150:13: warning: 'buf' may be used uninitialized

[gourryinverse:scratch/gourry/cramtest/cram_72 90/90] cram_dropwrite_tool.c:150:13: warning: 'buf' may be used uninitialized

[kernel test robot]

:::::: 
:::::: Manual check reason: "low confidence bisect report"
:::::: Manual check reason: "likely FALSE maybe-used-uninitialized warning on old compiler"
:::::: 

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
CC: Gregory Price <gourry@gourry.net>
TO: Gregory Price <gourry@gourry.net>

tree:   https://github.com/gourryinverse/linux scratch/gourry/cramtest/cram_72
head:   22cb35457d24fb35765ef124f9c74c08a5f546a9
commit: 22cb35457d24fb35765ef124f9c74c08a5f546a9 [90/90] selftests/dax: add CRAM write(2)-drop adversarial test
:::::: branch date: 2 days ago
:::::: commit date: 2 days ago
config: arm64-allnoconfig-bpf (https://download.01.org/0day-ci/archive/20260722/202607222023.gZPFIhHB-lkp@intel.com/config)
compiler: aarch64-linux-gnu-gcc (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260722/202607222023.gZPFIhHB-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/r/202607222023.gZPFIhHB-lkp@intel.com/

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   cram_dropwrite_tool.c: In function 'write_region':
>> cram_dropwrite_tool.c:150:13: warning: 'buf' may be used uninitialized [-Wmaybe-uninitialized]
     150 |         r = pwrite(fd, buf, n * 8, w0 * 8);
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   In file included from cram_dropwrite_tool.c:42:
   /usr/aarch64-linux-gnu/include/unistd.h:398:16: note: in a call to 'pwrite' declared with attribute 'access (read_only, 2, 3)' here
     398 | extern ssize_t pwrite (int __fd, const void *__buf, size_t __n,
         |                ^~~~~~
>> cram_dropwrite_tool.c:150:13: warning: 'pwrite' specified size between 9223372036854775808 and 18446744073709551615 exceeds maximum object size 9223372036854775807 [-Wstringop-overflow=]
     150 |         r = pwrite(fd, buf, n * 8, w0 * 8);
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   /usr/aarch64-linux-gnu/include/unistd.h:398:16: note: in a call to function 'pwrite' declared with attribute 'access (read_only, 2, 3)'
     398 | extern ssize_t pwrite (int __fd, const void *__buf, size_t __n,
         |                ^~~~~~

--
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https://github.com/intel/lkp-tests/wiki