From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9037C636CC for ; Mon, 13 Feb 2023 14:57:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229747AbjBMO5P (ORCPT ); Mon, 13 Feb 2023 09:57:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53670 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229787AbjBMO45 (ORCPT ); Mon, 13 Feb 2023 09:56:57 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93F8D1DB8D for ; Mon, 13 Feb 2023 06:56:30 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E8A7361122 for ; Mon, 13 Feb 2023 14:56:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09519C433EF; Mon, 13 Feb 2023 14:56:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1676300189; bh=Xc1fYH2mLElofxPbE9LcR0jg2YgXJ0Pmy/IyHi79s1k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p0Xrj745o3ho1xGHvamvSdPMukShylklkbUHMpOTVjqPmvhRyC9EMq0zgR+iV70tg MT6VJDES2BRqgi81kq42gzSc4gM90CMrDSE9A1+ord9a6U2rxrdEDTgGrwUF/TIVmd QUdAUdxQNd0AcC4KmODIx53Xzxg8vRTLbwerluxM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alexei Starovoitov , Kajetan Puchalski , Qais Yousef , John Stultz , Mathieu Desnoyers , Steven Rostedt , Yafang Shao Subject: [PATCH 6.1 098/114] tracing: Fix TASK_COMM_LEN in trace event format file Date: Mon, 13 Feb 2023 15:48:53 +0100 Message-Id: <20230213144747.255285019@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230213144742.219399167@linuxfoundation.org> References: <20230213144742.219399167@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Yafang Shao commit b6c7abd1c28a63ad633433d037ee15a1bc3023ba upstream. After commit 3087c61ed2c4 ("tools/testing/selftests/bpf: replace open-coded 16 with TASK_COMM_LEN"), the content of the format file under /sys/kernel/tracing/events/task/task_newtask was changed from field:char comm[16]; offset:12; size:16; signed:0; to field:char comm[TASK_COMM_LEN]; offset:12; size:16; signed:0; John reported that this change breaks older versions of perfetto. Then Mathieu pointed out that this behavioral change was caused by the use of __stringify(_len), which happens to work on macros, but not on enum labels. And he also gave the suggestion on how to fix it: :One possible solution to make this more robust would be to extend :struct trace_event_fields with one more field that indicates the length :of an array as an actual integer, without storing it in its stringified :form in the type, and do the formatting in f_show where it belongs. The result as follows after this change, $ cat /sys/kernel/tracing/events/task/task_newtask/format field:char comm[16]; offset:12; size:16; signed:0; Link: https://lore.kernel.org/lkml/Y+QaZtz55LIirsUO@google.com/ Link: https://lore.kernel.org/linux-trace-kernel/20230210155921.4610-1-laoar.shao@gmail.com/ Link: https://lore.kernel.org/linux-trace-kernel/20230212151303.12353-1-laoar.shao@gmail.com Cc: stable@vger.kernel.org Cc: Alexei Starovoitov Cc: Kajetan Puchalski CC: Qais Yousef Fixes: 3087c61ed2c4 ("tools/testing/selftests/bpf: replace open-coded 16 with TASK_COMM_LEN") Reported-by: John Stultz Debugged-by: Mathieu Desnoyers Suggested-by: Mathieu Desnoyers Suggested-by: Steven Rostedt Signed-off-by: Yafang Shao Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- include/linux/trace_events.h | 1 + include/trace/stages/stage4_event_fields.h | 3 +- kernel/trace/trace.h | 1 + kernel/trace/trace_events.c | 39 +++++++++++++++++----- kernel/trace/trace_export.c | 3 +- 5 files changed, 36 insertions(+), 11 deletions(-) diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 4342e996bcdb..0e373222a6df 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -270,6 +270,7 @@ struct trace_event_fields { const int align; const int is_signed; const int filter_type; + const int len; }; int (*define_fields)(struct trace_event_call *); }; diff --git a/include/trace/stages/stage4_event_fields.h b/include/trace/stages/stage4_event_fields.h index affd541fd25e..b6f679ae21aa 100644 --- a/include/trace/stages/stage4_event_fields.h +++ b/include/trace/stages/stage4_event_fields.h @@ -26,7 +26,8 @@ #define __array(_type, _item, _len) { \ .type = #_type"["__stringify(_len)"]", .name = #_item, \ .size = sizeof(_type[_len]), .align = ALIGN_STRUCTFIELD(_type), \ - .is_signed = is_signed_type(_type), .filter_type = FILTER_OTHER }, + .is_signed = is_signed_type(_type), .filter_type = FILTER_OTHER,\ + .len = _len }, #undef __dynamic_array #define __dynamic_array(_type, _item, _len) { \ diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 4eb6d6b97a9f..085a31b978a5 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1282,6 +1282,7 @@ struct ftrace_event_field { int offset; int size; int is_signed; + int len; }; struct prog_entry; diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 33e0b4f8ebe6..6a4696719297 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -114,7 +114,7 @@ trace_find_event_field(struct trace_event_call *call, char *name) static int __trace_define_field(struct list_head *head, const char *type, const char *name, int offset, int size, - int is_signed, int filter_type) + int is_signed, int filter_type, int len) { struct ftrace_event_field *field; @@ -133,6 +133,7 @@ static int __trace_define_field(struct list_head *head, const char *type, field->offset = offset; field->size = size; field->is_signed = is_signed; + field->len = len; list_add(&field->link, head); @@ -150,14 +151,28 @@ int trace_define_field(struct trace_event_call *call, const char *type, head = trace_get_fields(call); return __trace_define_field(head, type, name, offset, size, - is_signed, filter_type); + is_signed, filter_type, 0); } EXPORT_SYMBOL_GPL(trace_define_field); +int trace_define_field_ext(struct trace_event_call *call, const char *type, + const char *name, int offset, int size, int is_signed, + int filter_type, int len) +{ + struct list_head *head; + + if (WARN_ON(!call->class)) + return 0; + + head = trace_get_fields(call); + return __trace_define_field(head, type, name, offset, size, + is_signed, filter_type, len); +} + #define __generic_field(type, item, filter_type) \ ret = __trace_define_field(&ftrace_generic_fields, #type, \ #item, 0, 0, is_signed_type(type), \ - filter_type); \ + filter_type, 0); \ if (ret) \ return ret; @@ -166,7 +181,7 @@ EXPORT_SYMBOL_GPL(trace_define_field); "common_" #item, \ offsetof(typeof(ent), item), \ sizeof(ent.item), \ - is_signed_type(type), FILTER_OTHER); \ + is_signed_type(type), FILTER_OTHER, 0); \ if (ret) \ return ret; @@ -1588,12 +1603,17 @@ static int f_show(struct seq_file *m, void *v) seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n", field->type, field->name, field->offset, field->size, !!field->is_signed); - else - seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n", + else if (field->len) + seq_printf(m, "\tfield:%.*s %s[%d];\toffset:%u;\tsize:%u;\tsigned:%d;\n", (int)(array_descriptor - field->type), field->type, field->name, - array_descriptor, field->offset, + field->len, field->offset, field->size, !!field->is_signed); + else + seq_printf(m, "\tfield:%.*s %s[];\toffset:%u;\tsize:%u;\tsigned:%d;\n", + (int)(array_descriptor - field->type), + field->type, field->name, + field->offset, field->size, !!field->is_signed); return 0; } @@ -2379,9 +2399,10 @@ event_define_fields(struct trace_event_call *call) } offset = ALIGN(offset, field->align); - ret = trace_define_field(call, field->type, field->name, + ret = trace_define_field_ext(call, field->type, field->name, offset, field->size, - field->is_signed, field->filter_type); + field->is_signed, field->filter_type, + field->len); if (WARN_ON_ONCE(ret)) { pr_err("error code is %d\n", ret); break; diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c index d960f6b11b5e..58f3946081e2 100644 --- a/kernel/trace/trace_export.c +++ b/kernel/trace/trace_export.c @@ -111,7 +111,8 @@ static void __always_unused ____ftrace_check_##name(void) \ #define __array(_type, _item, _len) { \ .type = #_type"["__stringify(_len)"]", .name = #_item, \ .size = sizeof(_type[_len]), .align = __alignof__(_type), \ - is_signed_type(_type), .filter_type = FILTER_OTHER }, + is_signed_type(_type), .filter_type = FILTER_OTHER, \ + .len = _len }, #undef __array_desc #define __array_desc(_type, _container, _item, _len) __array(_type, _item, _len) -- 2.39.1