Bug 188931
| Summary: | Function hfc4s8s_probe() does not set error code when the call to request_region() fails | ||
|---|---|---|---|
| Product: | Drivers | Reporter: | bianpan (bianpan2010) |
| Component: | ISDN | Assignee: | drivers_isdn |
| Status: | RESOLVED CODE_FIX | ||
| Severity: | normal | ||
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | linux-4.9-rc6 | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
| Attachments: | The patch fixes the bug | ||
Created attachment 256437 [details]
The patch fixes the bug
The patch has been merged into the latest version of the Linux kernel. So I will close the bug.
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Function request_region() returns a NULL pointer on failures. In the function hfc4s8s_probe() defined in file drivers/isdn/hisax/hfc4s8s_l1.c, it is called and its return value is checked against NULL. When the return value is NULL, the control flow jumps to label "out" and returns variable err. However, the value of variable err is 0. The check of err at line 1484 guarantees that the value of err must be 0 when request_region() is called. As a result, hfc4s8s_probe() will return 0 (indicates success) even if request_region() fails. Maybe it is better to explicitly assign "-ENOMEM" to err when request_region() returns a NULL pointer. Codes and comments related to this bug are summarised as below. hfc4s8s_probe @@ drivers/isdn/hisax/hfc4s8s_l1.c 1469 static int 1470 hfc4s8s_probe(struct pci_dev *pdev, const struct pci_device_id *ent) 1471 { 1472 int err = -ENOMEM; ... 1482 err = pci_enable_device(pdev); 1483 1484 if (err) 1485 goto out; ... 1498 if (!request_region(hw->iobase, 8, hw->card_name)) { 1499 printk(KERN_INFO 1500 "HFC-4S/8S: failed to request address space at 0x%04x\n", 1501 hw->iobase); // insert "err = -ENOMEM;" here? 1502 goto out; 1503 } ... 1511 out: 1512 kfree(hw); 1513 return (err); 1514 } Thanks very much!