linux-kernel - Re: [PATCH 7/8] perf tools: Check fallback error and order

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: <bbffa9eb-0102-4c35-8b1a-4e26634aa878@amd.com>
Date: Tue, 15 Oct 2024 09:51:50 +0530
From: Ravi Bangoria <ravi.bangoria@....com>
To: Namhyung Kim <namhyung@...nel.org>, Ian Rogers <irogers@...gle.com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
 Kan Liang <kan.liang@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>,
 Adrian Hunter <adrian.hunter@...el.com>,
 Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...nel.org>,
 LKML <linux-kernel@...r.kernel.org>, linux-perf-users@...r.kernel.org,
 Mark Rutland <mark.rutland@....com>, James Clark <james.clark@....com>,
 Kajol Jain <kjain@...ux.ibm.com>, Thomas Richter <tmricht@...ux.ibm.com>,
 Atish Patra <atishp@...shpatra.org>, Palmer Dabbelt <palmer@...osinc.com>,
 Mingwei Zhang <mizhang@...gle.com>, Ravi Bangoria <ravi.bangoria@....com>
Subject: Re: [PATCH 7/8] perf tools: Check fallback error and order

> @@ -2366,9 +2403,6 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
>  	return 0;
>  
>  try_fallback:
> -	if (evsel__precise_ip_fallback(evsel))
> -		goto retry_open;
> -
>  	if (evsel__ignore_missing_thread(evsel, perf_cpu_map__nr(cpus),
>  					 idx, threads, thread, err)) {
>  		/* We just removed 1 thread, so lower the upper nthreads limit. */
> @@ -2385,11 +2419,15 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
>  	if (err == -EMFILE && rlimit__increase_nofile(&set_rlimit))
>  		goto retry_open;
>  
> -	if (err != -EINVAL || idx > 0 || thread > 0)
> -		goto out_close;
> +	if (err == -EOPNOTSUPP && evsel__precise_ip_fallback(evsel))
> +		goto retry_open;

This will change the behavior of events like instructions:P on AMD.

Without patch:
  $ ./perf record -e instructions:P -- true
  [ perf record: Woken up 2 times to write data ]
  [ perf record: Captured and wrote 0.009 MB perf.data (9 samples) ]

With the patch:

  $ ./perf record -e instructions:P -- true
  Error:
  The instructions:Pu event is not supported.

Thanks,
Ravi