New: Function twl_probe() does not set error codes on some failures

https://bugzilla.kernel.org/show_bug.cgi?id=189001

Bug ID: 189001
Summary: Function twl_probe() does not set error codes on some
failures
Product: SCSI Drivers
Version: 2.5
Kernel Version: linux-4.9-rc6
Hardware: All
OS: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: Other
Assignee: [email protected]
Reporter: [email protected]
Regression: No

In function twl_probe() defined in file drivers/scsi/3w-sas.c, because variable retval is checked at line 1608, its value must be 0 when pci_iomap() is called (at line 1614). If pci_iomap() returns a NULL pointer, the control flow jumps to label "out_release_mem_region", cleans and returns the value of retval (i.e. 0). As a result, function twl_probe() returns 0 (indicates success) even if there are errors. The behavior of its caller may be misled.
There are other 2 similar bugs when the function calls fail at lines 1601 and 1624. Though these errors may occur rarely, I think it is better to set the correct error codes on failures. Codes are summarised as follows.

twl_probe @@ drivers/scsi/3w-sas.c
1564 static int twl_probe(struct pci_dev *pdev, const struct pci_device_id *dev_id)
1565 {

1566     struct Scsi_Host *host = NULL;
1567     TW_Device_Extension *tw_dev;
1568     int retval = -ENODEV;
1569     int *ptr_phycount, phycount=0;

1570
1571 retval = pci_enable_device(pdev);
1572 if (retval) {
1573 TW_PRINTK(host, TW_DRIVER, 0x17, "Failed to enable pci device");
1574 goto out_disable_device;
1575 }

         ...
1601     if (twl_initialize_device_extension(tw_dev)) {
1602         TW_PRINTK(tw_dev->host, TW_DRIVER, 0x1a, "Failed to initialize
device extension");
             // Bug (1): retval takes value 0. Insert "retval = -ENODEV;"?
1603         goto out_free_device_extension;
1604     }
1605 
1606     /* Request IO regions */
1607     retval = pci_request_regions(pdev, "3w-sas");
1608     if (retval) {

1609 TW_PRINTK(tw_dev->host, TW_DRIVER, 0x1b, "Failed to get mem
region");
1610 goto out_free_device_extension;
1611 }
1612

1613     /* Save base address, use region 1 */
1614     tw_dev->base_addr = pci_iomap(pdev, 1, 0);
1615     if (!tw_dev->base_addr) {
1616         TW_PRINTK(tw_dev->host, TW_DRIVER, 0x1c, "Failed to ioremap");
             // Bug (2): retval takes value 0. Insert "retval = -ENOMEM;"?

1617 goto out_release_mem_region;
1618 }
1619
1620 /* Disable interrupts on the card */
1621 TWL_MASK_INTERRUPTS(tw_dev);
1622
1623 /* Initialize the card */
1624 if (twl_reset_sequence(tw_dev, 0)) {
1625 TW_PRINTK(tw_dev->host, TW_DRIVER, 0x1d, "Controller reset failed

during probe");
             // Bug (3): retval takes value 0. Insert "retval = -ENODEV;"?

1626 goto out_iounmap;
1627 }

Thanks very much!

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