[PATCH] ubifs: Fix a sleep-in-atomic bug in ubifs_read_nnode
Richard Weinberger
richard at nod.at
Mon Jun 5 01:39:37 PDT 2017
Am 05.06.2017 um 10:25 schrieb Richard Weinberger:
> Jia-Ju Bai,
>
> Am 05.06.2017 um 05:38 schrieb Jia-Ju Bai:
>> The driver may sleep under a spin lock, and the function call path is:
>> ubifs_change_lp (acquire the lock by spin_lock)
>> change_category
>> ubifs_remove_from_cat
>> remove_from_lpt_heap
>> dbg_check_heap
>> ubifs_lpt_lookup
>> ubifs_read_nnode
>> kzalloc(GFP_NOFS) --> may sleep
>>
>> To fix it, "GFP_NOFS" is replaced with "GFP_ATOMIC".
>
> So, this happens only when dbg_check_heap() is activated, right?
Why do we call change_category() anyway with c->space_lock held?
Thanks,
//richard
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