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=-16.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 0F11AC433C1 for ; Sat, 20 Mar 2021 12:16:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C937E61973 for ; Sat, 20 Mar 2021 12:16:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229686AbhCTMQY (ORCPT ); Sat, 20 Mar 2021 08:16:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:37036 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229607AbhCTMQX (ORCPT ); Sat, 20 Mar 2021 08:16:23 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 59F4D61967; Sat, 20 Mar 2021 12:16:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1616242583; bh=L6kTH0jPnKRJ0H6xWkNVyPWe1UOUc18Ymagil4Ig+YU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=f4h9j8C3aQFdXsU1QceNHEE7rfxMBcj3EBvTJrm7UtrFwAzmIQpJm98cKrsgrnkzU bf4aI+QQMsMaJvzlv2b5Inzjil1j8A8kFXijRBa0vF5gaPWKbqhVLFNpMo5lmzKKWr nJJ/ItwVCkSK+RlH00aDKMdcpXjdGudh/q0/TK/cG69PT/lGnVbCS1+XjQFdl1l+t9 lJ/fC4rq65sAyneWRiu6adkgT9pyhgF+zpKXAzySDMi6ErDVAs/YvkbBz6zepKv/V0 ssT+K5KWx+Dqlu2FKJFmTsS3m5/LAoxbKGIzncELs4YJl+H/GhR9fyx9y2FZt7RoOF yk18YMeYaElUw== Date: Sat, 20 Mar 2021 21:16:16 +0900 From: Masami Hiramatsu To: Masami Hiramatsu Cc: Steven Rostedt , Ingo Molnar , X86 ML , Daniel Xu , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, kuba@kernel.org, mingo@redhat.com, ast@kernel.org, tglx@linutronix.de, kernel-team@fb.com, yhs@fb.com, Josh Poimboeuf , linux-ia64@vger.kernel.org Subject: Re: [PATCH -tip v3 05/11] x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline code Message-Id: <20210320211616.a976fc66d0c51e13d3121e2f@kernel.org> In-Reply-To: <161615655969.306069.4545805781593088526.stgit@devnote2> References: <161615650355.306069.17260992641363840330.stgit@devnote2> <161615655969.306069.4545805781593088526.stgit@devnote2> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Fri, 19 Mar 2021 21:22:39 +0900 Masami Hiramatsu wrote: > From: Josh Poimboeuf > > Add UNWIND_HINT_FUNC on kretporbe_trampoline code so that ORC > information is generated on the kretprobe_trampoline correctly. > Test bot also found a new warning for this. > >> arch/x86/kernel/kprobes/core.o: warning: objtool: kretprobe_trampoline()+0x25: call without frame pointer save/setup With CONFIG_FRAME_POINTER=y. Of course this can be fixed with additional "push %bp; mov %sp, %bp" before calling trampoline_handler. But actually we know that this function has a bit special stack frame too. Can I recover STACK_FRAME_NON_STANDARD(kretprobe_trampoline) when CONFIG_FRAME_POINTER=y ? Thank you, > Signed-off-by: Josh Poimboeuf > --- > [MH] Add patch description. > --- > arch/x86/include/asm/unwind_hints.h | 5 +++++ > arch/x86/kernel/kprobes/core.c | 3 ++- > 2 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/include/asm/unwind_hints.h b/arch/x86/include/asm/unwind_hints.h > index 8e574c0afef8..8b33674288ea 100644 > --- a/arch/x86/include/asm/unwind_hints.h > +++ b/arch/x86/include/asm/unwind_hints.h > @@ -52,6 +52,11 @@ > UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=8 type=UNWIND_HINT_TYPE_FUNC > .endm > > +#else > + > +#define UNWIND_HINT_FUNC \ > + UNWIND_HINT(ORC_REG_SP, 8, UNWIND_HINT_TYPE_FUNC, 0) > + > #endif /* __ASSEMBLY__ */ > > #endif /* _ASM_X86_UNWIND_HINTS_H */ > diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c > index 427d648fffcd..b31058a152b6 100644 > --- a/arch/x86/kernel/kprobes/core.c > +++ b/arch/x86/kernel/kprobes/core.c > @@ -772,6 +772,7 @@ asm( > /* We don't bother saving the ss register */ > #ifdef CONFIG_X86_64 > " pushq %rsp\n" > + UNWIND_HINT_FUNC > " pushfq\n" > SAVE_REGS_STRING > " movq %rsp, %rdi\n" > @@ -782,6 +783,7 @@ asm( > " popfq\n" > #else > " pushl %esp\n" > + UNWIND_HINT_FUNC > " pushfl\n" > SAVE_REGS_STRING > " movl %esp, %eax\n" > @@ -795,7 +797,6 @@ asm( > ".size kretprobe_trampoline, .-kretprobe_trampoline\n" > ); > NOKPROBE_SYMBOL(kretprobe_trampoline); > -STACK_FRAME_NON_STANDARD(kretprobe_trampoline); > > > /* > -- Masami Hiramatsu