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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 DFF11C32750 for ; Fri, 2 Aug 2019 10:01:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B64D42064A for ; Fri, 2 Aug 2019 10:01:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564740064; bh=MW5r1T5Jv+fgOBh4dB5YLMTC+scbJI543u0fy1TGH+U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=yZ6drimNp0yJzsxpr8+uO2hzTYfqK71a1y1TxFu7l9Y8N4tCfwfYqnoWvhE0+ZeoR hOmR/0p85oabKSKEsAowhaZnbDKdW2L1Htj6q6i9RbkcZZPfI7jLpyfdijTf6MfrHb oVD9Fhd5mjandSpBsmf+eE7+ol/It2GsLceww3vQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2407067AbfHBKBD (ORCPT ); Fri, 2 Aug 2019 06:01:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:56940 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405655AbfHBJvi (ORCPT ); Fri, 2 Aug 2019 05:51:38 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5C4D020B7C; Fri, 2 Aug 2019 09:51:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564739497; bh=MW5r1T5Jv+fgOBh4dB5YLMTC+scbJI543u0fy1TGH+U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yCw8i8AqDI55SF7o6JUEEcrKE7mk4hHe/oi6U1cfT+NtDXgdw68Yqz+Br76ZAOpg3 Hkg9PrQmjl8qHftHNZYnh4ru70+aHATO4yQuWY5ZTUNUcmJAsVFU4HJfWd4paT+B/A L//u3JjwoRFFDcv3aCOQ7Uj9af4AOyZGehl6tq7I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Naveen N. Rao" , "Steven Rostedt (VMware)" , Satheesh Rajendran , Michael Ellerman , Sasha Levin Subject: [PATCH 4.9 180/223] recordmcount: Fix spurious mcount entries on powerpc Date: Fri, 2 Aug 2019 11:36:45 +0200 Message-Id: <20190802092249.350290510@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190802092238.692035242@linuxfoundation.org> References: <20190802092238.692035242@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 80e5302e4bc85a6b685b7668c36c6487b5f90e9a ] An impending change to enable HAVE_C_RECORDMCOUNT on powerpc leads to warnings such as the following: # modprobe kprobe_example ftrace-powerpc: Not expected bl: opcode is 3c4c0001 WARNING: CPU: 0 PID: 227 at kernel/trace/ftrace.c:2001 ftrace_bug+0x90/0x318 Modules linked in: CPU: 0 PID: 227 Comm: modprobe Not tainted 5.2.0-rc6-00678-g1c329100b942 #2 NIP: c000000000264318 LR: c00000000025d694 CTR: c000000000f5cd30 REGS: c000000001f2b7b0 TRAP: 0700 Not tainted (5.2.0-rc6-00678-g1c329100b942) MSR: 900000010282b033 CR: 28228222 XER: 00000000 CFAR: c0000000002642fc IRQMASK: 0 NIP [c000000000264318] ftrace_bug+0x90/0x318 LR [c00000000025d694] ftrace_process_locs+0x4f4/0x5e0 Call Trace: [c000000001f2ba40] [0000000000000004] 0x4 (unreliable) [c000000001f2bad0] [c00000000025d694] ftrace_process_locs+0x4f4/0x5e0 [c000000001f2bb90] [c00000000020ff10] load_module+0x25b0/0x30c0 [c000000001f2bd00] [c000000000210cb0] sys_finit_module+0xc0/0x130 [c000000001f2be20] [c00000000000bda4] system_call+0x5c/0x70 Instruction dump: 419e0018 2f83ffff 419e00bc 2f83ffea 409e00cc 4800001c 0fe00000 3c62ff96 39000001 39400000 386386d0 480000c4 <0fe00000> 3ce20003 39000001 3c62ff96 ---[ end trace 4c438d5cebf78381 ]--- ftrace failed to modify [] 0xc0080000012a0008 actual: 01:00:4c:3c Initializing ftrace call sites ftrace record flags: 2000000 (0) expected tramp: c00000000006af4c Looking at the relocation records in __mcount_loc shows a few spurious entries: RELOCATION RECORDS FOR [__mcount_loc]: OFFSET TYPE VALUE 0000000000000000 R_PPC64_ADDR64 .text.unlikely+0x0000000000000008 0000000000000008 R_PPC64_ADDR64 .text.unlikely+0x0000000000000014 0000000000000010 R_PPC64_ADDR64 .text.unlikely+0x0000000000000060 0000000000000018 R_PPC64_ADDR64 .text.unlikely+0x00000000000000b4 0000000000000020 R_PPC64_ADDR64 .init.text+0x0000000000000008 0000000000000028 R_PPC64_ADDR64 .init.text+0x0000000000000014 The first entry in each section is incorrect. Looking at the relocation records, the spurious entries correspond to the R_PPC64_ENTRY records: RELOCATION RECORDS FOR [.text.unlikely]: OFFSET TYPE VALUE 0000000000000000 R_PPC64_REL64 .TOC.-0x0000000000000008 0000000000000008 R_PPC64_ENTRY *ABS* 0000000000000014 R_PPC64_REL24 _mcount The problem is that we are not validating the return value from get_mcountsym() in sift_rel_mcount(). With this entry, mcountsym is 0, but Elf_r_sym(relp) also ends up being 0. Fix this by ensuring mcountsym is valid before processing the entry. Signed-off-by: Naveen N. Rao Acked-by: Steven Rostedt (VMware) Tested-by: Satheesh Rajendran Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin --- scripts/recordmcount.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h index b9897e2be404..04151ede8043 100644 --- a/scripts/recordmcount.h +++ b/scripts/recordmcount.h @@ -326,7 +326,8 @@ static uint_t *sift_rel_mcount(uint_t *mlocp, if (!mcountsym) mcountsym = get_mcountsym(sym0, relp, str0); - if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) { + if (mcountsym && mcountsym == Elf_r_sym(relp) && + !is_fake_mcount(relp)) { uint_t const addend = _w(_w(relp->r_offset) - recval + mcount_adjust); mrelp->r_offset = _w(offbase -- 2.20.1