I got the following null-ptr-deref report while doing fault injection test:
BUG: kernel NULL pointer dereference, address: 0000000000000058
CPU: 2 PID: 278 Comm: 37-i2c-ds2482 Tainted: G B W N 6.1.0-rc3+
RIP: 0010:klist_put+0x2d/0xd0
Call Trace:
<TASK>
klist_remove+0xf1/0x1c0
device_release_driver_internal+0x196/0x210
bus_remove_device+0x1bd/0x240
device_add+0xd3d/0x1100
w1_add_master_device+0x476/0x490 [wire]
ds2482_probe+0x303/0x3e0 [ds2482]
This is how it happened:
w1_alloc_dev()
// The dev->driver is set to w1_master_driver.
memcpy(&dev->dev, device, sizeof(struct device));
device_add()
bus_add_device()
dpm_sysfs_add() // It fails, calls bus_remove_device.
// error path
bus_remove_device()
// The dev->driver is not null, but driver is not bound.
__device_release_driver()
klist_remove(&dev->p->knode_driver) <-- It causes null-ptr-deref.
// normal path
bus_probe_device() // It's not called yet.
device_bind_driver()
If dev->driver is set, in the error path after calling bus_add_device()
in device_add(), bus_remove_device() is called, then the device will be
detached from driver. But device_bind_driver() is not called yet, so it
causes null-ptr-deref while access the 'knode_driver'. To fix this, set
dev->driver to null in the error path before calling bus_remove_device().
Fixes: 57eee3d23e88 ("Driver core: Call device_pm_add() after bus_add_device() in device_add()")
Signed-off-by: Yang Yingliang <[email protected]>
---
drivers/base/core.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index d02501933467..e5c15061070b 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3551,6 +3551,7 @@ int device_add(struct device *dev)
device_pm_remove(dev);
dpm_sysfs_remove(dev);
DPMError:
+ dev->driver = NULL;
bus_remove_device(dev);
BusError:
device_remove_attrs(dev);
--
2.25.1