net/ceph/osdmap.c:1246:10: warning: result of comparison of constant 4611686018427387891 with expression of type 'u32' (aka 'unsigned int') is always false

From: kernel test robot
Date: Sun Nov 05 2023 - 18:29:41 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 77fa2fbe87fc605c4bfa87dff87be9bfded0e9a3
commit: afe956c577b2d5a3d9834e4424587c1ebcf90c4c kbuild: Enable -Wtautological-compare
date: 3 years, 7 months ago
config: x86_64-randconfig-012-20230909 (https://download.01.org/0day-ci/archive/20231106/202311060702.EjNPjAwj-lkp@xxxxxxxxx/config)
compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231106/202311060702.EjNPjAwj-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202311060702.EjNPjAwj-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

net/ceph/osdmap.c:176:6: warning: no previous prototype for function 'clear_choose_args' [-Wmissing-prototypes]
void clear_choose_args(struct crush_map *c)
^
net/ceph/osdmap.c:176:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void clear_choose_args(struct crush_map *c)
^
static
>> net/ceph/osdmap.c:1246:10: warning: result of comparison of constant 4611686018427387891 with expression of type 'u32' (aka 'unsigned int') is always false [-Wtautological-constant-out-of-range-compare]
if (len > (SIZE_MAX - sizeof(*pg)) / sizeof(u32))
~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
net/ceph/osdmap.c:1429:10: warning: result of comparison of constant 2305843009213693945 with expression of type 'u32' (aka 'unsigned int') is always false [-Wtautological-constant-out-of-range-compare]
if (len > (SIZE_MAX - sizeof(*pg)) / (2 * sizeof(u32)))
~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3 warnings generated.
--
>> drivers/block/rbd.c:6190:17: warning: result of comparison of constant 2305843009213693948 with expression of type 'u32' (aka 'unsigned int') is always false [-Wtautological-constant-out-of-range-compare]
if (snap_count > (SIZE_MAX - sizeof (struct ceph_snap_context))
~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 warning generated.


vim +1246 net/ceph/osdmap.c

10db634e2083a2 Ilya Dryomov 2014-03-21 1236
a303bb0e58345f Ilya Dryomov 2017-06-21 1237 static struct ceph_pg_mapping *__decode_pg_temp(void **p, void *end,
a303bb0e58345f Ilya Dryomov 2017-06-21 1238 bool incremental)
a303bb0e58345f Ilya Dryomov 2017-06-21 1239 {
a303bb0e58345f Ilya Dryomov 2017-06-21 1240 struct ceph_pg_mapping *pg;
a303bb0e58345f Ilya Dryomov 2017-06-21 1241 u32 len, i;
a303bb0e58345f Ilya Dryomov 2017-06-21 1242
a303bb0e58345f Ilya Dryomov 2017-06-21 1243 ceph_decode_32_safe(p, end, len, e_inval);
a303bb0e58345f Ilya Dryomov 2017-06-21 1244 if (len == 0 && incremental)
a303bb0e58345f Ilya Dryomov 2017-06-21 1245 return NULL; /* new_pg_temp: [] to remove */
a303bb0e58345f Ilya Dryomov 2017-06-21 @1246 if (len > (SIZE_MAX - sizeof(*pg)) / sizeof(u32))
a303bb0e58345f Ilya Dryomov 2017-06-21 1247 return ERR_PTR(-EINVAL);
a303bb0e58345f Ilya Dryomov 2017-06-21 1248
a303bb0e58345f Ilya Dryomov 2017-06-21 1249 ceph_decode_need(p, end, len * sizeof(u32), e_inval);
a303bb0e58345f Ilya Dryomov 2017-06-21 1250 pg = alloc_pg_mapping(len * sizeof(u32));
10db634e2083a2 Ilya Dryomov 2014-03-21 1251 if (!pg)
a303bb0e58345f Ilya Dryomov 2017-06-21 1252 return ERR_PTR(-ENOMEM);
10db634e2083a2 Ilya Dryomov 2014-03-21 1253
35a935d75d51ab Ilya Dryomov 2014-03-21 1254 pg->pg_temp.len = len;
10db634e2083a2 Ilya Dryomov 2014-03-21 1255 for (i = 0; i < len; i++)
35a935d75d51ab Ilya Dryomov 2014-03-21 1256 pg->pg_temp.osds[i] = ceph_decode_32(p);
10db634e2083a2 Ilya Dryomov 2014-03-21 1257
a303bb0e58345f Ilya Dryomov 2017-06-21 1258 return pg;
10db634e2083a2 Ilya Dryomov 2014-03-21 1259
10db634e2083a2 Ilya Dryomov 2014-03-21 1260 e_inval:
a303bb0e58345f Ilya Dryomov 2017-06-21 1261 return ERR_PTR(-EINVAL);
10db634e2083a2 Ilya Dryomov 2014-03-21 1262 }
10db634e2083a2 Ilya Dryomov 2014-03-21 1263

:::::: The code at line 1246 was first introduced by commit
:::::: a303bb0e58345fe9f7ab2f82b90266f2b5036058 libceph: introduce and switch to decode_pg_mapping()

:::::: TO: Ilya Dryomov <idryomov@xxxxxxxxx>
:::::: CC: Ilya Dryomov <idryomov@xxxxxxxxx>

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