On Sat, 23 Oct 2021, Michael Zaidman wrote: > The below scenario causes the kernel NULL pointer dereference failure: > 1. sudo insmod hid-ft260.ko > 2. sudo modprobe lm75 > 3. unplug USB hid-ft260 > 4. plug USB hid-ft260 > > [ +0.000006] Call Trace: > [ +0.000004] __i2c_smbus_xfer.part.0+0xd1/0x310 > [ +0.000007] ? ft260_smbus_write+0x140/0x140 [hid_ft260] > [ +0.000005] __i2c_smbus_xfer+0x2b/0x80 > [ +0.000004] i2c_smbus_xfer+0x61/0xf0 > [ +0.000005] i2c_default_probe+0xf9/0x130 > [ +0.000004] i2c_detect_address+0x84/0x160 > [ +0.000004] ? kmem_cache_alloc_trace+0xf6/0x200 > [ +0.000009] ? i2c_detect.isra.0+0x69/0x130 > [ +0.000005] i2c_detect.isra.0+0xbf/0x130 > [ +0.000004] ? __process_new_driver+0x30/0x30 > [ +0.000004] __process_new_adapter+0x18/0x20 > [ +0.000004] bus_for_each_drv+0x84/0xd0 > [ +0.000003] i2c_register_adapter+0x1e4/0x400 > [ +0.000005] i2c_add_adapter+0x5c/0x80 > [ +0.000004] ft260_probe.cold+0x222/0x2e2 [hid_ft260] > [ +0.000006] hid_device_probe+0x10e/0x170 [hid] > [ +0.000009] really_probe+0xff/0x460 > [ +0.000004] driver_probe_device+0xe9/0x160 > [ +0.000003] __device_attach_driver+0x71/0xd0 > [ +0.000004] ? driver_allows_async_probing+0x50/0x50 > [ +0.000004] bus_for_each_drv+0x84/0xd0 > [ +0.000002] __device_attach+0xde/0x1e0 > [ +0.000004] device_initial_probe+0x13/0x20 > [ +0.000004] bus_probe_device+0x8f/0xa0 > [ +0.000003] device_add+0x333/0x5f0 > > It happened when i2c core probed for the devices associated with the lm75 > driver by invoking 2c_detect()-->..-->ft260_smbus_write() from within the > ft260_probe before setting the adapter data with i2c_set_adapdata(). > > Moving the i2c_set_adapdata() before i2c_add_adapter() fixed the failure. > > Signed-off-by: Michael Zaidman <michael.zaidman@xxxxxxxxx> > Signed-off-by: Germain Hebert <germain.hebert@xxxxxxxxxx> Applied, thanks. -- Jiri Kosina SUSE Labs
