From patchwork Fri Jul 3 14:44:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alan Maguire X-Patchwork-Id: 1322408 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=oracle.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=oracle.com header.i=@oracle.com header.a=rsa-sha256 header.s=corp-2020-01-29 header.b=jTE6oOsC; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49yyVY43P8z9sQt for ; Sat, 4 Jul 2020 00:47:33 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726063AbgGCOrd (ORCPT ); Fri, 3 Jul 2020 10:47:33 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:37090 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726039AbgGCOrc (ORCPT ); Fri, 3 Jul 2020 10:47:32 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 063EcUTZ047306; Fri, 3 Jul 2020 14:46:44 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2020-01-29; bh=lq5sVyx1UalpiHI43tkae6jUDgNoIVMM3yi7/H6bvs8=; b=jTE6oOsCjzcSV44EGWqEhTyApm7H87Rd9aB2gKS/9D61v5YhqQV9iA8wd2+ZfzSRYcqX e2TA4ORyc1AGbbYgWSO8Fngr6gXM1VrCzEZ42nYF6EZ+mYKNrdMcY2SgAcOjJcgZQkXI eXn4FANQtqTmoYVRXjbCJRHtpM4eUVUdCi1aSGgE0gE7lDVNvoIndoT4y9WuFYyqmxr6 evqfXTu4GvtEo0Jyp6F7vVkOQVN3zMhi/7PnCBbqQ9xTnPRlaLLIh2fkl4fv1PjRbRoR nhgohcqyuOnbfm7v7CuMkuNhTTDtfXpIcks7aiYWWkVbMWThCSWZKwlgIwfGccZDU3ee 7g== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2120.oracle.com with ESMTP id 31wxrnp2wc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 03 Jul 2020 14:46:44 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 063EgrXb193561; Fri, 3 Jul 2020 14:44:44 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserp3020.oracle.com with ESMTP id 31xg1cjyw0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 03 Jul 2020 14:44:43 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 063EigIT023486; Fri, 3 Jul 2020 14:44:42 GMT Received: from localhost.uk.oracle.com (/10.175.204.239) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 03 Jul 2020 14:44:42 +0000 From: Alan Maguire To: rostedt@goodmis.org, mingo@redhat.com, ast@kernel.org, daniel@iogearbox.net Cc: kafai@fb.com, songliubraving@fb.com, yhs@fb.com, andriin@fb.com, john.fastabend@gmail.com, kpsingh@chromium.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, Alan Maguire Subject: [PATCH bpf-next 1/2] bpf: use dedicated bpf_trace_printk event instead of trace_printk() Date: Fri, 3 Jul 2020 15:44:27 +0100 Message-Id: <1593787468-29931-2-git-send-email-alan.maguire@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1593787468-29931-1-git-send-email-alan.maguire@oracle.com> References: <1593787468-29931-1-git-send-email-alan.maguire@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9670 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 malwarescore=0 mlxlogscore=999 suspectscore=0 bulkscore=0 mlxscore=0 adultscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2007030102 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9670 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 mlxlogscore=999 priorityscore=1501 impostorscore=0 bulkscore=0 clxscore=1015 malwarescore=0 phishscore=0 adultscore=0 cotscore=-2147483648 lowpriorityscore=0 suspectscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2007030102 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org The bpf helper bpf_trace_printk() uses trace_printk() under the hood. This leads to an alarming warning message originating from trace buffer allocation which occurs the first time a program using bpf_trace_printk() is loaded. We can instead create a trace event for bpf_trace_printk() and enable it in-kernel when/if we encounter a program using the bpf_trace_printk() helper. With this approach, trace_printk() is not used directly and no warning message appears. This work was started by Steven (see Link) and finished by Alan; added Steven's Signed-off-by with his permission. Link: https://lore.kernel.org/r/20200628194334.6238b933@oasis.local.home Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Alan Maguire --- kernel/trace/Makefile | 2 ++ kernel/trace/bpf_trace.c | 41 +++++++++++++++++++++++++++++++++++++---- kernel/trace/bpf_trace.h | 34 ++++++++++++++++++++++++++++++++++ 3 files changed, 73 insertions(+), 4 deletions(-) create mode 100644 kernel/trace/bpf_trace.h diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 6575bb0..aeba5ee 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -31,6 +31,8 @@ ifdef CONFIG_GCOV_PROFILE_FTRACE GCOV_PROFILE := y endif +CFLAGS_bpf_trace.o := -I$(src) + CFLAGS_trace_benchmark.o := -I$(src) CFLAGS_trace_events_filter.o := -I$(src) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 1d874d8..cdbafc4 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2,6 +2,10 @@ /* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com * Copyright (c) 2016 Facebook */ +#define CREATE_TRACE_POINTS + +#include "bpf_trace.h" + #include #include #include @@ -11,6 +15,7 @@ #include #include #include +#include #include #include @@ -374,6 +379,28 @@ static void bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype, } } +static DEFINE_SPINLOCK(trace_printk_lock); + +#define BPF_TRACE_PRINTK_SIZE 1024 + +static inline int bpf_do_trace_printk(const char *fmt, ...) +{ + static char buf[BPF_TRACE_PRINTK_SIZE]; + unsigned long flags; + va_list ap; + int ret; + + spin_lock_irqsave(&trace_printk_lock, flags); + va_start(ap, fmt); + ret = vsnprintf(buf, BPF_TRACE_PRINTK_SIZE, fmt, ap); + va_end(ap); + if (ret > 0) + trace_bpf_trace_printk(buf); + spin_unlock_irqrestore(&trace_printk_lock, flags); + + return ret; +} + /* * Only limited trace_printk() conversion specifiers allowed: * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pB %pks %pus %s @@ -483,8 +510,7 @@ static void bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype, */ #define __BPF_TP_EMIT() __BPF_ARG3_TP() #define __BPF_TP(...) \ - __trace_printk(0 /* Fake ip */, \ - fmt, ##__VA_ARGS__) + bpf_do_trace_printk(fmt, ##__VA_ARGS__) #define __BPF_ARG1_TP(...) \ ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64)) \ @@ -518,13 +544,20 @@ static void bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype, .arg2_type = ARG_CONST_SIZE, }; +int bpf_trace_printk_enabled; + const struct bpf_func_proto *bpf_get_trace_printk_proto(void) { /* * this program might be calling bpf_trace_printk, - * so allocate per-cpu printk buffers + * so enable the associated bpf_trace/bpf_trace_printk event. */ - trace_printk_init_buffers(); + if (!bpf_trace_printk_enabled) { + if (trace_set_clr_event("bpf_trace", "bpf_trace_printk", 1)) + pr_warn_ratelimited("could not enable bpf_trace_printk events"); + else + bpf_trace_printk_enabled = 1; + } return &bpf_trace_printk_proto; } diff --git a/kernel/trace/bpf_trace.h b/kernel/trace/bpf_trace.h new file mode 100644 index 0000000..9acbc11 --- /dev/null +++ b/kernel/trace/bpf_trace.h @@ -0,0 +1,34 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM bpf_trace + +#if !defined(_TRACE_BPF_TRACE_H) || defined(TRACE_HEADER_MULTI_READ) + +#define _TRACE_BPF_TRACE_H + +#include + +TRACE_EVENT(bpf_trace_printk, + + TP_PROTO(const char *bpf_string), + + TP_ARGS(bpf_string), + + TP_STRUCT__entry( + __string(bpf_string, bpf_string) + ), + + TP_fast_assign( + __assign_str(bpf_string, bpf_string); + ), + + TP_printk("%s", __get_str(bpf_string)) +); + +#endif /* _TRACE_BPF_TRACE_H */ + +#undef TRACE_INCLUDE_PATH +#define TRACE_INCLUDE_PATH . +#define TRACE_INCLUDE_FILE bpf_trace + +#include From patchwork Fri Jul 3 14:44:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alan Maguire X-Patchwork-Id: 1322405 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=oracle.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=oracle.com header.i=@oracle.com header.a=rsa-sha256 header.s=corp-2020-01-29 header.b=camBN+Ni; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49yySJ0ZTbz9sSy for ; Sat, 4 Jul 2020 00:45:36 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726039AbgGCOpb (ORCPT ); Fri, 3 Jul 2020 10:45:31 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:35024 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726416AbgGCOp3 (ORCPT ); Fri, 3 Jul 2020 10:45:29 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 063Egmca010573; Fri, 3 Jul 2020 14:44:47 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2020-01-29; bh=TkYOCaQ92FrXOw0/1NjMuLX7ItnHP73SNldBIYcl4S0=; b=camBN+NiVanMOp9DQ+Xxtw3ctxYhQ28H2aTZ3Ie9bnFW8iBHieXkhh1SYkXKHz9oyLdc Jw9Y5GCXjV2N0ghTL35EXX6kUEPN2foSuttJplP6dZMI8Y30Ns98BS3g7X19C86v7ubZ 4t/qxyX/z/mD1zIubu+8663XeCjRQCt7I24IhJFS8GzGHtitnYvsZ6pI38h0GCwBsTx1 JZ6ULBfvETLc+Zl2tbZhNLbz9Hb2+p2HG4b3xlp49HP6UHbCnPM6lQBjARGRaacSXZER cPPmvIaecDfJZznb0HfseQPNtXnWwTUM89ogIWjdFfaRjBqTOchfXxCpnzbIZv0eTXmR lg== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by aserp2120.oracle.com with ESMTP id 31xx1eawy0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 03 Jul 2020 14:44:47 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 063EhwYj034788; Fri, 3 Jul 2020 14:44:46 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3030.oracle.com with ESMTP id 31xg22sjua-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 03 Jul 2020 14:44:46 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 063Eij6S013246; Fri, 3 Jul 2020 14:44:45 GMT Received: from localhost.uk.oracle.com (/10.175.204.239) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 03 Jul 2020 14:44:45 +0000 From: Alan Maguire To: rostedt@goodmis.org, mingo@redhat.com, ast@kernel.org, daniel@iogearbox.net Cc: kafai@fb.com, songliubraving@fb.com, yhs@fb.com, andriin@fb.com, john.fastabend@gmail.com, kpsingh@chromium.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, Alan Maguire Subject: [PATCH bpf-next 2/2] selftests/bpf: add selftests verifying bpf_trace_printk() behaviour Date: Fri, 3 Jul 2020 15:44:28 +0100 Message-Id: <1593787468-29931-3-git-send-email-alan.maguire@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1593787468-29931-1-git-send-email-alan.maguire@oracle.com> References: <1593787468-29931-1-git-send-email-alan.maguire@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9670 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 spamscore=0 phishscore=0 malwarescore=0 mlxlogscore=999 adultscore=0 mlxscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2007030102 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9670 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 clxscore=1015 adultscore=0 suspectscore=0 mlxlogscore=999 cotscore=-2147483648 lowpriorityscore=0 malwarescore=0 phishscore=0 impostorscore=0 mlxscore=0 spamscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2007030102 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Simple selftest that verifies bpf_trace_printk() returns a sensible value and tracing messages appear. Signed-off-by: Alan Maguire --- .../selftests/bpf/prog_tests/trace_printk.c | 71 ++++++++++++++++++++++ tools/testing/selftests/bpf/progs/trace_printk.c | 21 +++++++ 2 files changed, 92 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/trace_printk.c create mode 100644 tools/testing/selftests/bpf/progs/trace_printk.c diff --git a/tools/testing/selftests/bpf/prog_tests/trace_printk.c b/tools/testing/selftests/bpf/prog_tests/trace_printk.c new file mode 100644 index 0000000..a850cba --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/trace_printk.c @@ -0,0 +1,71 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020, Oracle and/or its affiliates. */ + +#include + +#include "trace_printk.skel.h" + +#define TRACEBUF "/sys/kernel/debug/tracing/trace_pipe" +#define SEARCHMSG "testing,testing" + +void test_trace_printk(void) +{ + int err, duration = 0, found = 0; + struct trace_printk *skel; + struct trace_printk__bss *bss; + char buf[1024]; + int fd = -1; + + skel = trace_printk__open(); + if (CHECK(!skel, "skel_open", "failed to open skeleton\n")) + return; + + err = trace_printk__load(skel); + if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err)) + goto cleanup; + + bss = skel->bss; + + err = trace_printk__attach(skel); + if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err)) + goto cleanup; + + fd = open(TRACEBUF, O_RDONLY); + if (CHECK(fd < 0, "could not open trace buffer", + "error %d opening %s", errno, TRACEBUF)) + goto cleanup; + + /* We do not want to wait forever if this test fails... */ + fcntl(fd, F_SETFL, O_NONBLOCK); + + /* wait for tracepoint to trigger */ + sleep(1); + trace_printk__detach(skel); + + if (CHECK(bss->trace_printk_ran == 0, + "bpf_trace_printk never ran", + "ran == %d", bss->trace_printk_ran)) + goto cleanup; + + if (CHECK(bss->trace_printk_ret <= 0, + "bpf_trace_printk returned <= 0 value", + "got %d", bss->trace_printk_ret)) + goto cleanup; + + /* verify our search string is in the trace buffer */ + while (read(fd, buf, sizeof(buf)) >= 0) { + if (strstr(buf, SEARCHMSG) != NULL) + found++; + } + + if (CHECK(!found, "message from bpf_trace_printk not found", + "no instance of %s in %s", SEARCHMSG, TRACEBUF)) + goto cleanup; + + printf("ran %d times; last return value %d, with %d instances of msg\n", + bss->trace_printk_ran, bss->trace_printk_ret, found); +cleanup: + trace_printk__destroy(skel); + if (fd != -1) + close(fd); +} diff --git a/tools/testing/selftests/bpf/progs/trace_printk.c b/tools/testing/selftests/bpf/progs/trace_printk.c new file mode 100644 index 0000000..8ff6d49 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/trace_printk.c @@ -0,0 +1,21 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2020, Oracle and/or its affiliates. + +#include "vmlinux.h" +#include +#include + +char _license[] SEC("license") = "GPL"; + +int trace_printk_ret = 0; +int trace_printk_ran = 0; + +SEC("tracepoint/sched/sched_switch") +int sched_switch(void *ctx) +{ + static const char fmt[] = "testing,testing %d\n"; + + trace_printk_ret = bpf_trace_printk(fmt, sizeof(fmt), + ++trace_printk_ran); + return 0; +}