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 X-Spam-Level: X-Spam-Status: No, score=-13.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B59AC3F2D1 for ; Mon, 2 Mar 2020 12:45:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CD6CD217F4 for ; Mon, 2 Mar 2020 12:45:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=embeddedor.com header.i=@embeddedor.com header.b="GPgT2SFP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727702AbgCBMpg (ORCPT ); Mon, 2 Mar 2020 07:45:36 -0500 Received: from gateway32.websitewelcome.com ([192.185.145.125]:30857 "EHLO gateway32.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726654AbgCBMpg (ORCPT ); Mon, 2 Mar 2020 07:45:36 -0500 Received: from cm12.websitewelcome.com (cm12.websitewelcome.com [100.42.49.8]) by gateway32.websitewelcome.com (Postfix) with ESMTP id E8A70B87ED for ; Mon, 2 Mar 2020 06:45:33 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 8kRxjTfnwvBMd8kRxjOZhB; Mon, 02 Mar 2020 06:45:33 -0600 X-Authority-Reason: nr=8 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=embeddedor.com; s=default; h=Content-Type:MIME-Version:Message-ID:Subject: Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=tl8+3TSgEq6tAPLGgAaiTefQihYsH/3BU/lyPlzh9Iw=; b=GPgT2SFPXC633+7BHksASa2QrB eSZdc9l+tQjgEhZq4fWnnmHBHFoidyCPI5v7Cv8Pfuj8IYFOAfGkn8ZwprgS+2OBG0NRxgjFOxWNt /GumsrW7HyY1ul5wqVhBikb1J7lbO8bBQJvb0XSqE6vNbcMW0tYRKUCP9bC1BLjzmiNuKdTuzkeMS 0yvUMDbKGBNNoRTeQxD93jxJqR04IQi8DI2kstGeB0Ia7KzdnQRylZF5FViTV7OJlljM1W+LUPeYy /icrTlhZ5rrnojU7P8iNvpLG5cJPTkBnFgibpwTSew8R7p8k8beGEtSIK+xR8a8fnFNycWzWlcpxn 7xsGDKhQ==; Received: from [201.162.161.142] (port=43686 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j8kRv-0001vX-HB; Mon, 02 Mar 2020 06:45:32 -0600 Date: Mon, 2 Mar 2020 06:48:32 -0600 From: "Gustavo A. R. Silva" To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim Cc: linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH][next] perf: Replace zero-length array with flexible-array member Message-ID: <20200302124832.GA7504@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 201.162.161.142 X-Source-L: No X-Exim-ID: 1j8kRv-0001vX-HB X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [201.162.161.142]:43686 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 55 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva --- include/linux/perf_event.h | 4 ++-- include/uapi/linux/perf_event.h | 2 +- tools/perf/bench/sched-messaging.c | 2 +- tools/perf/builtin-inject.c | 2 +- tools/perf/builtin-script.c | 2 +- tools/perf/builtin-timechart.c | 2 +- tools/perf/util/annotate.h | 4 ++-- tools/perf/util/branch.h | 2 +- tools/perf/util/cputopo.h | 2 +- tools/perf/util/dso.h | 4 ++-- tools/perf/util/event.h | 2 +- tools/perf/util/jitdump.c | 2 +- tools/perf/util/jitdump.h | 6 +++--- tools/perf/util/ordered-events.h | 2 +- tools/perf/util/pstack.c | 2 +- tools/perf/util/symbol.h | 2 +- tools/perf/util/unwind-libunwind-local.c | 2 +- 17 files changed, 22 insertions(+), 22 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 68e21e828893..11b63013e1d9 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -61,7 +61,7 @@ struct perf_guest_info_callbacks { struct perf_callchain_entry { __u64 nr; - __u64 ip[0]; /* /proc/sys/kernel/perf_event_max_stack */ + __u64 ip[]; /* /proc/sys/kernel/perf_event_max_stack */ }; struct perf_callchain_entry_ctx { @@ -113,7 +113,7 @@ struct perf_raw_record { struct perf_branch_stack { __u64 nr; __u64 hw_idx; - struct perf_branch_entry entries[0]; + struct perf_branch_entry entries[]; }; struct task_struct; diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 397cfd65b3fe..d71023c46058 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -453,7 +453,7 @@ struct perf_event_query_bpf { /* * User provided buffer to store program ids */ - __u32 ids[0]; + __u32 ids[]; }; /* diff --git a/tools/perf/bench/sched-messaging.c b/tools/perf/bench/sched-messaging.c index 97e4a4fb3362..71d830d7b923 100644 --- a/tools/perf/bench/sched-messaging.c +++ b/tools/perf/bench/sched-messaging.c @@ -40,7 +40,7 @@ struct sender_context { unsigned int num_fds; int ready_out; int wakefd; - int out_fds[0]; + int out_fds[]; }; struct receiver_context { diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c index 7e124a7b8bfd..8f983877c42d 100644 --- a/tools/perf/builtin-inject.c +++ b/tools/perf/builtin-inject.c @@ -51,7 +51,7 @@ struct perf_inject { struct event_entry { struct list_head node; u32 tid; - union perf_event event[0]; + union perf_event event[]; }; static int output_bytes(struct perf_inject *inject, void *buf, size_t sz) diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c index e2406b291c1c..4576b0b226fb 100644 --- a/tools/perf/builtin-script.c +++ b/tools/perf/builtin-script.c @@ -2568,7 +2568,7 @@ static int __cmd_script(struct perf_script *script) struct script_spec { struct list_head node; struct scripting_ops *ops; - char spec[0]; + char spec[]; }; static LIST_HEAD(script_specs); diff --git a/tools/perf/builtin-timechart.c b/tools/perf/builtin-timechart.c index 9e84fae9b096..0ba568efa939 100644 --- a/tools/perf/builtin-timechart.c +++ b/tools/perf/builtin-timechart.c @@ -128,7 +128,7 @@ struct sample_wrapper { struct sample_wrapper *next; u64 timestamp; - unsigned char data[0]; + unsigned char data[]; }; #define TYPE_NONE 0 diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h index 001258601a37..d641029d0c4a 100644 --- a/tools/perf/util/annotate.h +++ b/tools/perf/util/annotate.h @@ -143,7 +143,7 @@ struct annotation_line { u32 idx; int idx_asm; int data_nr; - struct annotation_data data[0]; + struct annotation_data data[]; }; struct disasm_line { @@ -226,7 +226,7 @@ void symbol__calc_percent(struct symbol *sym, struct evsel *evsel); struct sym_hist { u64 nr_samples; u64 period; - struct sym_hist_entry addr[0]; + struct sym_hist_entry addr[]; }; struct cyc_hist { diff --git a/tools/perf/util/branch.h b/tools/perf/util/branch.h index 88e00d268f6f..e353a5c1aa72 100644 --- a/tools/perf/util/branch.h +++ b/tools/perf/util/branch.h @@ -39,7 +39,7 @@ struct branch_entry { struct branch_stack { u64 nr; - struct branch_entry entries[0]; + struct branch_entry entries[]; }; struct branch_type_stat { diff --git a/tools/perf/util/cputopo.h b/tools/perf/util/cputopo.h index 7bf6b811f715..6201c3790d86 100644 --- a/tools/perf/util/cputopo.h +++ b/tools/perf/util/cputopo.h @@ -22,7 +22,7 @@ struct numa_topology_node { struct numa_topology { u32 nr; - struct numa_topology_node nodes[0]; + struct numa_topology_node nodes[]; }; struct cpu_topology *cpu_topology__new(void); diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h index 2db64b79617a..d7ba29ad19ff 100644 --- a/tools/perf/util/dso.h +++ b/tools/perf/util/dso.h @@ -136,7 +136,7 @@ struct dso_cache { struct rb_node rb_node; u64 offset; u64 size; - char data[0]; + char data[]; }; struct auxtrace_cache; @@ -208,7 +208,7 @@ struct dso { struct nsinfo *nsinfo; struct dso_id id; refcount_t refcnt; - char name[0]; + char name[]; }; /* dso__for_each_symbol - iterate over the symbols of given type diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h index 85223159737c..adda817569d8 100644 --- a/tools/perf/util/event.h +++ b/tools/perf/util/event.h @@ -79,7 +79,7 @@ struct sample_read { struct ip_callchain { u64 nr; - u64 ips[0]; + u64 ips[]; }; struct branch_stack; diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c index e3ccb0ce1938..32bb05e03fb2 100644 --- a/tools/perf/util/jitdump.c +++ b/tools/perf/util/jitdump.c @@ -57,7 +57,7 @@ struct debug_line_info { unsigned long vma; unsigned int lineno; /* The filename format is unspecified, absolute path, relative etc. */ - char const filename[0]; + char const filename[]; }; struct jit_tool { diff --git a/tools/perf/util/jitdump.h b/tools/perf/util/jitdump.h index f2c3823cc81a..ab2842def83d 100644 --- a/tools/perf/util/jitdump.h +++ b/tools/perf/util/jitdump.h @@ -93,7 +93,7 @@ struct debug_entry { uint64_t addr; int lineno; /* source line number starting at 1 */ int discrim; /* column discriminator, 0 is default */ - const char name[0]; /* null terminated filename, \xff\0 if same as previous entry */ + const char name[]; /* null terminated filename, \xff\0 if same as previous entry */ }; struct jr_code_debug_info { @@ -101,7 +101,7 @@ struct jr_code_debug_info { uint64_t code_addr; uint64_t nr_entry; - struct debug_entry entries[0]; + struct debug_entry entries[]; }; struct jr_code_unwinding_info { @@ -110,7 +110,7 @@ struct jr_code_unwinding_info { uint64_t unwinding_size; uint64_t eh_frame_hdr_size; uint64_t mapped_size; - const char unwinding_data[0]; + const char unwinding_data[]; }; union jr_entry { diff --git a/tools/perf/util/ordered-events.h b/tools/perf/util/ordered-events.h index 0920fb0ec6cc..75345946c4b9 100644 --- a/tools/perf/util/ordered-events.h +++ b/tools/perf/util/ordered-events.h @@ -29,7 +29,7 @@ typedef int (*ordered_events__deliver_t)(struct ordered_events *oe, struct ordered_events_buffer { struct list_head list; - struct ordered_event event[0]; + struct ordered_event event[]; }; struct ordered_events { diff --git a/tools/perf/util/pstack.c b/tools/perf/util/pstack.c index 80ff41fc45be..a1d1e4ef6257 100644 --- a/tools/perf/util/pstack.c +++ b/tools/perf/util/pstack.c @@ -15,7 +15,7 @@ struct pstack { unsigned short top; unsigned short max_nr_entries; - void *entries[0]; + void *entries[]; }; struct pstack *pstack__new(unsigned short max_nr_entries) diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h index 93fc43db1be3..ff4f4c47e148 100644 --- a/tools/perf/util/symbol.h +++ b/tools/perf/util/symbol.h @@ -55,7 +55,7 @@ struct symbol { u8 inlined:1; u8 arch_sym; bool annotate2; - char name[0]; + char name[]; }; void symbol__delete(struct symbol *sym); diff --git a/tools/perf/util/unwind-libunwind-local.c b/tools/perf/util/unwind-libunwind-local.c index b4649f5a0c2f..9aededc0bc06 100644 --- a/tools/perf/util/unwind-libunwind-local.c +++ b/tools/perf/util/unwind-libunwind-local.c @@ -243,7 +243,7 @@ struct eh_frame_hdr { * encoded_t fde_addr; * } binary_search_table[fde_count]; */ - char data[0]; + char data[]; } __packed; static int unwind_spec_ehframe(struct dso *dso, struct machine *machine, -- 2.25.0