From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2D49915FA96; Fri, 21 Jun 2024 20:11:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719000709; cv=none; b=rtY+c265HuIaKmlJ4XZUIj2y99Wc1ypo/pcy8V1wDw2SKj2eyQDrgw5JS2aycjB+ARGwaVCJOdY8Mr5A46zMdEJZV631JKHLd67IZY2ma+gm0fyn6C0qoQkVvQoEHZCQoIxpLM02Y+A6LejuVDOwQh8LudEmpIWkaixCssL6i1I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719000709; c=relaxed/simple; bh=pCEU19nWiLGEThyMAl4Y7guiba2ywnvjD28mzCNRvSg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Y7P77kHhboilrdGP+shzh7MeXE2h5CO/lTE5YaailBJqJUjXJHqny176VaOzGiYLwAmVmDDfUo0Bvx3Wqcc6PJuyqfOJyfXIFuEUiUkX4S26VbQECHfQ0wTYM2JD4TAs31QSKWKVfdkQmy/XXrbLwBVlYW4OlU8pvooZExibvWk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=fls5evho; arc=none smtp.client-ip=192.198.163.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="fls5evho" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1719000707; x=1750536707; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=pCEU19nWiLGEThyMAl4Y7guiba2ywnvjD28mzCNRvSg=; b=fls5evho7uje0HGWlO2Rnjxs5wchujeshKsxsIxz6deqGkq0MmrThhZr cegSYDCZtzydJrQFUJkNnNndjq1Y2oJazo6AI9cqtE8eyTopz6ZlYNRfe pr5ASIybk/5CbzF/JGvqLh4VuUzP8xDfRfnaQRKRuYWZYhNjMvB4m6G2i AF3MjcU2l1yHJ5tT60PS4mcizGFiTYigAEjacSCFVXb6LsCCWLZAblKLh nvTar+vi9CCzxwBs8MYVstvo7MK46FbVDSX2jmMfcHs/x/mtWZ0p9Mbmn +RGMEGiM0zgMaJ2Jesx/kzybiFHsWBS4fT87fcvfv8qhlG50RDBHR4HlJ A==; X-CSE-ConnectionGUID: 4P31pL9VROeObGZLkkx8TQ== X-CSE-MsgGUID: ECfUMjsaR1ylq3Xk6peTNQ== X-IronPort-AV: E=McAfee;i="6700,10204,11110"; a="15744827" X-IronPort-AV: E=Sophos;i="6.08,255,1712646000"; d="scan'208";a="15744827" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Jun 2024 13:11:46 -0700 X-CSE-ConnectionGUID: p1uIZORLSQOLXie1AJhiew== X-CSE-MsgGUID: 8lNXs7SWRbCxlCy8ikS3Ug== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,255,1712646000"; d="scan'208";a="73434161" Received: from linux.intel.com ([10.54.29.200]) by orviesa002.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Jun 2024 13:11:47 -0700 Received: from [10.212.73.237] (kliang2-mobl1.ccr.corp.intel.com [10.212.73.237]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by linux.intel.com (Postfix) with ESMTPS id 89A5520B5703; Fri, 21 Jun 2024 13:11:44 -0700 (PDT) Message-ID: Date: Fri, 21 Jun 2024 16:11:43 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 4/4] perf mem: Fix a segfault with NULL event->name To: Namhyung Kim , Arnaldo Carvalho de Melo , Ian Rogers Cc: Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, Guilherme Amadio References: <20240621170528.608772-1-namhyung@kernel.org> <20240621170528.608772-5-namhyung@kernel.org> Content-Language: en-US From: "Liang, Kan" In-Reply-To: <20240621170528.608772-5-namhyung@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2024-06-21 1:05 p.m., Namhyung Kim wrote: > Guilherme reported a crash in perf mem record. It's because the > perf_mem_event->name was NULL on his machine. It should just return > a NULL string when it has no format string in the name. > > But I'm not sure why it returns TRUE if it doesn't have event_name in > perf_pmu__mem_events_supported(). AMD doesn't have the event_name. struct perf_mem_event perf_mem_events_amd[PERF_MEM_EVENTS__MAX] = { E(NULL, NULL, NULL, false, 0), E(NULL, NULL, NULL, false, 0), E("mem-ldst", "%s//", NULL, false, 0), }; It looks like as long as it's a "ibs_op" PMU, the mem event is always available. The "ibs_op" check has been moved into perf_pmu__arch_init(). So the event_name is empty. The "e->tag" in the perf_pmu__mem_events_init() can help to skip the case E(NULL, NULL, NULL, false, 0). So the perf_pmu__mem_events_supported() returns TRUE for the !event_name. Thanks, Kan > > The backtrace at the crash is below: > > Program received signal SIGSEGV, Segmentation fault. > __strchrnul_avx2 () at ../sysdeps/x86_64/multiarch/strchr-avx2.S:67 > 67 vmovdqu (%rdi), %ymm2 > (gdb) bt > #0 __strchrnul_avx2 () at ../sysdeps/x86_64/multiarch/strchr-avx2.S:67 > #1 0x00007ffff6c982de in __find_specmb (format=0x0) at printf-parse.h:82 > #2 __printf_buffer (buf=buf@entry=0x7fffffffc760, format=format@entry=0x0, ap=ap@entry=0x7fffffffc880, > mode_flags=mode_flags@entry=0) at vfprintf-internal.c:649 > #3 0x00007ffff6cb7840 in __vsnprintf_internal (string=, maxlen=, format=0x0, > args=0x7fffffffc880, mode_flags=mode_flags@entry=0) at vsnprintf.c:96 > #4 0x00007ffff6cb787f in ___vsnprintf (string=, maxlen=, format=, > args=) at vsnprintf.c:103 > #5 0x00005555557b9391 in scnprintf (buf=0x555555fe9320 "", size=100, fmt=0x0) > at ../lib/vsprintf.c:21 > #6 0x00005555557b74c3 in perf_pmu__mem_events_name (i=0, pmu=0x555556832180) at util/mem-events.c:106 > #7 0x00005555557b7ab9 in perf_mem_events__record_args (rec_argv=0x55555684c000, argv_nr=0x7fffffffca20) > at util/mem-events.c:252 > #8 0x00005555555e370d in __cmd_record (argc=3, argv=0x7fffffffd760, mem=0x7fffffffcd80) at builtin-mem.c:156 > #9 0x00005555555e49c4 in cmd_mem (argc=4, argv=0x7fffffffd760) at builtin-mem.c:514 > #10 0x000055555569716c in run_builtin (p=0x555555fcde80 , argc=8, argv=0x7fffffffd760) at perf.c:349 > #11 0x0000555555697402 in handle_internal_command (argc=8, argv=0x7fffffffd760) at perf.c:402 > #12 0x0000555555697560 in run_argv (argcp=0x7fffffffd59c, argv=0x7fffffffd590) at perf.c:446 > #13 0x00005555556978a6 in main (argc=8, argv=0x7fffffffd760) at perf.c:562 > > Reported-by: Guilherme Amadio > Closes: https://lore.kernel.org/linux-perf-users/Zlns_o_IE5L28168@cern.ch > Signed-off-by: Namhyung Kim > --- > tools/perf/util/mem-events.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/perf/util/mem-events.c b/tools/perf/util/mem-events.c > index 6dda47bb774f..429079329e48 100644 > --- a/tools/perf/util/mem-events.c > +++ b/tools/perf/util/mem-events.c > @@ -86,7 +86,7 @@ static const char *perf_pmu__mem_events_name(int i, struct perf_pmu *pmu) > return NULL; > > e = &pmu->mem_events[i]; > - if (!e) > + if (!e || !e->name) > return NULL; > > if (i == PERF_MEM_EVENTS__LOAD || i == PERF_MEM_EVENTS__LOAD_STORE) {