lkml.org 
[lkml]   [2018]   [Sep]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] hid: hid-core: Fix a sleep-in-atomic-context bug in __hid_request()
From
Date


On 2018/9/5 16:29, Jiri Kosina wrote:
> On Sat, 1 Sep 2018, Jia-Ju Bai wrote:
>
>> 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.
> Could you please rewrite the changelog so that it's human readable? The
> above is a bit hard to understand, I think something along the lines of
> "__hid_request() has to be allocating with GFP_ATOMIC because there are
> the following callchains leading to __hid_request() being an atomic
> context: ... a->b->c.._hid_request()" etc.
>

Okay, I will send a new patch.


Best wishes,
Jia-Ju Bai

\
 
 \ /
  Last update: 2018-09-06 04:35    [W:0.056 / U:0.600 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site