From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 B3A832475C8 for ; Thu, 3 Apr 2025 16:04:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743696301; cv=none; b=VlYfbigtygZOzSdtkP3F7a94igUgtAiXdXuN7Hay0dPTvHhFe3iEHR865VxT9HZvwEO6eTozbaPFMfHjpz7mcdPIP+J0Pd3K4PBzvc9mkuKY5CKhY5N86hwBXScbNz8gLB9d3IqwTYyMkOjvbwpkGjHEkVcUnPlFWwyz1toZkoc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743696301; c=relaxed/simple; bh=ayGeI1vgcM2JUZtOOCcTmsydqi0ZDi/vaxuzC7Jnfg0=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=oisw8OKporzaD7piY5D5iOecooJyru/Vwq6hWFOExH7JATN6Yc5le38j6pMpWkvQzyKjCH8ilUWIDmlbEvyq6oukaW3d9tubwV7WVkvQF3D3Rm9BpBU4mnuPGH2iZqjUa2WcQFgdHUBBdFrLtm+Ib5YhjNMRXddiHBycNNOkg/A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=TyzoZ9kF; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="TyzoZ9kF" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1743696298; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=7S1aRbEbJ/LqncEWKq79Hm3vAzySaW6ujzc1LbWde3U=; b=TyzoZ9kFzZUehwGcE87pRbX6UI2PHtwiGWQqTbGZJPpuhvc377seRm1OsvZfN460kI+f4a EY21TQfFEG/mt8/9QoykqwAvvCDUrNfxZ91D7xh3gQ1UmyGQMZq2AvHdqOWLaiX2f+eF87 W3RBgRsffCLp9fMybIoWFzRBkNUTzaA= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-106-SgeXaPdcPwap-geM_CtyrQ-1; Thu, 03 Apr 2025 12:04:54 -0400 X-MC-Unique: SgeXaPdcPwap-geM_CtyrQ-1 X-Mimecast-MFC-AGG-ID: SgeXaPdcPwap-geM_CtyrQ_1743696289 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A93FA195608A; Thu, 3 Apr 2025 16:04:48 +0000 (UTC) Received: from ashelat-thinkpadp1gen5.boston.csb (unknown [10.22.64.76]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5829E1955BC2; Thu, 3 Apr 2025 16:04:44 +0000 (UTC) From: Anubhav Shelat To: mpetlan@redhat.com, acme@kernel.org, namhyung@kernel.org, irogers@google.com, linux-perf-users@vger.kernel.org Cc: peterz@infradead.org, mingo@redhat.com, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, adrian.hunter@intel.com, kan.liang@linux.intel.com, dapeng1.mi@linux.intel.com, james.clark@linaro.org, Anubhav Shelat Subject: [PATCH] perf trace: always print return value for syscalls with set errpid Date: Thu, 3 Apr 2025 12:04:12 -0400 Message-ID: <20250403160411.159238-2-ashelat@redhat.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Currently some syscalls that have errpid set to true do not print a return value in perf trace. The syscalls that were consistently observed were set_robust_list and rseq. This is because perf cannot find their child process. This change ensures that the return value is always printed. Before: 0.256 ( 0.001 ms): set_robust_list(head: 0x7f09c77dba20, len: 24) = 0.259 ( 0.001 ms): rseq(rseq: 0x7f09c77dc0e0, rseq_len: 32, sig: 1392848979) = After: 0.270 ( 0.002 ms): set_robust_list(head: 0x7f0bb14a6a20, len: 24) = 0 0.273 ( 0.002 ms): rseq(rseq: 0x7f0bb14a70e0, rseq_len: 32, sig: 1392848979) = 0 Signed-off-by: Anubhav Shelat --- tools/perf/builtin-trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index 6ac51925ea42..c192f0219b2b 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -3005,8 +3005,8 @@ errno_print: { else if (sc->fmt->errpid) { struct thread *child = machine__find_thread(trace->host, ret, ret); + fprintf(trace->output, "%ld", ret); if (child != NULL) { - fprintf(trace->output, "%ld", ret); if (thread__comm_set(child)) fprintf(trace->output, " (%s)", thread__comm_str(child)); thread__put(child); -- 2.48.1