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=-8.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 5FFFCC04AB6 for ; Tue, 28 May 2019 12:30:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3612A20989 for ; Tue, 28 May 2019 12:30:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="DwR7hrH4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727105AbfE1MaW (ORCPT ); Tue, 28 May 2019 08:30:22 -0400 Received: from mail-pf1-f196.google.com ([209.85.210.196]:40355 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726592AbfE1MaW (ORCPT ); Tue, 28 May 2019 08:30:22 -0400 Received: by mail-pf1-f196.google.com with SMTP id u17so11394199pfn.7 for ; Tue, 28 May 2019 05:30:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=wbDGMNbYYQdX+Pxgd0vXZtreujx15Q0l3ZduS6F2GKM=; b=DwR7hrH4XP5l1bRLMyG3fcNleGVYoVC/tS84AWJhif6ykzugPG+ekI1PwCGTXaDGO8 iTfiaOapH9jFQ7MnE8/KcTEt2ffoZKpH7zOQc/D4xQnLu+E4LZ9z9KEMZjrfbXCtiqvi dXSo0KyVluHT4kR9p4Riuh7neCVjt4H6ufTo9SAZdKNFKDi6TGRnISCWIPDa0LxGrR5t u0dFfncicOOMqrvABG40tZX2m1uKuzIPunjA4FE+mpJpSuDhT8XckfWZ/xkxmOU4Bw3z Ri/A/ZUxxMQV4cVycg9pQb2xP9SncyAkEvNCfbSLdx2Gh8LkL2w32g2uPcUiV7kODABg EqNQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=wbDGMNbYYQdX+Pxgd0vXZtreujx15Q0l3ZduS6F2GKM=; b=SqgzMWfY801uHi3fmZR5hAnYHoMUiUqSFM/Ti1MeUTAHnbYNZXAqYhmvCzXchrRwWs 1IwiPSjjwV9fTGILpfTGRdFD6qKya+8100BCpuTf4FvClEHkDZYwmczUhkT/lMtwQz5d Sqo6nZNjSRrFvITih5gNOI2TKt2gPuDvvxoLd8WjB5YYQigQXcVl+8/j7cWnHCZeXYcN 0X4HXT4Cx9PMGY6ezsXUrc4Dfi1dNd34TrornPZO7HNmpzqmqfPKQ/ffJpgTmmh5R6cy FCirIaImcvq6f41UHMYddTYEbC+GHd1ebM6ImNqIFwqcR6XLOhXzsgB+51snhRiu5GJd zeaQ== X-Gm-Message-State: APjAAAU067FXkeRwHz4eoytGJasjHIfTAG5fIthxFy802ib6HaEUyude rh2iovueHYiG6OGz9IA/sIA= X-Google-Smtp-Source: APXvYqwWncBkj10LXWl+MumT21W1v1+iisFqPYQvOkVpMdzhh53zR0Fpx8rd0FLH6RVrACMt4bE7ow== X-Received: by 2002:a62:ab0a:: with SMTP id p10mr44367366pff.143.1559046621476; Tue, 28 May 2019 05:30:21 -0700 (PDT) Received: from xy-data.openstacklocal (ecs-159-138-22-150.compute.hwclouds-dns.com. [159.138.22.150]) by smtp.gmail.com with ESMTPSA id y12sm1434787pgi.10.2019.05.28.05.30.18 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 28 May 2019 05:30:20 -0700 (PDT) From: Young Xiao <92siuyang@gmail.com> To: will.deacon@arm.com, linux@armlinux.org.uk, mark.rutland@arm.com, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, peterz@infradead.org, kan.liang@linux.intel.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Young Xiao <92siuyang@gmail.com> Subject: [PATCH] perf: Fix oops when kthread execs user process Date: Tue, 28 May 2019 20:31:29 +0800 Message-Id: <1559046689-24091-1-git-send-email-92siuyang@gmail.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When a kthread calls call_usermodehelper() the steps are: 1. allocate current->mm 2. load_elf_binary() 3. populate current->thread.regs While doing this, interrupts are not disabled. If there is a perf interrupt in the middle of this process (i.e. step 1 has completed but not yet reached to step 3) and if perf tries to read userspace regs, kernel oops. Fix it by setting abi to PERF_SAMPLE_REGS_ABI_NONE when userspace pt_regs are not set. See commit bf05fc25f268 ("powerpc/perf: Fix oops when kthread execs user process") for details. Signed-off-by: Young Xiao <92siuyang@gmail.com> --- arch/arm/kernel/perf_regs.c | 3 ++- arch/arm64/kernel/perf_regs.c | 3 ++- arch/x86/kernel/perf_regs.c | 3 ++- 3 files changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/arm/kernel/perf_regs.c b/arch/arm/kernel/perf_regs.c index 05fe92a..78ee29a 100644 --- a/arch/arm/kernel/perf_regs.c +++ b/arch/arm/kernel/perf_regs.c @@ -36,5 +36,6 @@ void perf_get_regs_user(struct perf_regs *regs_user, struct pt_regs *regs_user_copy) { regs_user->regs = task_pt_regs(current); - regs_user->abi = perf_reg_abi(current); + regs_user->abi = (regs_user->regs) ? perf_reg_abi(current) : + PERF_SAMPLE_REGS_ABI_NONE; } diff --git a/arch/arm64/kernel/perf_regs.c b/arch/arm64/kernel/perf_regs.c index 0bbac61..ac19d19 100644 --- a/arch/arm64/kernel/perf_regs.c +++ b/arch/arm64/kernel/perf_regs.c @@ -58,5 +58,6 @@ void perf_get_regs_user(struct perf_regs *regs_user, struct pt_regs *regs_user_copy) { regs_user->regs = task_pt_regs(current); - regs_user->abi = perf_reg_abi(current); + regs_user->abi = (regs_user->regs) ? perf_reg_abi(current) : + PERF_SAMPLE_REGS_ABI_NONE; } diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c index 07c30ee..fa79d6d 100644 --- a/arch/x86/kernel/perf_regs.c +++ b/arch/x86/kernel/perf_regs.c @@ -102,7 +102,8 @@ void perf_get_regs_user(struct perf_regs *regs_user, struct pt_regs *regs_user_copy) { regs_user->regs = task_pt_regs(current); - regs_user->abi = perf_reg_abi(current); + regs_user->abi = (regs_user->regs) ? perf_reg_abi(current) : + PERF_SAMPLE_REGS_ABI_NONE; } #else /* CONFIG_X86_64 */ #define REG_NOSUPPORT ((1ULL << PERF_REG_X86_DS) | \ -- 2.7.4