linux-kernel - Re: [PATCH] perf/cgroup: correct indirection in perf_less_group

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: <20200321132515.GI20696@hirez.programming.kicks-ass.net>
Date:   Sat, 21 Mar 2020 14:25:15 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Ian Rogers <irogers@...gle.com>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Kan Liang <kan.liang@...ux.intel.com>,
        linux-kernel@...r.kernel.org, Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH] perf/cgroup: correct indirection in perf_less_group_idx

On Fri, Mar 20, 2020 at 06:38:39PM -0700, Ian Rogers wrote:
> The void* in perf_less_group_idx is to a cell in the array which points
> at a perf_event*, as such it is a perf_event**.
> 
> Fixes: 6eef8a7116de ("perf/core: Use min_heap in visit_groups_merge()")
> Author: John Sperbeck <jsperbeck@...gle.com>

That doesn't make sense, did he write the patch? Then there needs to be
a From: him and a SoB: him, If he reported the issue, it should be
Reported-by: him.

> Signed-off-by: Ian Rogers <irogers@...gle.com>
> ---
>  kernel/events/core.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index d22e4ba59dfa..a758c2311c53 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -3503,7 +3503,8 @@ static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
>  
>  static bool perf_less_group_idx(const void *l, const void *r)
>  {
> -	const struct perf_event *le = l, *re = r;
> +	const struct perf_event *le = *(const struct perf_event **)l;
> +	const struct perf_event *re = *(const struct perf_event **)r;

How did this not insta explode?