[PATCH] xen/pciback: Prevent NULL pointer dereference in quirks_show

[Stefan Nuernberger]

From: Uwe Dannowski <uwed@xxxxxxxxx>

Reading /sys/bus/pci/drivers/pciback/quirks while unbinding can result
in dereferencing a NULL pointer. Instead, skip printing information
about the dangling quirk.

Reported-by: Conny Seidel <consei@xxxxxxxxx>
Signed-off-by: Uwe Dannowski <uwed@xxxxxxxxx>
Signed-off-by: Stefan Nuernberger <snu@xxxxxxxxxx>

Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
---
 drivers/xen/xen-pciback/pci_stub.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
index 097410a7cdb7..da725e474294 100644
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -1346,6 +1346,8 @@ static ssize_t quirks_show(struct device_driver *drv, char *buf)
 				   quirk->devid.subdevice);
 
 		dev_data = pci_get_drvdata(quirk->pdev);
+		if (!dev_data)
+			continue;
 
 		list_for_each_entry(cfg_entry, &dev_data->config_fields, list) {
 			field = cfg_entry->field;
-- 
2.23.0




Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879