netdev - Re: [PATCH bpf-next 3/4] bpf: fix lockdep false positive in bpf_prog

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: <20190130194639.GB3085@hirez.programming.kicks-ass.net>
Date:   Wed, 30 Jan 2019 20:46:39 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc:     Alexei Starovoitov <ast@...nel.org>, davem@...emloft.net,
        daniel@...earbox.net, edumazet@...gle.com, jannh@...gle.com,
        netdev@...r.kernel.org, kernel-team@...com
Subject: Re: [PATCH bpf-next 3/4] bpf: fix lockdep false positive in
 bpf_prog_register

On Wed, Jan 30, 2019 at 11:32:43AM -0800, Alexei Starovoitov wrote:
> On Wed, Jan 30, 2019 at 11:10:58AM +0100, Peter Zijlstra wrote:
> > 
> > Why do you say this is not possible? All you need is 3 CPUs, one doing a
> > CPU online, one doing a perf ioctl() and one doing that
> > bpf_probe_register().
> 
> yeah. indeed. I'm impressed that lockdep figured it out
> while I missed it manually looking through the code and stack traces.

That's what it does :-)