[congwang:sch_bpf 2/3] net/sched/sch_bpf.c:185:21: error: called object type 'int' is not a function or function pointer

From: kernel test robot
Date: Sat Sep 04 2021 - 19:04:17 EST

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tree: https://github.com/congwang/linux.git sch_bpf
head: f680855badd6d78b73490b5785ed3de5d68bf26b
commit: ac00415a225e3cbd2c3a7fd5f38dacdfadfcc1ac [2/3] net_sched: introduce eBPF based Qdisc
config: hexagon-buildonly-randconfig-r004-20210905 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 6fe2beba7d2a41964af658c8c59dd172683ef739)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/congwang/linux/commit/ac00415a225e3cbd2c3a7fd5f38dacdfadfcc1ac
git remote add congwang https://github.com/congwang/linux.git
git fetch --no-tags congwang sch_bpf
git checkout ac00415a225e3cbd2c3a7fd5f38dacdfadfcc1ac
# save the attached .config to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross O=build_dir ARCH=hexagon SHELL=/bin/bash net/sched/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All error/warnings (new ones prefixed by >>):

>> net/sched/sch_bpf.c:144:6: warning: variable 'cl' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
if (result >= 0) {
^~~~~~~~~~~~
net/sched/sch_bpf.c:164:9: note: uninitialized use occurs here
return cl;
^~
net/sched/sch_bpf.c:144:2: note: remove the 'if' if its condition is always true
if (result >= 0) {
^~~~~~~~~~~~~~~~~~
net/sched/sch_bpf.c:134:26: note: initialize the variable 'cl' to silence this warning
struct sch_bpf_class *cl;
^
= NULL
>> net/sched/sch_bpf.c:185:21: error: called object type 'int' is not a function or function pointer
res = BPF_PROG_RUN(enqueue, &ctx);
~~~~~~~~~~~~^
net/sched/sch_bpf.c:254:20: error: called object type 'int' is not a function or function pointer
res = BPF_PROG_RUN(dequeue, &ctx);
~~~~~~~~~~~~^
>> net/sched/sch_bpf.c:256:10: error: incompatible pointer types returning 'struct __sk_buff *' from a function with result type 'struct sk_buff *' [-Werror,-Wincompatible-pointer-types]
return ctx.skb;
^~~~~~~
net/sched/sch_bpf.c:525:24: warning: unused variable 'q' [-Wunused-variable]
struct sch_bpf_qdisc *q = qdisc_priv(sch);
^
2 warnings and 3 errors generated.

vim +/int +185 net/sched/sch_bpf.c

130
131 static struct sch_bpf_class *sch_bpf_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
132 {
133 struct sch_bpf_qdisc *q = qdisc_priv(sch);
134 struct sch_bpf_class *cl;
135 struct tcf_proto *tcf;
136 struct tcf_result res;
137 int result;
138
139 tcf = rcu_dereference_bh(q->filter_list);
140 if (!tcf)
141 return NULL;
142 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
143 result = tcf_classify(skb, NULL, tcf, &res, false);
> 144 if (result >= 0) {
145 #ifdef CONFIG_NET_CLS_ACT
146 switch (result) {
147 case TC_ACT_QUEUED:
148 case TC_ACT_STOLEN:
149 case TC_ACT_TRAP:
150 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
151 fallthrough;
152 case TC_ACT_SHOT:
153 return NULL;
154 }
155 #endif
156 cl = (void *)res.class;
157 if (!cl) {
158 cl = sch_bpf_find(sch, res.classid);
159 if (!cl)
160 return NULL;
161 }
162 }
163
164 return cl;
165 }
166
167 static int sch_bpf_enqueue(struct sk_buff *skb, struct Qdisc *sch,
168 struct sk_buff **to_free)
169 {
170 struct sch_bpf_qdisc *q = qdisc_priv(sch);
171 unsigned int len = qdisc_pkt_len(skb);
172 struct sch_bpf_ctx ctx = {};
173 struct sch_bpf_class *cl;
174 int res = NET_XMIT_SUCCESS;
175
176 cl = sch_bpf_classify(skb, sch, &res);
177 if (!cl) {
178 struct bpf_prog *enqueue;
179
180 enqueue = rcu_dereference(q->enqueue_prog.prog);
181 bpf_compute_data_pointers(skb);
182
183 ctx.skb = (struct __sk_buff *)skb;
184 ctx.nr_flows = q->clhash.hashelems;
> 185 res = BPF_PROG_RUN(enqueue, &ctx);
186 if (q->direct)
187 return res;
188 switch (res) {
189 case SCH_BPF_DROP:
190 __qdisc_drop(skb, to_free);
191 return NET_XMIT_DROP;
192 }
193 cl = sch_bpf_find(sch, ctx.classid);
194 if (!cl) {
195 if (res & __NET_XMIT_BYPASS)
196 qdisc_qstats_drop(sch);
197 __qdisc_drop(skb, to_free);
198 return res;
199 }
200 }
201
202 if (cl->qdisc) {
203 res = qdisc_enqueue(skb, cl->qdisc, to_free);
204 if (res != NET_XMIT_SUCCESS) {
205 if (net_xmit_drop_count(res)) {
206 qdisc_qstats_drop(sch);
207 cl->drops++;
208 }
209 return res;
210 }
211 } else {
212 sch_bpf_skb_cb(skb)->rank = ctx.rank;
213 pq_push(&cl->pq, &skb->pqnode);
214 }
215
216 sch->qstats.backlog += len;
217 sch->q.qlen++;
218 return res;
219 }
220
221 static struct sk_buff *sch_bpf_dequeue(struct Qdisc *sch)
222 {
223 struct sch_bpf_qdisc *q = qdisc_priv(sch);
224 struct sk_buff *skb, *ret = NULL;
225 struct sch_bpf_ctx ctx = {};
226 struct bpf_prog *dequeue;
227 struct sch_bpf_class *cl;
228 struct pq_node *flow;
229 s64 now;
230 int res;
231
232 requeue:
233 flow = pq_pop(&q->flows);
234 if (!flow)
235 return NULL;
236
237 cl = container_of(flow, struct sch_bpf_class, node);
238 if (cl->qdisc) {
239 skb = cl->qdisc->dequeue(cl->qdisc);
240 ctx.classid = cl->common.classid;
241 } else {
242 struct pq_node *p = pq_pop(&cl->pq);
243
244 if (!p)
245 return NULL;
246 skb = container_of(p, struct sk_buff, pqnode);
247 ctx.classid = cl->rank;
248 }
249 ctx.skb = (struct __sk_buff *) skb;
250 ctx.nr_flows = q->clhash.hashelems;
251
252 dequeue = rcu_dereference(q->dequeue_prog.prog);
253 bpf_compute_data_pointers(skb);
254 res = BPF_PROG_RUN(dequeue, &ctx);
255 if (q->direct)
> 256 return ctx.skb;
257 switch (res) {
258 case SCH_BPF_OK:
259 ret = skb;
260 break;
261 case SCH_BPF_REQUEUE:
262 sch_bpf_skb_cb(skb)->rank = ctx.rank;
263 cl->rank = ctx.classid;
264 pq_push(&cl->pq, &skb->pqnode);
265 bstats_update(&cl->bstats, skb);
266 pq_push(&q->flows, &cl->node);
267 goto requeue;
268 case SCH_BPF_THROTTLE:
269 now = ktime_get_ns();
270 qdisc_watchdog_schedule_ns(&q->watchdog, now + ctx.delay);
271 qdisc_qstats_overlimit(sch);
272 cl->overlimits++;
273 return NULL;
274 default:
275 kfree_skb(skb);
276 ret = NULL;
277 }
278
279 if (pq_top(&cl->pq))
280 pq_push(&q->flows, &cl->node);
281 return ret;
282 }
283

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

Attachment: .config.gz
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Next message: Yury Norov: "[PATCH 0/2] lib: add sputchar() helper"
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