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Subjectdrivers/block/rbd.c:2124:21: warning: 'current_state' may be used uninitialized in this function
tree:   https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 26538100499460ee81546a0dc8d6f14f5151d427
commit: 22e8bd51bb0469d1a524130a057f894ff632376a rbd: support for object-map and fast-diff
date: 8 weeks ago
config: x86_64-randconfig-s1-08301454 (attached as .config)
compiler: gcc-7 (Debian 7.4.0-11) 7.4.0
reproduce:
git checkout 22e8bd51bb0469d1a524130a057f894ff632376a
# save the attached .config to linux build tree
make ARCH=x86_64

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <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 >>):

drivers/block/rbd.c: In function 'rbd_object_map_callback':
>> drivers/block/rbd.c:2124:21: warning: 'current_state' may be used uninitialized in this function [-Wmaybe-uninitialized]
(current_state == OBJECT_EXISTS && state == OBJECT_EXISTS_CLEAN))
drivers/block/rbd.c:2092:23: note: 'current_state' was declared here
u8 state, new_state, current_state;
^~~~~~~~~~~~~

vim +/current_state +2124 drivers/block/rbd.c

2075
2076 /*
2077 * This function needs snap_id (or more precisely just something to
2078 * distinguish between HEAD and snapshot object maps), new_state and
2079 * current_state that were passed to rbd_object_map_update().
2080 *
2081 * To avoid allocating and stashing a context we piggyback on the OSD
2082 * request. A HEAD update has two ops (assert_locked). For new_state
2083 * and current_state we decode our own object_map_update op, encoded in
2084 * rbd_cls_object_map_update().
2085 */
2086 static int rbd_object_map_update_finish(struct rbd_obj_request *obj_req,
2087 struct ceph_osd_request *osd_req)
2088 {
2089 struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
2090 struct ceph_osd_data *osd_data;
2091 u64 objno;
2092 u8 state, new_state, current_state;
2093 bool has_current_state;
2094 void *p;
2095
2096 if (osd_req->r_result)
2097 return osd_req->r_result;
2098
2099 /*
2100 * Nothing to do for a snapshot object map.
2101 */
2102 if (osd_req->r_num_ops == 1)
2103 return 0;
2104
2105 /*
2106 * Update in-memory HEAD object map.
2107 */
2108 rbd_assert(osd_req->r_num_ops == 2);
2109 osd_data = osd_req_op_data(osd_req, 1, cls, request_data);
2110 rbd_assert(osd_data->type == CEPH_OSD_DATA_TYPE_PAGES);
2111
2112 p = page_address(osd_data->pages[0]);
2113 objno = ceph_decode_64(&p);
2114 rbd_assert(objno == obj_req->ex.oe_objno);
2115 rbd_assert(ceph_decode_64(&p) == objno + 1);
2116 new_state = ceph_decode_8(&p);
2117 has_current_state = ceph_decode_8(&p);
2118 if (has_current_state)
2119 current_state = ceph_decode_8(&p);
2120
2121 spin_lock(&rbd_dev->object_map_lock);
2122 state = __rbd_object_map_get(rbd_dev, objno);
2123 if (!has_current_state || current_state == state ||
> 2124 (current_state == OBJECT_EXISTS && state == OBJECT_EXISTS_CLEAN))
2125 __rbd_object_map_set(rbd_dev, objno, new_state);
2126 spin_unlock(&rbd_dev->object_map_lock);
2127
2128 return 0;
2129 }
2130

---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
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