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Message-ID: <201812061014.UpXttouc%fengguang.wu@intel.com>
Date: Thu, 6 Dec 2018 10:49:02 +0800
From: kbuild test robot <lkp@...el.com>
To: Jakub Audykowicz <jakub.audykowicz@...il.com>
Cc: kbuild-all@...org, linux-sctp@...r.kernel.org, vyasevich@...il.com,
nhorman@...driver.com, marcelo.leitner@...il.com,
davem@...emloft.net, netdev@...r.kernel.org,
Jakub Audykowicz <jakub.audykowicz@...il.com>
Subject: Re: [PATCH net] sctp: frag_point sanity check
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
---
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