4.4-stable review patch. If anyone has any objections, please let me know.
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From: Jia-Ju Bai baijiaju1990@gmail.com
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 | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/usb/misc/uss720.c +++ b/drivers/usb/misc/uss720.c @@ -388,7 +388,7 @@ static unsigned char parport_uss720_frob mask &= 0x0f; val &= 0x0f; d = (priv->reg[1] & (~mask)) ^ val; - if (set_1284_register(pp, 2, d, GFP_KERNEL)) + if (set_1284_register(pp, 2, d, GFP_ATOMIC)) return 0; priv->reg[1] = d; return d & 0xf; @@ -398,7 +398,7 @@ static unsigned char parport_uss720_read { unsigned char ret;
- if (get_1284_register(pp, 1, &ret, GFP_KERNEL)) + if (get_1284_register(pp, 1, &ret, GFP_ATOMIC)) return 0; return ret & 0xf8; }