fs/proc/proc_net.c:130: warning: Function parameter or member 'state_size' not described in 'proc_create_net_data_write'
From: kernel test robot
Date: Tue Nov 21 2023 - 03:22:29 EST
Hi David,
FYI, the error/warning still remains.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 98b1cc82c4affc16f5598d4fa14b1858671b2263
commit: 564def71765caf65040f926c0783b9c27cc6c087 proc: Add a way to make network proc files writable
date: 6 years ago
config: x86_64-buildonly-randconfig-001-20231012 (https://download.01.org/0day-ci/archive/20231121/202311211605.jYnwq7JO-lkp@xxxxxxxxx/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231121/202311211605.jYnwq7JO-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/202311211605.jYnwq7JO-lkp@xxxxxxxxx/
All warnings (new ones prefixed by >>):
In file included from arch/x86/include/asm/bug.h:83,
from include/linux/bug.h:5,
from include/linux/thread_info.h:12,
from arch/x86/include/asm/preempt.h:7,
from include/linux/preempt.h:81,
from include/linux/rcupdate.h:40,
from include/linux/rculist.h:11,
from include/linux/pid.h:5,
from include/linux/sched.h:14,
from include/linux/uaccess.h:5,
from fs/proc/proc_net.c:11:
fs/proc/proc_net.c: In function 'seq_open_net':
fs/proc/proc_net.c:47:33: warning: comparison is always false due to limited range of data type [-Wtype-limits]
47 | WARN_ON_ONCE(state_size < sizeof(*p));
| ^
include/asm-generic/bug.h:69:32: note: in definition of macro 'WARN_ON_ONCE'
69 | int __ret_warn_on = !!(condition); \
| ^~~~~~~~~
>> fs/proc/proc_net.c:130: warning: Function parameter or member 'state_size' not described in 'proc_create_net_data_write'
vim +130 fs/proc/proc_net.c
> 11 #include <linux/uaccess.h>
12
13 #include <linux/errno.h>
14 #include <linux/time.h>
15 #include <linux/proc_fs.h>
16 #include <linux/stat.h>
17 #include <linux/slab.h>
18 #include <linux/init.h>
19 #include <linux/sched.h>
20 #include <linux/sched/task.h>
21 #include <linux/module.h>
22 #include <linux/bitops.h>
23 #include <linux/mount.h>
24 #include <linux/nsproxy.h>
25 #include <linux/uidgid.h>
26 #include <net/net_namespace.h>
27 #include <linux/seq_file.h>
28
29 #include "internal.h"
30
31 static inline struct net *PDE_NET(struct proc_dir_entry *pde)
32 {
33 return pde->parent->data;
34 }
35
36 static struct net *get_proc_net(const struct inode *inode)
37 {
38 return maybe_get_net(PDE_NET(PDE(inode)));
39 }
40
41 static int seq_open_net(struct inode *inode, struct file *file)
42 {
43 unsigned int state_size = PDE(inode)->state_size;
44 struct seq_net_private *p;
45 struct net *net;
46
47 WARN_ON_ONCE(state_size < sizeof(*p));
48
49 if (file->f_mode & FMODE_WRITE && !PDE(inode)->write)
50 return -EACCES;
51
52 net = get_proc_net(inode);
53 if (!net)
54 return -ENXIO;
55
56 p = __seq_open_private(file, PDE(inode)->seq_ops, state_size);
57 if (!p) {
58 put_net(net);
59 return -ENOMEM;
60 }
61 #ifdef CONFIG_NET_NS
62 p->net = net;
63 #endif
64 return 0;
65 }
66
67 static int seq_release_net(struct inode *ino, struct file *f)
68 {
69 struct seq_file *seq = f->private_data;
70
71 put_net(seq_file_net(seq));
72 seq_release_private(ino, f);
73 return 0;
74 }
75
76 static const struct file_operations proc_net_seq_fops = {
77 .open = seq_open_net,
78 .read = seq_read,
79 .write = proc_simple_write,
80 .llseek = seq_lseek,
81 .release = seq_release_net,
82 };
83
84 struct proc_dir_entry *proc_create_net_data(const char *name, umode_t mode,
85 struct proc_dir_entry *parent, const struct seq_operations *ops,
86 unsigned int state_size, void *data)
87 {
88 struct proc_dir_entry *p;
89
90 p = proc_create_reg(name, mode, &parent, data);
91 if (!p)
92 return NULL;
93 p->proc_fops = &proc_net_seq_fops;
94 p->seq_ops = ops;
95 p->state_size = state_size;
96 return proc_register(parent, p);
97 }
98 EXPORT_SYMBOL_GPL(proc_create_net_data);
99
100 /**
101 * proc_create_net_data_write - Create a writable net_ns-specific proc file
102 * @name: The name of the file.
103 * @mode: The file's access mode.
104 * @parent: The parent directory in which to create.
105 * @ops: The seq_file ops with which to read the file.
106 * @write: The write method which which to 'modify' the file.
107 * @data: Data for retrieval by PDE_DATA().
108 *
109 * Create a network namespaced proc file in the @parent directory with the
110 * specified @name and @mode that allows reading of a file that displays a
111 * series of elements and also provides for the file accepting writes that have
112 * some arbitrary effect.
113 *
114 * The functions in the @ops table are used to iterate over items to be
115 * presented and extract the readable content using the seq_file interface.
116 *
117 * The @write function is called with the data copied into a kernel space
118 * scratch buffer and has a NUL appended for convenience. The buffer may be
119 * modified by the @write function. @write should return 0 on success.
120 *
121 * The @data value is accessible from the @show and @write functions by calling
122 * PDE_DATA() on the file inode. The network namespace must be accessed by
123 * calling seq_file_net() on the seq_file struct.
124 */
125 struct proc_dir_entry *proc_create_net_data_write(const char *name, umode_t mode,
126 struct proc_dir_entry *parent,
127 const struct seq_operations *ops,
128 proc_write_t write,
129 unsigned int state_size, void *data)
> 130 {
131 struct proc_dir_entry *p;
132
133 p = proc_create_reg(name, mode, &parent, data);
134 if (!p)
135 return NULL;
136 p->proc_fops = &proc_net_seq_fops;
137 p->seq_ops = ops;
138 p->state_size = state_size;
139 p->write = write;
140 return proc_register(parent, p);
141 }
142 EXPORT_SYMBOL_GPL(proc_create_net_data_write);
143
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