From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0AB761BC23; Fri, 4 Oct 2024 14:17:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728051456; cv=none; b=RlREb2f2eAS662A5vmjxpmiZa0e8CTS/6EAE6hTHXt1WCQl45r4GnyKZs6xt5T/quzdtQiIJ2EAbvtTdMfECX8/XODkraL4CWMmJPaGFx4P/PCv9RO44J9QncpckhTip/l4BQ4VZHrbR9fbXyVY7MeHiOWBj9+fXvyfmJ3fLxJY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728051456; c=relaxed/simple; bh=X4xq/NbuSXO7BJmTN7sQjUOwsklgqQwxSaneSZECvQ0=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=k4uVaZToPmNade46WoothUNqjEUTxl2NcW1IOIyRSuMhl7o1Ong/Sdx55Ih6U8YLyaBVZFwGX+PWJ+N3HEbvSkGMXsTpqYhunviW3ginix6guEtV8Boib37mk3C9k8LtCV1pbG1y5Nie0zIpvj1XFTpGDdDwH/UXwMuJ9XY6zyc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Tf+rHoSQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Tf+rHoSQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3CC7FC4CEC6; Fri, 4 Oct 2024 14:17:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728051455; bh=X4xq/NbuSXO7BJmTN7sQjUOwsklgqQwxSaneSZECvQ0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Tf+rHoSQ/tklcnMEZ3dJWLvQDwN4ADFiH2kLIMj1u8snJ4o8acLBlkjRuu+e1qna1 wkarJWHxyfmVtbjasS0QpsTjFgU3yxRot/a4gNbZuDAwt+MDMWqIW08Q3FVd+59yD0 t4lcXsXhaMCpQZI6QfKU/konm786J8y0qH/sB5S88zcaaGYqyLE9wXHQG/tmMksuMJ NYack17GuzKBSifVhXIQq0YsivHJJDm6yqZ9aYBSSYU2vguYc5B3i3CzCHWWxKU85X NSXF/OTniQ5vf0RnTj9uv6rcoMRykxVbqah6QFi8GWnMwaiwk2aC0JNxs1apS85zPU NCI626j645Asw== Date: Fri, 4 Oct 2024 23:17:32 +0900 From: Masami Hiramatsu (Google) To: Tatsuya S Cc: Steven Rostedt , Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH v3] ftrace: Hide a extra entry in stack trace Message-Id: <20241004231732.247301975e1e8f1511b50c6a@kernel.org> In-Reply-To: <20241002051347.4239-3-tatsuya.s2862@gmail.com> References: <20241002051347.4239-3-tatsuya.s2862@gmail.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 2 Oct 2024 14:13:48 +0900 Tatsuya S wrote: > A extra entry is shown on stack trace(CONFIG_UNWINDER_ORC=y). > > [003] ..... 110.171589: vfs_write <-__x64_sys_write > [003] ..... 110.171600: > => XXXXXXXXX (Wrong function name) > => vfs_write > => ksys_write > => do_syscall_64 > => entry_SYSCALL_64_after_hwframe > > To resolve this, increment skip for __ftrace_trace_stack() in > function_stack_trace_call(). > The reason why skip is incremented for __ftrace_trace_stack() > is because __ftrace_trace_stack() in stack trace is the only function > that wasn't skipped from anywhere. Hi Tatsuya, Can you focus on making test cases which checks what combinations caused this wrong values and what does not? Also it should be checked with various kconfigs. That is more valuable than making add-hoc fixes. Thank you, > > Signed-off-by: Tatsuya S > --- > V2 -> V3: Changed the place to increment skip number > V1 -> V2: Fixed redundant code > > kernel/trace/trace_functions.c | 24 +++++++++++------------- > 1 file changed, 11 insertions(+), 13 deletions(-) > > diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c > index 3b0cea37e029..27089d8e65d4 100644 > --- a/kernel/trace/trace_functions.c > +++ b/kernel/trace/trace_functions.c > @@ -203,23 +203,21 @@ function_trace_call(unsigned long ip, unsigned long parent_ip, > ftrace_test_recursion_unlock(bit); > } > > -#ifdef CONFIG_UNWINDER_ORC > -/* > - * Skip 2: > - * > - * function_stack_trace_call() > - * ftrace_call() > - */ > -#define STACK_SKIP 2 > -#else > /* > * Skip 3: > - * __trace_stack() > - * function_stack_trace_call() > - * ftrace_call() > + * Skipped functions if CONFIG_UNWINDER_ORC is defined > + * > + * __ftrace_trace_stack() > + * function_stack_trace_call() > + * ftrace_call() > + * > + * Otherwise > + * > + * __trace_stack() > + * function_stack_trace_call() > + * ftrace_call() > */ > #define STACK_SKIP 3 > -#endif > > static void > function_stack_trace_call(unsigned long ip, unsigned long parent_ip, > -- > 2.46.2 > -- Masami Hiramatsu (Google)