Hi Menglong, kernel test robot noticed the following build warnings: [auto build test WARNING on bpf-next/master] url: https://github.com/intel-lab-lkp/linux/commits/Menglong-Dong/bpf-add-function-hash-table-for-tracing-multi/20250703-203035 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master patch link: https://lore.kernel.org/r/20250703121521.1874196-2-dongml2%40chinatelecom.cn patch subject: [PATCH bpf-next v2 01/18] bpf: add function hash table for tracing-multi config: i386-randconfig-062-20250704 (https://download.01.org/0day-ci/archive/20250704/202507042321.HJfEZMgT-lkp@xxxxxxxxx/config) compiler: gcc-12 (Debian 12.2.0-14+deb12u1) 12.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250704/202507042321.HJfEZMgT-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/202507042321.HJfEZMgT-lkp@xxxxxxxxx/ sparse warnings: (new ones prefixed by >>) >> kernel/bpf/kfunc_md.c:14:23: sparse: sparse: symbol 'default_mds' was not declared. Should it be static? >> kernel/bpf/kfunc_md.c:21:43: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected struct kfunc_md_array [noderef] __rcu *[addressable] [toplevel] kfunc_mds @@ got struct kfunc_md_array * @@ kernel/bpf/kfunc_md.c:21:43: sparse: expected struct kfunc_md_array [noderef] __rcu *[addressable] [toplevel] kfunc_mds kernel/bpf/kfunc_md.c:21:43: sparse: got struct kfunc_md_array * >> kernel/bpf/kfunc_md.c:186:26: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct atomic_t const [usertype] *v @@ got struct atomic_t [noderef] __rcu * @@ kernel/bpf/kfunc_md.c:186:26: sparse: expected struct atomic_t const [usertype] *v kernel/bpf/kfunc_md.c:186:26: sparse: got struct atomic_t [noderef] __rcu * >> kernel/bpf/kfunc_md.c:111:32: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct kfunc_md_array *mds @@ got struct kfunc_md_array [noderef] __rcu *extern [addressable] [toplevel] kfunc_mds @@ kernel/bpf/kfunc_md.c:111:32: sparse: expected struct kfunc_md_array *mds kernel/bpf/kfunc_md.c:111:32: sparse: got struct kfunc_md_array [noderef] __rcu *extern [addressable] [toplevel] kfunc_mds >> kernel/bpf/kfunc_md.c:153:17: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct kfunc_md_array *old_mds @@ got struct kfunc_md_array [noderef] __rcu *extern [addressable] [toplevel] kfunc_mds @@ kernel/bpf/kfunc_md.c:153:17: sparse: expected struct kfunc_md_array *old_mds kernel/bpf/kfunc_md.c:153:17: sparse: got struct kfunc_md_array [noderef] __rcu *extern [addressable] [toplevel] kfunc_mds kernel/bpf/kfunc_md.c:194:26: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct atomic_t const [usertype] *v @@ got struct atomic_t [noderef] __rcu * @@ kernel/bpf/kfunc_md.c:194:26: sparse: expected struct atomic_t const [usertype] *v kernel/bpf/kfunc_md.c:194:26: sparse: got struct atomic_t [noderef] __rcu * >> kernel/bpf/kfunc_md.c:214:21: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct atomic_t [usertype] *v @@ got struct atomic_t [noderef] __rcu * @@ kernel/bpf/kfunc_md.c:214:21: sparse: expected struct atomic_t [usertype] *v kernel/bpf/kfunc_md.c:214:21: sparse: got struct atomic_t [noderef] __rcu * kernel/bpf/kfunc_md.c:238:30: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct atomic_t const [usertype] *v @@ got struct atomic_t [noderef] __rcu * @@ kernel/bpf/kfunc_md.c:238:30: sparse: expected struct atomic_t const [usertype] *v kernel/bpf/kfunc_md.c:238:30: sparse: got struct atomic_t [noderef] __rcu * >> kernel/bpf/kfunc_md.c:126:21: sparse: sparse: dereference of noderef expression kernel/bpf/kfunc_md.c:139:31: sparse: sparse: dereference of noderef expression kernel/bpf/kfunc_md.c:140:17: sparse: sparse: dereference of noderef expression kernel/bpf/kfunc_md.c:186:57: sparse: sparse: dereference of noderef expression kernel/bpf/kfunc_md.c:194:57: sparse: sparse: dereference of noderef expression kernel/bpf/kfunc_md.c:197:13: sparse: sparse: dereference of noderef expression kernel/bpf/kfunc_md.c:248:35: sparse: sparse: dereference of noderef expression kernel/bpf/kfunc_md.c:249:17: sparse: sparse: dereference of noderef expression vim +/default_mds +14 kernel/bpf/kfunc_md.c 12 13 #define MIN_KFUNC_MD_ARRAY_BITS 4 > 14 struct kfunc_md_array default_mds = { 15 .used = ATOMIC_INIT(0), 16 .hash_bits = MIN_KFUNC_MD_ARRAY_BITS, 17 .mds = { 18 [0 ... ((1 << MIN_KFUNC_MD_ARRAY_BITS) - 1)] = HLIST_HEAD_INIT, 19 }, 20 }; > 21 struct kfunc_md_array __rcu *kfunc_mds = &default_mds; 22 EXPORT_SYMBOL_GPL(kfunc_mds); 23 24 static DEFINE_MUTEX(kfunc_md_mutex); 25 26 static int kfunc_md_array_inc(void); 27 28 static void kfunc_md_release_rcu(struct rcu_head *rcu) 29 { 30 struct kfunc_md *md; 31 32 md = container_of(rcu, struct kfunc_md, rcu); 33 /* Step 4, free the md */ 34 kfree(md); 35 } 36 37 static void kfunc_md_release_rcu_tasks(struct rcu_head *rcu) 38 { 39 struct kfunc_md *md; 40 41 md = container_of(rcu, struct kfunc_md, rcu); 42 /* Step 3, wait for the nornal progs and bfp_global_caller to finish */ 43 call_rcu_tasks(&md->rcu, kfunc_md_release_rcu); 44 } 45 46 static void kfunc_md_release(struct percpu_ref *pcref) 47 { 48 struct kfunc_md *md; 49 50 md = container_of(pcref, struct kfunc_md, pcref); 51 percpu_ref_exit(&md->pcref); 52 53 /* Step 2, wait for sleepable progs to finish. */ 54 call_rcu_tasks_trace(&md->rcu, kfunc_md_release_rcu_tasks); 55 } 56 57 struct kfunc_md *kfunc_md_get(unsigned long ip) 58 { 59 struct kfunc_md_array *mds; 60 struct kfunc_md *md; 61 62 rcu_read_lock(); 63 mds = rcu_dereference(kfunc_mds); 64 md = __kfunc_md_get(mds, ip); 65 rcu_read_unlock(); 66 67 return md; 68 } 69 EXPORT_SYMBOL_GPL(kfunc_md_get); 70 71 static struct kfunc_md *__kfunc_md_create(struct kfunc_md_array *mds, unsigned long ip, 72 int nr_args) 73 { 74 struct kfunc_md *md = __kfunc_md_get(mds, ip); 75 int err; 76 77 if (md) { 78 md->users++; 79 return md; 80 } 81 82 md = kzalloc(sizeof(*md), GFP_KERNEL); 83 if (!md) 84 return NULL; 85 86 md->users = 1; 87 md->func = ip; 88 md->nr_args = nr_args; 89 90 err = percpu_ref_init(&md->pcref, kfunc_md_release, 0, GFP_KERNEL); 91 if (err) { 92 kfree(md); 93 return NULL; 94 } 95 96 hlist_add_head_rcu(&md->hash, kfunc_md_hash_head(mds, ip)); 97 atomic_inc(&mds->used); 98 99 return md; 100 } 101 102 struct kfunc_md *kfunc_md_create(unsigned long ip, int nr_args) 103 { 104 struct kfunc_md *md = NULL; 105 106 mutex_lock(&kfunc_md_mutex); 107 108 if (kfunc_md_array_inc()) 109 goto out; 110 > 111 md = __kfunc_md_create(kfunc_mds, ip, nr_args); 112 out: 113 mutex_unlock(&kfunc_md_mutex); 114 115 return md; 116 } 117 EXPORT_SYMBOL_GPL(kfunc_md_create); 118 119 static int kfunc_md_array_adjust(bool inc) 120 { 121 struct kfunc_md_array *new_mds, *old_mds; 122 struct kfunc_md *md, *new_md; 123 struct hlist_node *n; 124 int size, hash_bits, i; 125 > 126 hash_bits = kfunc_mds->hash_bits; 127 hash_bits += inc ? 1 : -1; 128 129 size = sizeof(*new_mds) + sizeof(struct hlist_head) * (1 << hash_bits); 130 new_mds = kmalloc(size, GFP_KERNEL | __GFP_ZERO); 131 if (!new_mds) 132 return -ENOMEM; 133 134 new_mds->hash_bits = hash_bits; 135 for (i = 0; i < (1 << new_mds->hash_bits); i++) 136 INIT_HLIST_HEAD(&new_mds->mds[i]); 137 138 /* copy all the mds from kfunc_mds to new_mds */ 139 for (i = 0; i < (1 << kfunc_mds->hash_bits); i++) { 140 hlist_for_each_entry(md, &kfunc_mds->mds[i], hash) { 141 new_md = __kfunc_md_create(new_mds, md->func, md->nr_args); 142 if (!new_md) 143 goto err_out; 144 145 new_md->bpf_prog_cnt = md->bpf_prog_cnt; 146 new_md->bpf_origin_call = md->bpf_origin_call; 147 new_md->users = md->users; 148 149 memcpy(new_md->bpf_progs, md->bpf_progs, sizeof(md->bpf_progs)); 150 } 151 } 152 > 153 old_mds = kfunc_mds; 154 rcu_assign_pointer(kfunc_mds, new_mds); 155 synchronize_rcu(); 156 157 /* free all the mds in the old_mds. See kfunc_md_put() for the 158 * complete release process. 159 */ 160 for (i = 0; i < (1 << old_mds->hash_bits); i++) { 161 hlist_for_each_entry_safe(md, n, &old_mds->mds[i], hash) { 162 percpu_ref_kill(&md->pcref); 163 hlist_del(&md->hash); 164 } 165 } 166 167 if (old_mds != &default_mds) 168 kfree_rcu(old_mds, rcu); 169 170 return 0; 171 172 err_out: 173 for (i = 0; i < (1 << new_mds->hash_bits); i++) { 174 hlist_for_each_entry_safe(md, n, &new_mds->mds[i], hash) { 175 percpu_ref_exit(&md->pcref); 176 hlist_del(&md->hash); 177 kfree(md); 178 } 179 } 180 return -ENOMEM; 181 } 182 183 static int kfunc_md_array_inc(void) 184 { 185 /* increase the hash table if greater than 90% */ > 186 if (atomic_read(&kfunc_mds->used) * 10 < (1 << (kfunc_mds->hash_bits)) * 9) 187 return 0; 188 return kfunc_md_array_adjust(true); 189 } 190 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
