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 CBCB22905; Tue, 17 Sep 2024 08:26:31 +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=1726561591; cv=none; b=b0QJZ+7PRHYR/TnwKbAafYM696n+HWYZStVVdkhfrGSnd3iIiD70CyyEjzQhTx3wDI0Izi9QQ0aaZmFTxXzE0y21JY1MkAEDigj931zw5f3l3foyUzNnQdoI14ylAVRc8HV9mLo3QlmPP7cDBfjZ26LWkT32ggMDT4Q//FLJ/1I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726561591; c=relaxed/simple; bh=yX8WybCaNIWhzTkbjSWRx9jTOwkDZkYTQGTxrYRDcI4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kgsECLyn9eMKdaeE5kmFgA1hHtZTUSQ9KEYdwwMevbascEekpqECZhiy8ckckDzb0h0g6nuf/nnyPyVrFgV9O8yDYFq8+jtCzJuXFTZFyLVHWQ8iFm5W2d5FsphsusSOXLyOFSBzgYlu+NpZJ9SI63tUKz2N9PRQMsI9Yf+CxGg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rifoRMQL; 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="rifoRMQL" 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> 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-Disposition: inline In-Reply-To: <20240915044614.5721947e@rorschach.local.home> User-Agent: Mutt/1.10.1 (2018-07-13) 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