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 8171117FD; Tue, 1 Oct 2024 13:46:54 +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=1727790414; cv=none; b=LEG8//aC259PWq4wI63vOAavroVLf1wAhR8ehHg2ew4hcmAK1HFJAFfJdNr7AWLsA/5pcoE9+yPotzNOzFWPXTbbg88cPeY/PYENSYg22kaDF4oEqBE1DVbHxu09HZxmzbgn/VjEr79RUJ5pzPvB4fn1DZnbMY2FBPXUw0pcqpU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727790414; c=relaxed/simple; bh=VOwizr58+KJxA4KMlG2E00oPghiL9j7wzXU5Y4ngGD4=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=F6K9FnQyaln3M/XutBNEq0tN2anQewR13hYy57myjSoMEZTbAeoX1Dl5Mh/jt1/YDaijYA16IEbUV5zyJWPdRn6JBDJApgO9gODofoRhkiWIAOE/O20zXrg7/Z1duuYMwtjdwG21YRMkyW4UNWZOcT9gihdgl87eJ9WuReMXvT4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 71B87C4CEC6; Tue, 1 Oct 2024 13:46:53 +0000 (UTC) Date: Tue, 1 Oct 2024 09:47:42 -0400 From: Steven Rostedt To: ts Cc: "Masami Hiramatsu (Google)" , Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH v2] ftrace: Hide a extra entry in stack trace Message-ID: <20241001094742.1282d2ad@gandalf.local.home> In-Reply-To: <509829ab-98b5-4429-ba59-e1fc7b300682@gmail.com> References: <20240926061311.25625-1-tatsuya.s2862@gmail.com> <20240930085139.5d34f28236a67ef1e9143655@kernel.org> <509829ab-98b5-4429-ba59-e1fc7b300682@gmail.com> X-Mailer: Claws Mail 3.20.0git84 (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 Tue, 1 Oct 2024 22:27:03 +0900 ts wrote: > > ... > > sh-140 [001] ...1. 18.352601: myevent: (vfs_write+0x4/0x560) > > sh-140 [001] ...1. 18.352602: > > => ksys_write > > => do_syscall_64 > > => entry_SYSCALL_64_after_hwframe > > sh-140 [001] ...1. 18.352602: vfs_write <-ksys_write > > sh-140 [001] ...1. 18.352604: > > => ftrace_regs_call > > => vfs_write > > => ksys_write > > => do_syscall_64 > > => entry_SYSCALL_64_after_hwframe > > ------ > > As you can see, myevent skips "vfs_write". > > (and function tracer still have ftrace_regs_call() ) > > Thanks for the other tests. This issue may be function_trace_call() > specific problem. > > So I will change the place to increment skip number. My fear is that we are going to just break it elsewhere. The problem with the "skip" is that there's so many configurations when we get here, we may not really know what to skip. If the compiler inlines something, then we may skip something we do not want to. I rather have extra information than not enough. -- Steve