Re: [GIT PULL] Please pull proc and exec work for 5.7-rc1

[Bernd Edlinger]

On 4/2/20 11:46 PM, Linus Torvalds wrote:
> On Thu, Apr 2, 2020 at 2:00 PM Bernd Edlinger <bernd.edlinger@xxxxxxxxxx> wrote:
>>
>> There are two more patches, which might be of interest for you, just to
>> make the picture complete.
>> It is not clear if we go that way, or if Eric has a yet better idea.
>>
>> [PATCH v7 15/16] exec: Fix dead-lock in de_thread with ptrace_attach
>> https://www.spinics.net/lists/kernel/msg3459067.html
> 
> There is no way I would ever take that patch.
> 
> The amount of confusion in that patch is not acceptable. Randomly
> unlocking the new lock?
> 
> That code makes everything worse, it's completely incomprehensible,
> the locking rules make no sense ahwt-so-ever.
> 
> I'm seriously starting to feel like I should not have pulled this
> code, because the future looks _worse_ than what we used to have.
> 

No problem, sometimes they say the cure is worse than the disease,
and I would not rule out the possibility that this is also
an example for that.

My initial proposal was much smaller and probably more on the issue,
but in peer review it turned out that we want to solve the problem
from ground up.  Otherwise I saw no possibility how to get it approved.
That forced me in that direction that this took.

I just try to help with that.  But I do not insist in a specific
direction (-:

This is what I initially proposed:

[PATCH] exec: Fix a deadlock in ptrace
https://lore.kernel.org/lkml/AM6PR03MB5170B06F3A2B75EFB98D071AE4E60@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/


Thanks
Bernd.

> No. No no no. Eric, this is not an acceptable direction.
> 
>              Linus
>