usb: misc: uss720: Fix two sleep-in-atomic-context bugs
commit2ccd62789ef0ec1bd8efd52d9581b84331f6004d
authorJia-Ju Bai <baijiaju1990@gmail.com>
Sat, 1 Sep 2018 08:25:08 +0000 (1 16:25 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 26 Sep 2018 06:36:36 +0000 (26 08:36 +0200)
tree0dd591436d14ee0aa75968569db4ab6e572980fe
parentb1507f458d22fe86334ebc53b8f26de74598c37a
usb: misc: uss720: Fix two sleep-in-atomic-context bugs

commit bc8acc214d3f1cafebcbcd101a695bbac716595d 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>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/misc/uss720.c