Hello Jeff Layton,
The patch d20c11d86d8f: "nfsd: Protect session creation and client
confirm using client_lock" from Jul 30, 2014, leads to the following
Smatch static checker warning:
net/sunrpc/addr.c:178 rpc_parse_scope_id()
warn: sleeping in atomic context
net/sunrpc/addr.c
161 static int rpc_parse_scope_id(struct net *net, const char *buf,
162 const size_t buflen, const char *delim,
163 struct sockaddr_in6 *sin6)
164 {
165 char *p;
166 size_t len;
167
168 if ((buf + buflen) == delim)
169 return 1;
170
171 if (*delim != IPV6_SCOPE_DELIMITER)
172 return 0;
173
174 if (!(ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL))
175 return 0;
176
177 len = (buf + buflen) - delim - 1;
--> 178 p = kmemdup_nul(delim + 1, len, GFP_KERNEL);
179 if (p) {
180 u32 scope_id = 0;
181 struct net_device *dev;
182
183 dev = dev_get_by_name(net, p);
184 if (dev != NULL) {
185 scope_id = dev->ifindex;
186 dev_put(dev);
187 } else {
188 if (kstrtou32(p, 10, &scope_id) != 0) {
189 kfree(p);
190 return 0;
191 }
192 }
193
194 kfree(p);
195
196 sin6->sin6_scope_id = scope_id;
197 return 1;
198 }
199
200 return 0;
201 }
The call tree is:
nfsd4_setclientid() <- disables preempt
-> gen_callback()
-> rpc_uaddr2sockaddr()
-> rpc_pton()
-> rpc_pton6()
-> rpc_parse_scope_id()
The commit added a spin_lock to nfsd4_setclientid().
fs/nfsd/nfs4state.c
4023 trace_nfsd_clid_verf_mismatch(conf, rqstp,
4024 &clverifier);
4025 } else
4026 trace_nfsd_clid_fresh(new);
4027 new->cl_minorversion = 0;
4028 gen_callback(new, setclid, rqstp);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
4029 add_to_unconfirmed(new);
4030 setclid->se_clientid.cl_boot = new->cl_clientid.cl_boot;
4031 setclid->se_clientid.cl_id = new->cl_clientid.cl_id;
4032 memcpy(setclid->se_confirm.data, new->cl_confirm.data, sizeof(setclid->se_confirm.data));
4033 new = NULL;
4034 status = nfs_ok;
4035 out:
4036 spin_unlock(&nn->client_lock);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This is the new lock.
4037 if (new)
4038 free_client(new);
4039 if (unconf) {
4040 trace_nfsd_clid_expire_unconf(&unconf->cl_clientid);
4041 expire_client(unconf);
4042 }
4043 return status;
regards,
dan carpenter
