From patchwork Tue Sep 29 10:56:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 263070 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=-13.5 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, 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 179E8C4741F for ; Tue, 29 Sep 2020 12:13:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C38AB20759 for ; Tue, 29 Sep 2020 12:13:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601381592; bh=aBFx1KcBL6iJWVBlTWXIiK8c5LFnK4N15P9qCKDqaGg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YL3IM6cOJSGxsT/urRQibvwToiOKBFr6Hkay25o0RUE5cVCV9lmJYWr9jO0u4dePL 9AKHwdSzx4GJUYCCZw9TfLhnBkL0VQfpcQm5eZ1P9y7m3Bgj41IgP9oL85m7ZAQLMQ UDJsbqjGifBNIhUlcBmTUnkGVZ92wRuTHw5HPgbE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730960AbgI2MMv (ORCPT ); Tue, 29 Sep 2020 08:12:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:58104 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730133AbgI2Lha (ORCPT ); Tue, 29 Sep 2020 07:37:30 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 C508A23B97; Tue, 29 Sep 2020 11:34:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601379280; bh=aBFx1KcBL6iJWVBlTWXIiK8c5LFnK4N15P9qCKDqaGg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tIea4/qjei1J7REHcep/eb1Cn7AxK2F4jJz6ghu/c10IaVrMU119LOVkDphQJn78K yxCIPve8EgGBf/0Ub9/klXmnIH9jpa1MsR0oQBSwm70nzdWJ692OoRsPbSmyhjFqXw 1Lv70wncucvLPQbjJYBdNWukfA+zzendpGFCZL8s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Max Filippov , Sasha Levin Subject: [PATCH 5.4 063/388] xtensa: fix system_call interaction with ptrace Date: Tue, 29 Sep 2020 12:56:34 +0200 Message-Id: <20200929110013.548033987@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929110010.467764689@linuxfoundation.org> References: <20200929110010.467764689@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Max Filippov [ Upstream commit 02ce94c229251555ac726ecfebe3458ef5905fa9 ] Don't overwrite return value if system call was cancelled at entry by ptrace. Return status code from do_syscall_trace_enter so that pt_regs::syscall doesn't need to be changed to skip syscall. Signed-off-by: Max Filippov Signed-off-by: Sasha Levin --- arch/xtensa/kernel/entry.S | 4 ++-- arch/xtensa/kernel/ptrace.c | 18 ++++++++++++++++-- 2 files changed, 18 insertions(+), 4 deletions(-) diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S index 59671603c9c62..1f07876ea2ed7 100644 --- a/arch/xtensa/kernel/entry.S +++ b/arch/xtensa/kernel/entry.S @@ -1897,6 +1897,7 @@ ENTRY(system_call) mov a6, a2 call4 do_syscall_trace_enter + beqz a6, .Lsyscall_exit l32i a7, a2, PT_SYSCALL 1: @@ -1911,8 +1912,6 @@ ENTRY(system_call) addx4 a4, a7, a4 l32i a4, a4, 0 - movi a5, sys_ni_syscall; - beq a4, a5, 1f /* Load args: arg0 - arg5 are passed via regs. */ @@ -1932,6 +1931,7 @@ ENTRY(system_call) s32i a6, a2, PT_AREG2 bnez a3, 1f +.Lsyscall_exit: abi_ret(4) 1: diff --git a/arch/xtensa/kernel/ptrace.c b/arch/xtensa/kernel/ptrace.c index b964f0b2d8864..145742d70a9f2 100644 --- a/arch/xtensa/kernel/ptrace.c +++ b/arch/xtensa/kernel/ptrace.c @@ -542,14 +542,28 @@ long arch_ptrace(struct task_struct *child, long request, return ret; } -void do_syscall_trace_enter(struct pt_regs *regs) +void do_syscall_trace_leave(struct pt_regs *regs); +int do_syscall_trace_enter(struct pt_regs *regs) { + if (regs->syscall == NO_SYSCALL) + regs->areg[2] = -ENOSYS; + if (test_thread_flag(TIF_SYSCALL_TRACE) && - tracehook_report_syscall_entry(regs)) + tracehook_report_syscall_entry(regs)) { + regs->areg[2] = -ENOSYS; regs->syscall = NO_SYSCALL; + return 0; + } + + if (regs->syscall == NO_SYSCALL) { + do_syscall_trace_leave(regs); + return 0; + } if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) trace_sys_enter(regs, syscall_get_nr(current, regs)); + + return 1; } void do_syscall_trace_leave(struct pt_regs *regs)