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=-13.0 required=3.0 tests=BAYES_00,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 A8DA3C433E6 for ; Tue, 14 Jul 2020 19:11:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 87C7922507 for ; Tue, 14 Jul 2020 19:11:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594753919; bh=YrBst1bQgUd+Gjzd8v6dDWmG1vhFrTrycU3s+vHJksA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lKC2sWttLc1COKUxAdOaGkuKyYP6u9YT3Fsaeac3LbNsxsK2BeUo06v0MbO+9YoVB auNeYqmQ4c+IbvHh8RLqoN7gFn+771QbiZ4hjeLT/PxlZlyHCEUDxB1PP2QH2Xf5tI YZSpSh9t0Rh+0bNq+ET0xieGxfJcPMvMQoQdGmnc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729992AbgGNTLw (ORCPT ); Tue, 14 Jul 2020 15:11:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:43550 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729325AbgGNSsM (ORCPT ); Tue, 14 Jul 2020 14:48:12 -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 70E2B22AAA; Tue, 14 Jul 2020 18:48:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594752492; bh=YrBst1bQgUd+Gjzd8v6dDWmG1vhFrTrycU3s+vHJksA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=K86IyglDJM/kj0vr62YkBO3XVOF9dJac1cRvohx7zGq5o2ZPz9FW6HwAss4c2bdaW Yf6DOcJRhiMi0T2icnN4yt+zonLcHGvmxJODqIG7SADN413CfEBfVZ7lvA14xlVrY+ C5BDuPM010q9UB3+15Glqk7BEeozj1hOsdD/3bBU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wei Li , Douglas Anderson , Will Deacon , Sasha Levin Subject: [PATCH 4.19 32/58] arm64: kgdb: Fix single-step exception handling oops Date: Tue, 14 Jul 2020 20:44:05 +0200 Message-Id: <20200714184057.731003031@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200714184056.149119318@linuxfoundation.org> References: <20200714184056.149119318@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Wei Li [ Upstream commit 8523c006264df65aac7d77284cc69aac46a6f842 ] After entering kdb due to breakpoint, when we execute 'ss' or 'go' (will delay installing breakpoints, do single-step first), it won't work correctly, and it will enter kdb due to oops. It's because the reason gotten in kdb_stub() is not as expected, and it seems that the ex_vector for single-step should be 0, like what arch powerpc/sh/parisc has implemented. Before the patch: Entering kdb (current=0xffff8000119e2dc0, pid 0) on processor 0 due to Keyboard Entry [0]kdb> bp printk Instruction(i) BP #0 at 0xffff8000101486cc (printk) is enabled addr at ffff8000101486cc, hardtype=0 installed=0 [0]kdb> g / # echo h > /proc/sysrq-trigger Entering kdb (current=0xffff0000fa878040, pid 266) on processor 3 due to Breakpoint @ 0xffff8000101486cc [3]kdb> ss Entering kdb (current=0xffff0000fa878040, pid 266) on processor 3 Oops: (null) due to oops @ 0xffff800010082ab8 CPU: 3 PID: 266 Comm: sh Not tainted 5.7.0-rc4-13839-gf0e5ad491718 #6 Hardware name: linux,dummy-virt (DT) pstate: 00000085 (nzcv daIf -PAN -UAO) pc : el1_irq+0x78/0x180 lr : __handle_sysrq+0x80/0x190 sp : ffff800015003bf0 x29: ffff800015003d20 x28: ffff0000fa878040 x27: 0000000000000000 x26: ffff80001126b1f0 x25: ffff800011b6a0d8 x24: 0000000000000000 x23: 0000000080200005 x22: ffff8000101486cc x21: ffff800015003d30 x20: 0000ffffffffffff x19: ffff8000119f2000 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000 x8 : ffff800015003e50 x7 : 0000000000000002 x6 : 00000000380b9990 x5 : ffff8000106e99e8 x4 : ffff0000fadd83c0 x3 : 0000ffffffffffff x2 : ffff800011b6a0d8 x1 : ffff800011b6a000 x0 : ffff80001130c9d8 Call trace: el1_irq+0x78/0x180 printk+0x0/0x84 write_sysrq_trigger+0xb0/0x118 proc_reg_write+0xb4/0xe0 __vfs_write+0x18/0x40 vfs_write+0xb0/0x1b8 ksys_write+0x64/0xf0 __arm64_sys_write+0x14/0x20 el0_svc_common.constprop.2+0xb0/0x168 do_el0_svc+0x20/0x98 el0_sync_handler+0xec/0x1a8 el0_sync+0x140/0x180 [3]kdb> After the patch: Entering kdb (current=0xffff8000119e2dc0, pid 0) on processor 0 due to Keyboard Entry [0]kdb> bp printk Instruction(i) BP #0 at 0xffff8000101486cc (printk) is enabled addr at ffff8000101486cc, hardtype=0 installed=0 [0]kdb> g / # echo h > /proc/sysrq-trigger Entering kdb (current=0xffff0000fa852bc0, pid 268) on processor 0 due to Breakpoint @ 0xffff8000101486cc [0]kdb> g Entering kdb (current=0xffff0000fa852bc0, pid 268) on processor 0 due to Breakpoint @ 0xffff8000101486cc [0]kdb> ss Entering kdb (current=0xffff0000fa852bc0, pid 268) on processor 0 due to SS trap @ 0xffff800010082ab8 [0]kdb> Fixes: 44679a4f142b ("arm64: KGDB: Add step debugging support") Signed-off-by: Wei Li Tested-by: Douglas Anderson Reviewed-by: Douglas Anderson Link: https://lore.kernel.org/r/20200509214159.19680-2-liwei391@huawei.com Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/kernel/kgdb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/kgdb.c b/arch/arm64/kernel/kgdb.c index 35f184a8fd85a..8815b5457dd0b 100644 --- a/arch/arm64/kernel/kgdb.c +++ b/arch/arm64/kernel/kgdb.c @@ -269,7 +269,7 @@ static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned int esr) if (user_mode(regs) || !kgdb_single_step) return DBG_HOOK_ERROR; - kgdb_handle_exception(1, SIGTRAP, 0, regs); + kgdb_handle_exception(0, SIGTRAP, 0, regs); return DBG_HOOK_HANDLED; } NOKPROBE_SYMBOL(kgdb_step_brk_fn); -- 2.25.1