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From: Florian Weimer <fweimer@redhat.com>
To: Zack Weinberg via Libc-alpha <libc-alpha@sourceware.org>
Cc: Zack Weinberg <zack@owlfolio.org>
Subject: Re: RFC PATCH: Don't use /proc/self/maps to calculate size of initial thread stack
Date: Tue, 20 Sep 2022 14:16:04 +0200	[thread overview]
Message-ID: <87y1uemebf.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <9d232b1b-f123-4189-bf09-dd29aab6486a@www.fastmail.com> (Zack Weinberg via Libc-alpha's message of "Thu, 15 Sep 2022 12:09:36 -0400")

* Zack Weinberg via Libc-alpha:

>> process_vm_readv seems quite likely to get blocked by seccomp filters.
>
> I was worried about that too :-/

I think we see that in the pre-commit CI builder.

>> Maybe we can get the kernel to pass the end of the stack in the
>> auxiliary vector?
>
> Sure, but then what do we do on older kernels?  I'm reluctant to say
> "keep the old code" because we know this is breaking for people right
> now (although honestly "mount /proc earlier" isn't a terrible
> suggestion for a workaround).

We can keep doing what we are doing on older kernels.  I don't think we
should add yet another fallback path for this in case /proc isn't
available and the kernel doesn't provide the (future) AT_* entry.  *Two*
fallback paths instead of one seems a bit over the top.

Thanks,
Florian


  reply	other threads:[~2022-09-20 12:16 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-09 21:03 Zack Weinberg
2022-09-13  9:52 ` Florian Weimer
2022-09-13 22:03   ` Michael Hudson-Doyle
2022-09-15 16:09   ` Zack Weinberg
2022-09-20 12:16     ` Florian Weimer [this message]
2022-09-21 12:41       ` Zack Weinberg
2022-09-21 13:01         ` Florian Weimer
2022-09-21 20:58     ` Adhemerval Zanella Netto
2022-09-23 14:59       ` Zack Weinberg
2022-09-23 15:24         ` Adhemerval Zanella Netto
2022-09-23 18:57         ` Florian Weimer

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