Hi Jakub, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on net/master] url: https://github.com/0day-ci/linux/commits/Jakub-Audykowicz/sctp-frag_point-sanity-check/20181206-011917 config: x86_64-randconfig-x015-12051035 (attached as .config) compiler: gcc-7 (Debian 7.3.0-1) 7.3.0 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 All warnings (new ones prefixed by >>): In file included from include/linux/kernel.h:14:0, from net/sctp/chunk.c:36: net/sctp/chunk.c: In function 'sctp_datamsg_from_user': include/linux/kern_levels.h:5:18: warning: format '%d' expects argument of type 'int', but argument 4 has type 'size_t {aka long unsigned int}' [-Wformat=] #define KERN_SOH "\001" /* ASCII Start Of Header */ ^ include/linux/printk.h:429:10: note: in definition of macro 'printk_ratelimited' printk(fmt, ##__VA_ARGS__); \ ^~~ include/linux/kern_levels.h:12:22: note: in expansion of macro 'KERN_SOH' #define KERN_WARNING KERN_SOH "4" /* warning conditions */ ^~~~~~~~ include/linux/printk.h:445:21: note: in expansion of macro 'KERN_WARNING' printk_ratelimited(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__) ^~~~~~~~~~~~ >> net/sctp/chunk.c:197:3: note: in expansion of macro 'pr_warn_ratelimited' pr_warn_ratelimited("%s: asoc:%p frag_point is zero, forcing max_data to default minimum (%d)", ^~~~~~~~~~~~~~~~~~~ vim +/pr_warn_ratelimited +197 net/sctp/chunk.c 156 157 158 /* A data chunk can have a maximum payload of (2^16 - 20). Break 159 * down any such message into smaller chunks. Opportunistically, fragment 160 * the chunks down to the current MTU constraints. We may get refragmented 161 * later if the PMTU changes, but it is _much better_ to fragment immediately 162 * with a reasonable guess than always doing our fragmentation on the 163 * soft-interrupt. 164 */ 165 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, 166 struct sctp_sndrcvinfo *sinfo, 167 struct iov_iter *from) 168 { 169 size_t len, first_len, max_data, remaining; 170 size_t msg_len = iov_iter_count(from); 171 struct sctp_shared_key *shkey = NULL; 172 struct list_head *pos, *temp; 173 struct sctp_chunk *chunk; 174 struct sctp_datamsg *msg; 175 int err; 176 177 msg = sctp_datamsg_new(GFP_KERNEL); 178 if (!msg) 179 return ERR_PTR(-ENOMEM); 180 181 /* Note: Calculate this outside of the loop, so that all fragments 182 * have the same expiration. 183 */ 184 if (asoc->peer.prsctp_capable && sinfo->sinfo_timetolive && 185 (SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags) || 186 !SCTP_PR_POLICY(sinfo->sinfo_flags))) 187 msg->expires_at = jiffies + 188 msecs_to_jiffies(sinfo->sinfo_timetolive); 189 190 /* This is the biggest possible DATA chunk that can fit into 191 * the packet 192 */ 193 max_data = asoc->frag_point; 194 if (unlikely(!max_data)) { 195 max_data = sctp_min_frag_point(sctp_sk(asoc->base.sk), 196 sctp_datachk_len(&asoc->stream)); > 197 pr_warn_ratelimited("%s: asoc:%p frag_point is zero, forcing max_data to default minimum (%d)", 198 __func__, asoc, max_data); 199 } 200 201 /* If the the peer requested that we authenticate DATA chunks 202 * we need to account for bundling of the AUTH chunks along with 203 * DATA. 204 */ 205 if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) { 206 struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc); 207 208 if (hmac_desc) 209 max_data -= SCTP_PAD4(sizeof(struct sctp_auth_chunk) + 210 hmac_desc->hmac_len); 211 212 if (sinfo->sinfo_tsn && 213 sinfo->sinfo_ssn != asoc->active_key_id) { 214 shkey = sctp_auth_get_shkey(asoc, sinfo->sinfo_ssn); 215 if (!shkey) { 216 err = -EINVAL; 217 goto errout; 218 } 219 } else { 220 shkey = asoc->shkey; 221 } 222 } 223 224 /* Set first_len and then account for possible bundles on first frag */ 225 first_len = max_data; 226 227 /* Check to see if we have a pending SACK and try to let it be bundled 228 * with this message. Do this if we don't have any data queued already. 229 * To check that, look at out_qlen and retransmit list. 230 * NOTE: we will not reduce to account for SACK, if the message would 231 * not have been fragmented. 232 */ 233 if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) && 234 asoc->outqueue.out_qlen == 0 && 235 list_empty(&asoc->outqueue.retransmit) && 236 msg_len > max_data) 237 first_len -= SCTP_PAD4(sizeof(struct sctp_sack_chunk)); 238 239 /* Encourage Cookie-ECHO bundling. */ 240 if (asoc->state < SCTP_STATE_COOKIE_ECHOED) 241 first_len -= SCTP_ARBITRARY_COOKIE_ECHO_LEN; 242 243 /* Account for a different sized first fragment */ 244 if (msg_len >= first_len) { 245 msg->can_delay = 0; 246 if (msg_len > first_len) 247 SCTP_INC_STATS(sock_net(asoc->base.sk), 248 SCTP_MIB_FRAGUSRMSGS); 249 } else { 250 /* Which may be the only one... */ 251 first_len = msg_len; 252 } 253 254 /* Create chunks for all DATA chunks. */ 255 for (remaining = msg_len; remaining; remaining -= len) { 256 u8 frag = SCTP_DATA_MIDDLE_FRAG; 257 258 if (remaining == msg_len) { 259 /* First frag, which may also be the last */ 260 frag |= SCTP_DATA_FIRST_FRAG; 261 len = first_len; 262 } else { 263 /* Middle frags */ 264 len = max_data; 265 } 266 267 if (len >= remaining) { 268 /* Last frag, which may also be the first */ 269 len = remaining; 270 frag |= SCTP_DATA_LAST_FRAG; 271 272 /* The application requests to set the I-bit of the 273 * last DATA chunk of a user message when providing 274 * the user message to the SCTP implementation. 275 */ 276 if ((sinfo->sinfo_flags & SCTP_EOF) || 277 (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY)) 278 frag |= SCTP_DATA_SACK_IMM; 279 } 280 281 chunk = asoc->stream.si->make_datafrag(asoc, sinfo, len, frag, 282 GFP_KERNEL); 283 if (!chunk) { 284 err = -ENOMEM; 285 goto errout; 286 } 287 288 err = sctp_user_addto_chunk(chunk, len, from); 289 if (err < 0) 290 goto errout_chunk_free; 291 292 chunk->shkey = shkey; 293 294 /* Put the chunk->skb back into the form expected by send. */ 295 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr - 296 chunk->skb->data); 297 298 sctp_datamsg_assign(msg, chunk); 299 list_add_tail(&chunk->frag_list, &msg->chunks); 300 } 301 302 return msg; 303 304 errout_chunk_free: 305 sctp_chunk_free(chunk); 306 307 errout: 308 list_for_each_safe(pos, temp, &msg->chunks) { 309 list_del_init(pos); 310 chunk = list_entry(pos, struct sctp_chunk, frag_list); 311 sctp_chunk_free(chunk); 312 } 313 sctp_datamsg_put(msg); 314 315 return ERR_PTR(err); 316 } 317 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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