The driver may sleep with holding a spinlock. The function call paths (from bottom to top) in Linux-4.16 are: [FUNC] hid_alloc_report_buf(GFP_KERNEL) drivers/hid/hid-core.c, 1435: hid_alloc_report_buf in __hid_request ./include/linux/hid.h, 1023: __hid_request in hid_hw_request drivers/hid/hid-picolcd_core.c, 111: hid_hw_request in picolcd_send_and_wait drivers/hid/hid-picolcd_core.c, 100: _raw_spin_lock_irqsave in picolcd_send_and_wait [FUNC] hid_alloc_report_buf(GFP_KERNEL) drivers/hid/hid-core.c, 1435: hid_alloc_report_buf in __hid_request ./include/linux/hid.h, 1023: __hid_request in hid_hw_request drivers/hid/hid-picolcd_core.c, 245: hid_hw_request in picolcd_reset drivers/hid/hid-picolcd_core.c, 235: _raw_spin_lock_irqsave in picolcd_reset [FUNC] hid_alloc_report_buf(GFP_KERNEL) drivers/hid/hid-core.c, 1435: hid_alloc_report_buf in __hid_request ./include/linux/hid.h, 1023: __hid_request in hid_hw_request drivers/hid/hid-picolcd_fb.c, 215: hid_hw_request in picolcd_fb_reset drivers/hid/hid-picolcd_fb.c, 206: _raw_spin_lock_irqsave in picolcd_fb_reset [FUNC] hid_alloc_report_buf(GFP_KERNEL) drivers/hid/hid-core.c, 1435: hid_alloc_report_buf in __hid_request ./include/linux/hid.h, 1023: __hid_request in hid_hw_request drivers/hid/hid-lg4ff.c, 465: hid_hw_request in lg4ff_play drivers/hid/hid-lg4ff.c, 441: _raw_spin_lock_irqsave in lg4ff_play To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC. This bug is found by my static analysis tool DSAC. Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx> --- drivers/hid/hid-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 3942ee61bd1c..c886af00c8c9 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -1442,7 +1442,7 @@ void __hid_request(struct hid_device *hid, struct hid_report *report, int ret; u32 len; - buf = hid_alloc_report_buf(report, GFP_KERNEL); + buf = hid_alloc_report_buf(report, GFP_ATOMIC); if (!buf) return; -- 2.17.0
