From patchwork Fri Apr 9 10:58:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gerd Hoffmann X-Patchwork-Id: 1464281 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=eXRarbT8; dkim-atps=neutral Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4FGw9d0ZgFz9sTD for ; Fri, 9 Apr 2021 20:59:00 +1000 (AEST) Received: from localhost ([::1]:54590 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lUoqo-0002oa-T7 for incoming@patchwork.ozlabs.org; Fri, 09 Apr 2021 06:58:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55336) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lUoqM-0002nv-E2 for qemu-devel@nongnu.org; Fri, 09 Apr 2021 06:58:32 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:33942) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lUoqG-0002B2-3E for qemu-devel@nongnu.org; Fri, 09 Apr 2021 06:58:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1617965901; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=rslm5yc8I1k4SNmho/Dv/Y0uCjwL7HICN2RClJ7Sjbc=; b=eXRarbT8cvJIAFChOllpzZVf3v0xCUBrIEd6E9hMtQTYUp+axTSVtNVqnh8wP9dVrWvC4a xIG11nBG0eOvvSxMuUaAS4X7AMzbOj8JOEwA87nSg/VzzBEpvH2boqBKxm/Xsde3gBtwFV FWC0JqEXfheOUuu16LbbLMPALppkwzU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-552-XEQhgQAhPZaRXq9CIGzxDQ-1; Fri, 09 Apr 2021 06:58:20 -0400 X-MC-Unique: XEQhgQAhPZaRXq9CIGzxDQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3FF56100A616 for ; Fri, 9 Apr 2021 10:58:19 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-114-165.ams2.redhat.com [10.36.114.165]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D85045D9E3; Fri, 9 Apr 2021 10:58:12 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 9574618000AB; Fri, 9 Apr 2021 12:58:10 +0200 (CEST) From: Gerd Hoffmann To: qemu-devel@nongnu.org Subject: [PATCH v2] qemu-trace-stap: changing SYSTEMTAP_TAPSET considered harmful. Date: Fri, 9 Apr 2021 12:58:10 +0200 Message-Id: <20210409105810.374976-1-kraxel@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kraxel@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=63.128.21.124; envelope-from=kraxel@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Gerd Hoffmann , Stefan Hajnoczi Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Setting SYSTEMTAP_TAPSET to some value other than /usr/share/systemtap/tapsets results in systemtap not finding the standard tapset library any more, which in turn breaks tracing because pid() and other standard systemtap functions are not available any more. So using SYSTEMTAP_TAPSET to point systemtap to the qemu probes will only work for the prefix=/usr installs because both qemu and system tapsets in the same directory then. All other prefixes are broken. Fix that by using the "-I $tapsetdir" command line switch instead. Signed-off-by: Gerd Hoffmann --- scripts/qemu-trace-stap | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/scripts/qemu-trace-stap b/scripts/qemu-trace-stap index 90527eb974f4..eb6e951ff235 100755 --- a/scripts/qemu-trace-stap +++ b/scripts/qemu-trace-stap @@ -55,11 +55,6 @@ def tapset_dir(binary): return os.path.realpath(tapset) -def tapset_env(tapset_dir): - tenv = copy.copy(os.environ) - tenv["SYSTEMTAP_TAPSET"] = tapset_dir - return tenv - def cmd_run(args): prefix = probe_prefix(args.binary) tapsets = tapset_dir(args.binary) @@ -81,11 +76,11 @@ def cmd_run(args): # We request an 8MB buffer, since the stap default 1MB buffer # can be easily overflowed by frequently firing QEMU traces - stapargs = ["stap", "-s", "8"] + stapargs = ["stap", "-s", "8", "-I", tapsets ] if args.pid is not None: stapargs.extend(["-x", args.pid]) stapargs.extend(["-e", script]) - subprocess.call(stapargs, env=tapset_env(tapsets)) + subprocess.call(stapargs) def cmd_list(args): @@ -101,10 +96,9 @@ def cmd_list(args): if verbose: print("Listing probes with name '%s'" % script) - proc = subprocess.Popen(["stap", "-l", script], + proc = subprocess.Popen(["stap", "-I", tapsets, "-l", script], stdout=subprocess.PIPE, - universal_newlines=True, - env=tapset_env(tapsets)) + universal_newlines=True) out, err = proc.communicate() if proc.returncode != 0: print("No probes found, are the tapsets installed in %s" % tapset_dir(args.binary))