commit bc8acc214d upstream.
async_complete() in uss720.c is a completion handler function for the
USB driver. So it should not sleep, but it is can sleep according to the
function call paths (from bottom to top) in Linux-4.16.
[FUNC] set_1284_register(GFP_KERNEL)
drivers/usb/misc/uss720.c, 372:
set_1284_register in parport_uss720_frob_control
drivers/parport/ieee1284.c, 560:
[FUNC_PTR]parport_uss720_frob_control in parport_ieee1284_ack_data_avail
drivers/parport/ieee1284.c, 577:
parport_ieee1284_ack_data_avail in parport_ieee1284_interrupt
./include/linux/parport.h, 474:
parport_ieee1284_interrupt in parport_generic_irq
drivers/usb/misc/uss720.c, 116:
parport_generic_irq in async_complete
[FUNC] get_1284_register(GFP_KERNEL)
drivers/usb/misc/uss720.c, 382:
get_1284_register in parport_uss720_read_status
drivers/parport/ieee1284.c, 555:
[FUNC_PTR]parport_uss720_read_status in parport_ieee1284_ack_data_avail
drivers/parport/ieee1284.c, 577:
parport_ieee1284_ack_data_avail in parport_ieee1284_interrupt
./include/linux/parport.h, 474:
parport_ieee1284_interrupt in parport_generic_irq
drivers/usb/misc/uss720.c, 116:
parport_generic_irq in async_complete
Note that [FUNC_PTR] means a function pointer call is used.
To fix these bugs, GFP_KERNEL is replaced with GFP_ATOMIC.
These bugs are found by my static analysis tool DSAC.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
b8abd3f42f