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 A0F3CC433FE for ; Mon, 14 Nov 2022 06:44:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235705AbiKNGoS (ORCPT ); Mon, 14 Nov 2022 01:44:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229689AbiKNGoQ (ORCPT ); Mon, 14 Nov 2022 01:44:16 -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 A3AB5B1F for ; Sun, 13 Nov 2022 22:44:15 -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 1C5BA60E8B for ; Mon, 14 Nov 2022 06:44:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D491FC433D6; Mon, 14 Nov 2022 06:44:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1668408254; bh=Ncq+GzrJfogNzTs9Gq9rY7ph1j8hjVIOLVuCgg/VvQk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=tZ4WkTHbZEe+eGJZU0U8TJcdn7XLxuZvEg+byBL+XpFwVkHWs0mZp2NpNrtXJ6eZ6 OIpvJ+zRvTJT0B9KSDnMk+LEzFVzkll6bE+fDxHRPMJP67GoVTQutlwHVZZMwoxNNK OBLtbP/idzDMqv7hDv2fwj/oq6vHP+njD9D7ISinfW5D1TmJsSpE9KXgJNgimjSD/f NbkfW7/37oSZDksZ2nHNhE1LBjF5qsyQakcBOTqgcPBq+P1C0ikxuFk1ko/GZ6/5KY +irpya7/+G4fTjGjqk6Gkru8FT2fJYEmeoPJONzcdYPmuF8Pi1vbIssvUriYFZqXKa D94l9BFIwXeBA== Date: Mon, 14 Nov 2022 15:44:12 +0900 From: Masami Hiramatsu (Google) To: Rafael Mendonca Cc: Steven Rostedt , linux-kernel@vger.kernel.org Subject: Re: [PATCH] tracing/eprobe: Fix warning in filter creation Message-Id: <20221114154412.0e4ba0a1b93c1f5ebff26446@kernel.org> In-Reply-To: <20221108202148.1020111-1-rafaelmendsr@gmail.com> References: <20221108202148.1020111-1-rafaelmendsr@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 8 Nov 2022 17:21:47 -0300 Rafael Mendonca wrote: > The filter pointer (filterp) passed to create_filter() function must be a > pointer that references a NULL pointer, otherwise, we get a warning when > adding a filter option to the event probe: > > root@localhost:/sys/kernel/tracing# echo 'e:egroup/stat_runtime_4core sched/sched_stat_runtime \ > runtime=$runtime:u32 if cpu < 4' >> dynamic_events > [ 5034.340439] ------------[ cut here ]------------ > [ 5034.341258] WARNING: CPU: 0 PID: 223 at kernel/trace/trace_events_filter.c:1939 create_filter+0x1db/0x250 > [...] stripped > [ 5034.345518] RIP: 0010:create_filter+0x1db/0x250 > [...] stripped > [ 5034.351604] Call Trace: > [ 5034.351803] > [ 5034.351959] ? process_preds+0x1b40/0x1b40 > [ 5034.352241] ? rcu_read_lock_bh_held+0xd0/0xd0 > [ 5034.352604] ? kasan_set_track+0x29/0x40 > [ 5034.352904] ? kasan_save_alloc_info+0x1f/0x30 > [ 5034.353264] create_event_filter+0x38/0x50 > [ 5034.353573] __trace_eprobe_create+0x16f4/0x1d20 > [ 5034.353964] ? eprobe_dyn_event_release+0x360/0x360 > [ 5034.354363] ? mark_held_locks+0xa6/0xf0 > [ 5034.354684] ? _raw_spin_unlock_irqrestore+0x35/0x60 > [ 5034.355105] ? trace_hardirqs_on+0x41/0x120 > [ 5034.355417] ? _raw_spin_unlock_irqrestore+0x35/0x60 > [ 5034.355751] ? __create_object+0x5b7/0xcf0 > [ 5034.356027] ? lock_is_held_type+0xaf/0x120 > [ 5034.356362] ? rcu_read_lock_bh_held+0xb0/0xd0 > [ 5034.356716] ? rcu_read_lock_bh_held+0xd0/0xd0 > [ 5034.357084] ? kasan_set_track+0x29/0x40 > [ 5034.357411] ? kasan_save_alloc_info+0x1f/0x30 > [ 5034.357715] ? __kasan_kmalloc+0xb8/0xc0 > [ 5034.357985] ? write_comp_data+0x2f/0x90 > [ 5034.358302] ? __sanitizer_cov_trace_pc+0x25/0x60 > [ 5034.358691] ? argv_split+0x381/0x460 > [ 5034.358949] ? write_comp_data+0x2f/0x90 > [ 5034.359240] ? eprobe_dyn_event_release+0x360/0x360 > [ 5034.359620] trace_probe_create+0xf6/0x110 > [ 5034.359940] ? trace_probe_match_command_args+0x240/0x240 > [ 5034.360376] eprobe_dyn_event_create+0x21/0x30 > [ 5034.360709] create_dyn_event+0xf3/0x1a0 > [ 5034.360983] trace_parse_run_command+0x1a9/0x2e0 > [ 5034.361297] ? dyn_event_release+0x500/0x500 > [ 5034.361591] dyn_event_write+0x39/0x50 > [ 5034.361851] vfs_write+0x311/0xe50 > [ 5034.362091] ? dyn_event_seq_next+0x40/0x40 > [ 5034.362376] ? kernel_write+0x5b0/0x5b0 > [ 5034.362637] ? write_comp_data+0x2f/0x90 > [ 5034.362937] ? __sanitizer_cov_trace_pc+0x25/0x60 > [ 5034.363258] ? ftrace_syscall_enter+0x544/0x840 > [ 5034.363563] ? write_comp_data+0x2f/0x90 > [ 5034.363837] ? __sanitizer_cov_trace_pc+0x25/0x60 > [ 5034.364156] ? write_comp_data+0x2f/0x90 > [ 5034.364468] ? write_comp_data+0x2f/0x90 > [ 5034.364770] ksys_write+0x158/0x2a0 > [ 5034.365022] ? __ia32_sys_read+0xc0/0xc0 > [ 5034.365344] __x64_sys_write+0x7c/0xc0 > [ 5034.365669] ? syscall_enter_from_user_mode+0x53/0x70 > [ 5034.366084] do_syscall_64+0x60/0x90 > [ 5034.366356] entry_SYSCALL_64_after_hwframe+0x63/0xcd > [ 5034.366767] RIP: 0033:0x7ff0b43938f3 > [...] stripped > [ 5034.371892] > [ 5034.374720] ---[ end trace 0000000000000000 ]--- > > Fixes: 752be5c5c910 ("tracing/eprobe: Add eprobe filter support") > Signed-off-by: Rafael Mendonca Acked-by: Masami Hiramatsu (Google) Thanks! > --- > kernel/trace/trace_eprobe.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c > index 5dd0617e5df6..c2153bf59936 100644 > --- a/kernel/trace/trace_eprobe.c > +++ b/kernel/trace/trace_eprobe.c > @@ -900,7 +900,7 @@ static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[ > > static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const char *argv[]) > { > - struct event_filter *dummy; > + struct event_filter *dummy = NULL; > int i, ret, len = 0; > char *p; > > -- > 2.34.1 > -- Masami Hiramatsu (Google)