From patchwork Fri Feb 14 12:47:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 1238023 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 48JtXD1zQJz9sRN for ; Fri, 14 Feb 2020 23:50:36 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=c-s.fr header.i=@c-s.fr header.a=rsa-sha256 header.s=mail header.b=NkAUUNKo; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48JtXD1Lh1zDqbG for ; Fri, 14 Feb 2020 23:50:36 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=c-s.fr (client-ip=93.17.236.30; helo=pegase1.c-s.fr; envelope-from=christophe.leroy@c-s.fr; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=c-s.fr header.i=@c-s.fr header.a=rsa-sha256 header.s=mail header.b=NkAUUNKo; dkim-atps=neutral Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 48JtT75kPkzDqZS for ; Fri, 14 Feb 2020 23:47:54 +1100 (AEDT) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 48JtT05l5Nz9vCQl; Fri, 14 Feb 2020 13:47:48 +0100 (CET) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=NkAUUNKo; dkim-adsp=pass; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id efUaM-2d1a0F; Fri, 14 Feb 2020 13:47:48 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 48JtT04FJMz9vCQk; Fri, 14 Feb 2020 13:47:48 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1581684468; bh=3fiaA5FcWScVQJkSV4HPlPfihfk9MOHk1QtHl3KvFe4=; h=From:Subject:To:Cc:Date:From; b=NkAUUNKomt6tvLBELE+9DTFnFIgIts539Rh+tclNjXG0xYNuymK+xeeKZgA2r+TRH luzMoAi+FfNkoWkwLIHscsau1OuDErfa9yGjMpbWVAS/J1A8sr+/K7H0cWMnF4aOMM wKMgyrrF7mLRk4Ka4ceMI5xFUFHifyMlBlv4yv0Y= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id D54B78B898; Fri, 14 Feb 2020 13:47:49 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id 9H4XewX8cR8U; Fri, 14 Feb 2020 13:47:49 +0100 (CET) Received: from pc16570vm.idsi0.si.c-s.fr (po15451.idsi0.si.c-s.fr [172.25.230.102]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 804F18B897; Fri, 14 Feb 2020 13:47:49 +0100 (CET) Received: by pc16570vm.idsi0.si.c-s.fr (Postfix, from userid 0) id 4DAF0652FA; Fri, 14 Feb 2020 12:47:49 +0000 (UTC) Message-Id: From: Christophe Leroy Subject: [PATCH] powerpc/kprobes: Fix trap address when trap happened in real mode To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Larry Finger , Naveen N. Rao Date: Fri, 14 Feb 2020 12:47:49 +0000 (UTC) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, Anil S Keshavamurthy , stable@kernel.vger.org, Masami Hiramatsu , linuxppc-dev@lists.ozlabs.org, "David S. Miller" Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" When a program check exception happens while MMU translation is disabled, following Oops happens in kprobe_handler() in the following test: } else if (*addr != BREAKPOINT_INSTRUCTION) { [ 33.098554] BUG: Unable to handle kernel data access on read at 0x0000e268 [ 33.105091] Faulting instruction address: 0xc000ec34 [ 33.110010] Oops: Kernel access of bad area, sig: 11 [#1] [ 33.115348] BE PAGE_SIZE=16K PREEMPT CMPC885 [ 33.119540] Modules linked in: [ 33.122591] CPU: 0 PID: 429 Comm: cat Not tainted 5.6.0-rc1-s3k-dev-00824-g84195dc6c58a #3267 [ 33.131005] NIP: c000ec34 LR: c000ecd8 CTR: c019cab8 [ 33.136002] REGS: ca4d3b58 TRAP: 0300 Not tainted (5.6.0-rc1-s3k-dev-00824-g84195dc6c58a) [ 33.144324] MSR: 00001032 CR: 2a4d3c52 XER: 00000000 [ 33.150699] DAR: 0000e268 DSISR: c0000000 [ 33.150699] GPR00: c000b09c ca4d3c10 c66d0620 00000000 ca4d3c60 00000000 00009032 00000000 [ 33.150699] GPR08: 00020000 00000000 c087de44 c000afe0 c66d0ad0 100d3dd6 fffffff3 00000000 [ 33.150699] GPR16: 00000000 00000041 00000000 ca4d3d70 00000000 00000000 0000416d 00000000 [ 33.150699] GPR24: 00000004 c53b6128 00000000 0000e268 00000000 c07c0000 c07bb6fc ca4d3c60 [ 33.188015] NIP [c000ec34] kprobe_handler+0x128/0x290 [ 33.192989] LR [c000ecd8] kprobe_handler+0x1cc/0x290 [ 33.197854] Call Trace: [ 33.200340] [ca4d3c30] [c000b09c] program_check_exception+0xbc/0x6fc [ 33.206590] [ca4d3c50] [c000e43c] ret_from_except_full+0x0/0x4 [ 33.212392] --- interrupt: 700 at 0xe268 [ 33.270401] Instruction dump: [ 33.273335] 913e0008 81220000 38600001 3929ffff 91220000 80010024 bb410008 7c0803a6 [ 33.280992] 38210020 4e800020 38600000 4e800020 <813b0000> 6d2a7fe0 2f8a0008 419e0154 [ 33.288841] ---[ end trace 5b9152d4cdadd06d ]--- Check MSR and convert regs->nip to virtual address if the trap happened with MSR_IR cleared. Reported-by: Larry Finger Fixes: 6cc89bad60a6 ("powerpc/kprobes: Invoke handlers directly") Cc: stable@kernel.vger.org Cc: Naveen N. Rao Signed-off-by: Christophe Leroy --- The bug might have existed even before that commit from Naveen. Signed-off-by: Christophe Leroy --- arch/powerpc/kernel/kprobes.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 2d27ec4feee4..f8b848aa65bd 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -23,6 +23,7 @@ #include #include #include +#include #include DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; @@ -264,6 +265,9 @@ int kprobe_handler(struct pt_regs *regs) if (user_mode(regs)) return 0; + if (!(regs->msr & MSR_IR)) + addr = phys_to_virt(regs->nip); + /* * We don't want to be preempted for the entire * duration of kprobe processing