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SubjectRe: [PATCH] coredump: Limit what can interrupt coredumps
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On 8/21/21 10:47 AM, Olivier Langlois wrote:
> On Sat, 2021-08-21 at 06:08 -0400, Olivier Langlois wrote:
>> On Tue, 2021-08-17 at 20:57 -0600, Jens Axboe wrote:
>>>
>>> Olivier, I sent a 5.10 version for Nathan, any chance you can test
>>> this
>>> one for the current kernels? Basically this one should work for
>>> 5.11+,
>>> and the later 5.10 version is just for 5.10. I'm going to send it
>>> out
>>> separately for review.
>>>
>>> I do think this is the right solution, barring a tweak maybe on
>>> testing
>>> notify == TWA_SIGNAL first before digging into the task struct. But
>>> the
>>> principle is sound, and it'll work for other users of TWA_SIGNAL as
>>> well. None right now as far as I can tell, but the live patching is
>>> switching to TIF_NOTIFY_SIGNAL as well which will also cause issues
>>> with
>>> coredumps potentially.
>>>
>> Ok, I am going to give it a shot. This solution is probably superior
>> to
>> the previous attempt as it does not inject io_uring dependency into
>> the
>> coredump module.
>>
>> The small extra change that I alluded to in my previous reply will
>> still be relevant even if we go with your patch...
>>
>> I'll come back soon with your patch testing result and my small extra
>> change that I keep teasing about.
>>
>> Greetings,
>>
> Jens,
>
> your patch doesn't compile with 5.12+. AFAIK, the reason is that
> JOBCTL_TASK_WORK is gone.
>
> Wouldn't just a call to tracehook_notify_signal from do_coredump be
> enough and backward compatible with every possible stable branches?

That version is just for 5.10, the first I posted is applicable to
5.11+

--
Jens Axboe

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