releases/4.9.129/usb-misc-uss720-fix-two-sleep-in-atomic-context-bugs.patch

   1 From bc8acc214d3f1cafebcbcd101a695bbac716595d Mon Sep 17 00:00:00 2001
   2 From: Jia-Ju Bai <baijiaju1990@gmail.com>
   3 Date: Sat, 1 Sep 2018 16:25:08 +0800
   4 Subject: usb: misc: uss720: Fix two sleep-in-atomic-context bugs
   5
   6 From: Jia-Ju Bai <baijiaju1990@gmail.com>
   7
   8 commit bc8acc214d3f1cafebcbcd101a695bbac716595d upstream.
   9
  10 async_complete() in uss720.c is a completion handler function for the
  11 USB driver. So it should not sleep, but it is can sleep according to the
  12 function call paths (from bottom to top) in Linux-4.16.
  13
  14 [FUNC] set_1284_register(GFP_KERNEL)
  15 drivers/usb/misc/uss720.c, 372:
  16   set_1284_register in parport_uss720_frob_control
  17 drivers/parport/ieee1284.c, 560:
  18   [FUNC_PTR]parport_uss720_frob_control in parport_ieee1284_ack_data_avail
  19 drivers/parport/ieee1284.c, 577:
  20   parport_ieee1284_ack_data_avail in parport_ieee1284_interrupt
  21 ./include/linux/parport.h, 474:
  22   parport_ieee1284_interrupt in parport_generic_irq
  23 drivers/usb/misc/uss720.c, 116:
  24   parport_generic_irq in async_complete
  25
  26 [FUNC] get_1284_register(GFP_KERNEL)
  27 drivers/usb/misc/uss720.c, 382:
  28   get_1284_register in parport_uss720_read_status
  29 drivers/parport/ieee1284.c, 555:
  30   [FUNC_PTR]parport_uss720_read_status in parport_ieee1284_ack_data_avail
  31 drivers/parport/ieee1284.c, 577:
  32   parport_ieee1284_ack_data_avail in parport_ieee1284_interrupt
  33 ./include/linux/parport.h, 474:
  34   parport_ieee1284_interrupt in parport_generic_irq
  35 drivers/usb/misc/uss720.c, 116:
  36   parport_generic_irq in async_complete
  37
  38 Note that [FUNC_PTR] means a function pointer call is used.
  39
  40 To fix these bugs, GFP_KERNEL is replaced with GFP_ATOMIC.
  41
  42 These bugs are found by my static analysis tool DSAC.
  43
  44 Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
  45 Cc: stable <stable@vger.kernel.org>
  46 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  47
  48 ---
  49  drivers/usb/misc/uss720.c |    4 ++--
  50  1 file changed, 2 insertions(+), 2 deletions(-)
  51
  52 --- a/drivers/usb/misc/uss720.c
  53 +++ b/drivers/usb/misc/uss720.c
  54 @@ -385,7 +385,7 @@ static unsigned char parport_uss720_frob
  55         mask &= 0x0f;
  56         val &= 0x0f;
  57         d = (priv->reg[1] & (~mask)) ^ val;
  58 -       if (set_1284_register(pp, 2, d, GFP_KERNEL))
  59 +       if (set_1284_register(pp, 2, d, GFP_ATOMIC))
  60                 return 0;
  61         priv->reg[1] = d;
  62         return d & 0xf;
  63 @@ -395,7 +395,7 @@ static unsigned char parport_uss720_read
  64  {
  65         unsigned char ret;
  66
  67 -       if (get_1284_register(pp, 1, &ret, GFP_KERNEL))
  68 +       if (get_1284_register(pp, 1, &ret, GFP_ATOMIC))
  69                 return 0;
  70         return ret & 0xf8;
  71  }