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SubjectRe: [f2fs-dev] [f2fs bug] infinite loop in f2fs_get_meta_page_nofail()
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On 2020/10/8 5:53, jaegeuk@kernel.org wrote:
> On 10/07, Eric Biggers wrote:
>> [moved linux-fsdevel to Bcc]
>>
>> On Wed, Oct 07, 2020 at 02:18:19AM -0700, syzbot wrote:
>>> Hello,
>>>
>>> syzbot found the following issue on:
>>>
>>> HEAD commit: a804ab08 Add linux-next specific files for 20201006
>>> git tree: linux-next
>>> console output: https://syzkaller.appspot.com/x/log.txt?x=17fe30bf900000
>>> kernel config: https://syzkaller.appspot.com/x/.config?x=26c1b4cc4a62ccb
>>> dashboard link: https://syzkaller.appspot.com/bug?extid=ee250ac8137be41d7b13
>>> compiler: gcc (GCC) 10.1.0-syz 20200507
>>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1336413b900000
>>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12f7392b900000
>>>
>>> The issue was bisected to:
>>>
>>> commit eede846af512572b1f30b34f9889d7df64c017d4
>>> Author: Jaegeuk Kim <jaegeuk@kernel.org>
>>> Date: Fri Oct 2 21:17:35 2020 +0000
>>>
>>> f2fs: f2fs_get_meta_page_nofail should not be failed
>>>
>>
>> Jaegeuk, it looks like the loop you added in the above commit doesn't terminate
>> if the requested page is beyond the end of the device.
>
> Yes, that will go infinite loop. Otherwise, it will trigger a panic during
> the device reboot. Let me think how to avoid that before trying to get the
> wrong lba access.

Delivering f2fs_get_sum_page()'s return value needs a lot of codes change, I think
we can just zeroing sum_page in error case, as we have already shutdown f2fs via
calling f2fs_stop_checkpoint(), then f2fs_cp_error() will stop all updates to
filesystem data including summary pages.

Thoughts?

Thanks,

>
>>
>> - Eric
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> .
>

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