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 X-Spam-Level: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A4DFC07E9B for ; Mon, 5 Jul 2021 11:37:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7645E613C8 for ; Mon, 5 Jul 2021 11:37:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231403AbhGELkO (ORCPT ); Mon, 5 Jul 2021 07:40:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231286AbhGELkO (ORCPT ); Mon, 5 Jul 2021 07:40:14 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 761D3C061574; Mon, 5 Jul 2021 04:37:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=CtwriWiKNwEyPS7wLGosDrs1cNvFIMaj7va3rpRQQIg=; b=tmtzEHW3+X0tS77m9YJ9iqG4hq KZ6c5b4LQxTd/0FbCgReItHmXkmQXz+fVrK/XAThajPegKRWxD3+QLJE7XIuP054SYCBp5HRgsSrt Krevd8NbRA3zaGwAEgi82jX1FzhtGyoXk2aC1FvLF7lPN1uIiEqFdOoikHiKE3HHyX4iIdIPH48Iz XXOJIYcyJQIPz43O3BoIr1qmaNp6chmnlZGGCNNCSe/9vspoOMBEbME/WiysvjKHhpPhyJZIqQjKC I4E0mb+HraGyZUN8qj3mgIY97Q/y97pDFmYzdb5UZLgh6RnGaqzDrviBlUZrbB3dmfJ+HiuT5DfVO hoWLslYQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1m0Mtd-00ACWy-27; Mon, 05 Jul 2021 11:36:20 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id C2C3E3001DC; Mon, 5 Jul 2021 13:36:14 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 5F23A200E1E64; Mon, 5 Jul 2021 13:36:14 +0200 (CEST) Date: Mon, 5 Jul 2021 13:36:14 +0200 From: Peter Zijlstra To: Masami Hiramatsu Cc: Steven Rostedt , Josh Poimboeuf , Ingo Molnar , X86 ML , Daniel Xu , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, kuba@kernel.org, mingo@redhat.com, ast@kernel.org, Thomas Gleixner , Borislav Petkov , kernel-team@fb.com, yhs@fb.com, linux-ia64@vger.kernel.org, Abhishek Sagar , Andrii Nakryiko Subject: Re: [PATCH -tip v8 11/13] x86/unwind: Recover kretprobe trampoline entry Message-ID: References: <162399992186.506599.8457763707951687195.stgit@devnote2> <162400002631.506599.2413605639666466945.stgit@devnote2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <162400002631.506599.2413605639666466945.stgit@devnote2> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 18, 2021 at 04:07:06PM +0900, Masami Hiramatsu wrote: > @@ -549,7 +548,15 @@ bool unwind_next_frame(struct unwind_state *state) > (void *)orig_ip); > goto err; > } > - > + /* > + * There is a small chance to interrupt at the entry of > + * kretprobe_trampoline where the ORC info doesn't exist. > + * That point is right after the RET to kretprobe_trampoline > + * which was modified return address. So the @addr_p must > + * be right before the regs->sp. > + */ > + state->ip = unwind_recover_kretprobe(state, state->ip, > + (unsigned long *)(state->sp - sizeof(long))); > state->regs = (struct pt_regs *)sp; > state->prev_regs = NULL; > state->full_regs = true; > @@ -562,6 +569,9 @@ bool unwind_next_frame(struct unwind_state *state) > (void *)orig_ip); > goto err; > } > + /* See UNWIND_HINT_TYPE_REGS case comment. */ > + state->ip = unwind_recover_kretprobe(state, state->ip, > + (unsigned long *)(state->sp - sizeof(long))); > > if (state->full_regs) > state->prev_regs = state->regs; Why doesn't the ftrace case have this? That is, why aren't both return trampolines having the same general shape?