I'm working on some new Smatch stuff and I hit the following problem
which I don't know how to fix.
drivers/usb/gadget/composite.c:1156 composite_setup()
warn: calling potential NULL 'f->set_alt()'
drivers/usb/gadget/composite.c
1143 /* function drivers must handle get/set altsetting; if there's
1144 * no get() method, we know only altsetting zero works.
The comment says we should check ->get.
1145 */
1146 case USB_REQ_SET_INTERFACE:
1147 if (ctrl->bRequestType != USB_RECIP_INTERFACE)
1148 goto unknown;
1149 if (!cdev->config || intf >= MAX_CONFIG_INTERFACES)
1150 break;
1151 f = cdev->config->interface[intf];
1152 if (!f)
1153 break;
1154 if (w_value && !f->set_alt)
^^^^^^^^^^
We used to check ->get_alt() until dd4dff8b03 "USB: composite: Fix bug:
should test set_alt function pointer before use it".
1155 break;
1156 value = f->set_alt(f, w_index, w_value);
If "w_value" is zero then ->set_alt() can be NULL leading to a NULL
dereference.
1157 if (value == USB_GADGET_DELAYED_STATUS) {
1158 DBG(cdev,
1159 "%s: interface %d (%s) requested delayed
status\n",
1160 __func__, intf, f->name);
1161 cdev->delayed_status++;
1162 DBG(cdev, "delayed_status count %d\n",
1163 cdev->delayed_status);
1164 }
1165 break;
regards,
dan carpenter
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