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From: Richard Weinberger <richard@nod.at>
To: Jia-Ju Bai <baijiaju1990@163.com>, dedekind1@gmail.com
Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ubifs: Fix a sleep-in-atomic bug in ubifs_read_nnode
Date: Mon, 5 Jun 2017 10:39:37 +0200	[thread overview]
Message-ID: <cb1e1f5d-5efc-e928-c962-02a5b772cc83@nod.at> (raw)
In-Reply-To: <0687ba2f-f7d5-4632-eebb-50bbadd8a4b0@nod.at>

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

  reply	other threads:[~2017-06-05  8:39 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-05  3:38 Jia-Ju Bai
2017-06-05  8:25 ` Richard Weinberger
2017-06-05  8:39   ` Richard Weinberger [this message]
2017-06-05  8:43   ` Jia-Ju Bai

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