linux-kernel - Re: perf: perf_fuzzer crashes on Pentium 4 systems

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]

Date:   Wed, 3 Apr 2019 22:19:44 +0300
From:   Cyrill Gorcunov <gorcunov@...il.com>
To:     Vince Weaver <vincent.weaver@...ne.edu>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        linux-kernel@...r.kernel.org,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Namhyung Kim <namhyung@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jiri Olsa <jolsa@...hat.com>,
        Stephane Eranian <eranian@...gle.com>
Subject: Re: perf: perf_fuzzer crashes on Pentium 4 systems

On Wed, Apr 03, 2019 at 10:59:32AM -0400, Vince Weaver wrote:
> 
> so moving this to its own thread.
> 
> There was a two-part question asked.
> 	1. Can the perf-fuzzer crash a Pentium 4 system
> 	2. Does anyone care anymore?
> 
> The answer to #1 turns out to be "yes"
> I'm not sure about #2 (but it's telling my p4 test system hadn't been 
> turned on in over 3 years).
> 
> In any case the perf_fuzzer can crash my p4 system within an hour or so.  
> The debugging from this isn't great, I forget what the preferred debug 
> things to enable in the kernel hacking menu are.
> 
> Here is one crash that just happened:
> 
> The instruction at RIP is unhelpfully
> 	./arch/x86/include/asm/processor.h:400
> which is
> 	DECLARE_PER_CPU_FIRST(union irq_stack_union, irq_stack_union) __visible;
> 
> Though looking at the assembly it looks like
> 	p4_pmu_enable_event() is called with NULL as the paramater.
> 

You know, seems I got what happened -- p4_general_events do
not cover all general events, they stop at PERF_COUNT_HW_BUS_CYCLES,
while more 3 general event left. This is 'cause I've not been following
pmu evolution in code. I will try to cover this events hopefully more
less soon and send you a patch to test (if you don't mind).