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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 68263C35FF2 for ; Tue, 17 Sep 2024 08:27:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=rst1FmnXmWXyG5Zt+l5GAYthdwa5p4GYYWpoTO/Kp00=; b=15C+A6df6rqAgPDueAIE/MB4RB 0PAWA6JO8AKiyrmJdqcHEuaM58wJA1Xm3WgnIMEioaEYGt4Ks4AaSdHHCY6sSxosjXcL8vSyhnD0Y jVKa0J3RCTlh5ge5effcPIoiPR/BmpxOqLyWS8rHte8sFfUQsXfGQxStTj52qVWEbDH19U/7qU3MS kkAHywrQ0rqQo4jGUV8OhY+eu2EEQC2nVpugbcPkwVkOzh2A7EecgVaJTcNwCzH+23FlT8lnu990N WkS8/SkEuF9XUjVXXESaia36zlNRHXQLNOnbL3rUik1+qnfqDZ0meEqUVm2pZt+bQELcurJ4CrB4T 5DSKddnA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1sqTYh-00000005gy9-3avR; Tue, 17 Sep 2024 08:27:40 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1sqTXc-00000005gtM-25sc for linux-arm-kernel@lists.infradead.org; Tue, 17 Sep 2024 08:26:33 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id E7BD95C025B; Tue, 17 Sep 2024 08:26:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 138CCC4CEC6; Tue, 17 Sep 2024 08:26:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726561591; bh=yX8WybCaNIWhzTkbjSWRx9jTOwkDZkYTQGTxrYRDcI4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=rifoRMQL3+zR0FXXPfapgOmRYlb9GjXyEP6JxSCdSt51CcQHUrVMqO8TJqg3ogKsD cXQkEv/N8owpRl+A1Jv2OudODUg3VP1xEKvq/PUU3vPWmiTwXYlnG5GxTyK5lJkAf+ G/lupAVj5DCYBCDBtBZ9+zTNBNZuFbrn9hC0HElmW17HAoaYRtD/RaaAgPmPfKQPFm Y9Ycxexf9DHiMrhUvOvYEfJzgMfay78SwfZDaxOh71qbrAuQBFKBwTNHpfB/ZHDZ3Y 12Tyb6aq37kF/XIhLPT2P/14mNmmKDD1M13i4+UNfkU/p6TI/MEZ5li8iYSIpiodmk xrIyGp2Uf68zg== Date: Tue, 17 Sep 2024 09:26:25 +0100 From: Will Deacon To: Steven Rostedt Cc: Catalin Marinas , linux-arm-kernel@lists.infradead.org, "Masami Hiramatsu (Google)" , Florent Revest , linux-trace-kernel@vger.kernel.org, LKML , Alexei Starovoitov , Jiri Olsa , Arnaldo Carvalho de Melo , Daniel Borkmann , Alan Maguire , Mark Rutland Subject: Re: [PATCH v14 03/19] function_graph: Pass ftrace_regs to entryfunc Message-ID: <20240917082624.GC27290@willie-the-truck> References: <172615368656.133222.2336770908714920670.stgit@devnote2> <172615372005.133222.15797801841635819220.stgit@devnote2> <20240915044614.5721947e@rorschach.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240915044614.5721947e@rorschach.local.home> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240917_012632_627119_48D115A5 X-CRM114-Status: GOOD ( 15.84 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sun, Sep 15, 2024 at 04:46:14AM -0400, Steven Rostedt wrote: > Can I get an Acked-by from the AARCH64 maintainers for this patch? Sorry, I wasn't CC'd on the thread, so I missed this. > On Fri, 13 Sep 2024 00:08:40 +0900 > "Masami Hiramatsu (Google)" wrote: > > > From: Masami Hiramatsu (Google) > > > > Pass ftrace_regs to the fgraph_ops::entryfunc(). If ftrace_regs is not > > available, it passes a NULL instead. User callback function can access > > some registers (including return address) via this ftrace_regs. Under which circumstances is 'ftrace_regs' NULL? The arm64 implementation of ftrace_graph_func() is: > > diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c > > index a650f5e11fc5..bc647b725e6a 100644 > > --- a/arch/arm64/kernel/ftrace.c > > +++ b/arch/arm64/kernel/ftrace.c > > @@ -481,7 +481,25 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, > > void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, > > struct ftrace_ops *op, struct ftrace_regs *fregs) > > { > > - prepare_ftrace_return(ip, &fregs->lr, fregs->fp); > > + unsigned long return_hooker = (unsigned long)&return_to_handler; > > + unsigned long frame_pointer = fregs->fp; Which dereferences the unchecked pointer here ^^. Will