linux-kernel - Re: [PATCH] ubifs: Fix a sleep-in-atomic bug in ubifs_read

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Message-ID: <0687ba2f-f7d5-4632-eebb-50bbadd8a4b0@nod.at>
Date:   Mon, 5 Jun 2017 10:25:40 +0200
From:   Richard Weinberger <richard@....at>
To:     Jia-Ju Bai <baijiaju1990@....com>, dedekind1@...il.com
Cc:     linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ubifs: Fix a sleep-in-atomic bug in ubifs_read_nnode

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?

Thanks,
//richard