From: Florian Weimer <fw@deneb.enyo.de>
To: Paul Eggert <eggert@cs.ucla.edu>
Cc: Xiaoming Ni <nixiaoming@huawei.com>,
libc-alpha@sourceware.org, drepper.fsp@gmail.com, roland@gnu.org,
carlos@redhat.com, adhemerval.zanella@linaro.org,
wangle6@huawei.com, yukeji@huawei.com
Subject: Re: [PATCH v2] stdlib: realpath use malloc replace __alloca to reduce stack overflow risks [BZ #26341]
Date: Sun, 09 Aug 2020 14:38:06 +0200 [thread overview]
Message-ID: <87h7tc0zbl.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <22af5291-1e5b-d1ee-d333-7bed39402996@cs.ucla.edu> (Paul Eggert's message of "Sun, 9 Aug 2020 01:44:12 -0700")
* Paul Eggert:
> On 8/8/20 1:54 AM, Xiaoming Ni wrote:
>> To avoid possible stack overflow risks (the remaining stack space is uncertain
>> when realpath is called), should we sacrifice some efficiency and reduce the
>> stack space usage? Use malloc instead of alloca (4k+4k).
>
> 8 KiB of stack in a non-recursive I/O routine is not that big a deal. I don't
> see why we would need to worry about that.
I have seen a report that the temporary buffer in vfprintf on an
unbuffered stream causes crashes because after a hardware upgrade, the
available stack space was insufficient. That on-stack buffer is 8 KiB
as well.
next prev parent reply other threads:[~2020-08-09 12:38 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-07 10:16 Xiaoming Ni
2020-08-07 19:43 ` Adhemerval Zanella
2020-08-08 0:00 ` Paul Eggert
2020-08-08 9:14 ` Xiaoming Ni
2020-08-07 23:56 ` Paul Eggert
2020-08-08 8:54 ` Xiaoming Ni
2020-08-09 8:44 ` Paul Eggert
2020-08-09 12:38 ` Florian Weimer [this message]
2020-08-09 17:22 ` Paul Eggert
2020-08-10 13:40 ` Adhemerval Zanella
2020-08-11 9:54 ` Paul Eggert
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