ata: libata-transport: fix error handling in ata_tport_add()

In ata_tport_add(), the return value of transport_add_device() is
not checked. As a result, it causes null-ptr-deref while removing
the module, because transport_remove_device() is called to remove
the device that was not added.

Unable to handle kernel NULL pointer dereference at virtual address 00000000000000d0
CPU: 12 PID: 13605 Comm: rmmod Kdump: loaded Tainted: G        W          6.1.0-rc3+ #8
pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : device_del+0x48/0x39c
lr : device_del+0x44/0x39c
Call trace:
 device_del+0x48/0x39c
 attribute_container_class_device_del+0x28/0x40
 transport_remove_classdev+0x60/0x7c
 attribute_container_device_trigger+0x118/0x120
 transport_remove_device+0x20/0x30
 ata_tport_delete+0x34/0x60 [libata]
 ata_port_detach+0x148/0x1b0 [libata]
 ata_pci_remove_one+0x50/0x80 [libata]
 ahci_remove_one+0x4c/0x8c [ahci]

Fix this by checking and handling return value of transport_add_device()
in ata_tport_add().

Fixes: d902747 ("[libata] Add ATA transport class")
Signed-off-by: Yang Yingliang <[email protected]>
Signed-off-by: Damien Le Moal <[email protected]>

Author: Yang Yingliang

drivers/ata/libata-transport.c

@@ -301,7 +301,9 @@ int ata_tport_add(struct device *parent,
 	pm_runtime_enable(dev);
 	pm_runtime_forbid(dev);
 
-	transport_add_device(dev);
+	error = transport_add_device(dev);
+	if (error)
+		goto tport_transport_add_err;
 	transport_configure_device(dev);
 
 	error = ata_tlink_add(&ap->link);
@@ -312,6 +314,7 @@ int ata_tport_add(struct device *parent,
 
  tport_link_err:
 	transport_remove_device(dev);
+ tport_transport_add_err:
 	device_del(dev);
 
  tport_err: