From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: Jan Kara <jack@suse.cz>
Cc: akpm@linux-foundation.org, mgorman@techsingularity.net,
ak@linux.intel.com, mawilcox@microsoft.com,
viro@zeniv.linux.org.uk, ross.zwisler@linux.intel.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [BUG] mm: truncate: a possible sleep-in-atomic-context bug in truncate_exceptional_pvec_entries()
Date: Mon, 13 Aug 2018 17:30:55 +0800 [thread overview]
Message-ID: <91c44d76-ff62-7cdc-3f78-e0c3acc58637@gmail.com> (raw)
In-Reply-To: <20180813085635.GA8927@quack2.suse.cz>
On 2018/8/13 16:56, Jan Kara wrote:
> Hi,
>
> On Mon 13-08-18 11:10:23, Jia-Ju Bai wrote:
>> The kernel may sleep with holding a spinlock.
>>
>> The function call paths (from bottom to top) in Linux-4.16 are:
>>
>> [FUNC] schedule
>> fs/dax.c, 259: schedule in get_unlocked_mapping_entry
>> fs/dax.c, 450: get_unlocked_mapping_entry in __dax_invalidate_mapping_entry
>> fs/dax.c, 471: __dax_invalidate_mapping_entry in dax_delete_mapping_entry
>> mm/truncate.c, 97: dax_delete_mapping_entry in
>> truncate_exceptional_pvec_entries
>> mm/truncate.c, 82: spin_lock_irq in truncate_exceptional_pvec_entries
>>
>> I do not find a good way to fix, so I only report.
>> This is found by my static analysis tool (DSAC).
> Thanks for report but this is a false positive. Note that the lock is
> acquired only if we are not operating on DAX mapping but we can get to
> dax_delete_mapping_entry() only if we are operating on DAX mapping.
Thanks for your reply :)
My tool does not well check the path condition here...
Sorry for this false report.
Best wishes,
Jia-Ju Bai
prev parent reply other threads:[~2018-08-13 9:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-13 3:10 [BUG] mm: truncate: a possible sleep-in-atomic-context bug in truncate_exceptional_pvec_entries() Jia-Ju Bai
2018-08-13 8:56 ` Jan Kara
2018-08-13 9:30 ` Jia-Ju Bai [this message]
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