linux-kernel - Re: [PATCH 2/2] trace/kprobe: Remove limit on kretprobe maxactive

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210615210351.602bc03e@rorschach.local.home>
Date:   Tue, 15 Jun 2021 21:03:51 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Masami Hiramatsu <mhiramat@...nel.org>
Cc:     "Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>,
        Anton Blanchard <anton@...abs.org>,
        linux-kernel@...r.kernel.org, Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH 2/2] trace/kprobe: Remove limit on kretprobe maxactive

On Wed, 16 Jun 2021 09:46:22 +0900
Masami Hiramatsu <mhiramat@...nel.org> wrote:

> To avoid such trouble, I had set the 4096 limitation for the maxactive
> parameter. Of course 4096 may not enough for some use-cases. I'm welcome
> to expand it (e.g. 32k, isn't it enough?), but removing the limitation
> may cause OOM trouble easily.

What if you just made the max as 10 * number of possible cpus, or 4096,
which ever is greater? Why would a user need more?

I'd still like to get a wrapper around function graph tracing so that
kretprobes could use it. I think that would get rid of the requirement
of maxactive, because isn't that just used to have a way to know the
original return value?

-- Steve