Hi Dan,
Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
Hello Kai-Heng Feng,
This is a semi-automatic email about new static checker warnings.
I ran Smatch but didn't see the error message:
$ make -j`nproc` CHECK="~/smatch/smatch -p=kernel" C=1 bzImage modules |
tee warns.txt`"
Also, "val" will never get passed as null in quirks_param_set() by the
.set() caller, so it's actually superfluous.
Kai-Heng
The patch 027bd6cafd9a: "usb: core: Add "quirks" parameter for
usbcore" from Mar 20, 2018, leads to the following Smatch complaint:
drivers/usb/core/quirks.c:136 quirks_param_set()
error: we previously assumed 'val' could be null (see line 37)
drivers/usb/core/quirks.c
36
37 if (!val || !*val) {
^^^^
Patch adds check for NULL
38 quirk_count = 0;
39 kfree(quirk_list);
40 quirk_list = NULL;
41 goto unlock;
42 }
43
44 for (quirk_count = 1, i = 0; val[i]; i++)
45 if (val[i] == ',')
46 quirk_count++;
47
48 if (quirk_list) {
49 kfree(quirk_list);
50 quirk_list = NULL;
51 }
52
53 quirk_list = kcalloc(quirk_count, sizeof(struct quirk_entry),
54 GFP_KERNEL);
55 if (!quirk_list) {
56 mutex_unlock(&quirk_mutex);
57 return -ENOMEM;
58 }
59
60 for (i = 0, p = (char *)val; p && *p;) {
61 /* Each entry consists of VID:PID:flags */
62 field = strsep(&p, ":");
63 if (!field)
64 break;
65
66 if (kstrtou16(field, 16, &vid))
67 break;
68
69 field = strsep(&p, ":");
70 if (!field)
71 break;
72
73 if (kstrtou16(field, 16, &pid))
74 break;
75
76 field = strsep(&p, ",");
77 if (!field || !*field)
78 break;
79
80 /* Collect the flags */
81 for (flags = 0; *field; field++) {
82 switch (*field) {
83 case 'a':
84 flags |= USB_QUIRK_STRING_FETCH_255;
85 break;
86 case 'b':
87 flags |= USB_QUIRK_RESET_RESUME;
88 break;
89 case 'c':
90 flags |= USB_QUIRK_NO_SET_INTF;
91 break;
92 case 'd':
93 flags |= USB_QUIRK_CONFIG_INTF_STRINGS;
94 break;
95 case 'e':
96 flags |= USB_QUIRK_RESET;
97 break;
98 case 'f':
99 flags |= USB_QUIRK_HONOR_BNUMINTERFACES;
100 break;
101 case 'g':
102 flags |= USB_QUIRK_DELAY_INIT;
103 break;
104 case 'h':
105 flags |= USB_QUIRK_LINEAR_UFRAME_INTR_BINTERVAL;
106 break;
107 case 'i':
108 flags |= USB_QUIRK_DEVICE_QUALIFIER;
109 break;
110 case 'j':
111 flags |= USB_QUIRK_IGNORE_REMOTE_WAKEUP;
112 break;
113 case 'k':
114 flags |= USB_QUIRK_NO_LPM;
115 break;
116 case 'l':
117 flags |= USB_QUIRK_LINEAR_FRAME_INTR_BINTERVAL;
118 break;
119 case 'm':
120 flags |= USB_QUIRK_DISCONNECT_SUSPEND;
121 break;
122 /* Ignore unrecognized flag characters */
123 }
124 }
125
126 quirk_list[i++] = (struct quirk_entry)
127 { .vid = vid, .pid = pid, .flags = flags };
128 }
129
130 if (i < quirk_count)
131 quirk_count = i;
132
133 unlock:
134 mutex_unlock(&quirk_mutex);
135
136 return param_set_copystring(val, kp);
^^^
Patch adds new dereference (inside the function).
137 }
138
regards,
dan carpenter
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