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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B5460C433F5 for ; Wed, 9 Mar 2022 16:44:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235811AbiCIQpn (ORCPT ); Wed, 9 Mar 2022 11:45:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238527AbiCIQb2 (ORCPT ); Wed, 9 Mar 2022 11:31:28 -0500 Received: from out01.mta.xmission.com (out01.mta.xmission.com [166.70.13.231]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 44B4B198D08 for ; Wed, 9 Mar 2022 08:25:54 -0800 (PST) Received: from in02.mta.xmission.com ([166.70.13.52]:59198) by out01.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nRz8C-008XNf-6v; Wed, 09 Mar 2022 09:25:44 -0700 Received: from ip68-227-174-4.om.om.cox.net ([68.227.174.4]:34572 helo=localhost.localdomain) by in02.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nRz8A-005hAS-Qt; Wed, 09 Mar 2022 09:25:43 -0700 From: "Eric W. Biederman" To: linux-kernel@vger.kernel.org Cc: Linus Torvalds , Alexey Gladkov , Kyle Huey , Oleg Nesterov , Kees Cook , Al Viro , Jens Axboe , "Eric W. Biederman" Date: Wed, 9 Mar 2022 10:24:49 -0600 Message-Id: <20220309162454.123006-8-ebiederm@xmission.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <87o82gdlu9.fsf_-_@email.froward.int.ebiederm.org> References: <87o82gdlu9.fsf_-_@email.froward.int.ebiederm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-XM-SPF: eid=1nRz8A-005hAS-Qt;;;mid=<20220309162454.123006-8-ebiederm@xmission.com>;;;hst=in02.mta.xmission.com;;;ip=68.227.174.4;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19MKYPBZsajzhiI7hSBuOQxerVPDJ+Pj64= X-SA-Exim-Connect-IP: 68.227.174.4 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 08/13] task_work: Call tracehook_notify_signal from get_signal on all architectures X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Always handle TIF_NOTIFY_SIGNAL in get_signal. With commit 35d0b389f3b2 ("task_work: unconditionally run task_work from get_signal()") always calling task_wofffffffrk_run all of the work of tracehook_notify_signal is already happening except clearing TIF_NOTIFY_SIGNAL. Factor clear_notify_signal out of tracehook_notify_signal and use it in get_signal so that get_signal only needs one call of trask_work_run. To keep the semantics in sync update xfer_to_guest_mode_work (which does not call get_signal) to call tracehook_notify_signal if either _TIF_SIGPENDING or _TIF_NOTIFY_SIGNAL. Signed-off-by: "Eric W. Biederman" --- arch/s390/kernel/signal.c | 4 ++-- arch/x86/kernel/signal.c | 4 ++-- include/linux/entry-common.h | 2 +- include/linux/tracehook.h | 9 +++++++-- kernel/entry/common.c | 12 ++---------- kernel/entry/kvm.c | 2 +- kernel/signal.c | 14 +++----------- 7 files changed, 18 insertions(+), 29 deletions(-) diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c index 307f5d99514d..ea9e5e8182cd 100644 --- a/arch/s390/kernel/signal.c +++ b/arch/s390/kernel/signal.c @@ -453,7 +453,7 @@ static void handle_signal(struct ksignal *ksig, sigset_t *oldset, * stack-frames in one go after that. */ -void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal) +void arch_do_signal_or_restart(struct pt_regs *regs) { struct ksignal ksig; sigset_t *oldset = sigmask_to_save(); @@ -466,7 +466,7 @@ void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal) current->thread.system_call = test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0; - if (has_signal && get_signal(&ksig)) { + if (get_signal(&ksig)) { /* Whee! Actually deliver the signal. */ if (current->thread.system_call) { regs->int_code = current->thread.system_call; diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index ec71e06ae364..de3d5b5724d8 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -861,11 +861,11 @@ static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs) * want to handle. Thus you cannot kill init even with a SIGKILL even by * mistake. */ -void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal) +void arch_do_signal_or_restart(struct pt_regs *regs) { struct ksignal ksig; - if (has_signal && get_signal(&ksig)) { + if (get_signal(&ksig)) { /* Whee! Actually deliver the signal. */ handle_signal(&ksig, regs); return; diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index 9efbdda61f7a..3537fd25f14e 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -257,7 +257,7 @@ static __always_inline void arch_exit_to_user_mode(void) { } * * Invoked from exit_to_user_mode_loop(). */ -void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal); +void arch_do_signal_or_restart(struct pt_regs *regs); /** * exit_to_user_mode - Fixup state when exiting to user mode diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index fa834a22e86e..b44a7820c468 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -106,6 +106,12 @@ static inline void tracehook_notify_resume(struct pt_regs *regs) rseq_handle_notify_resume(NULL, regs); } +static inline void clear_notify_signal(void) +{ + clear_thread_flag(TIF_NOTIFY_SIGNAL); + smp_mb__after_atomic(); +} + /* * called by exit_to_user_mode_loop() if ti_work & _TIF_NOTIFY_SIGNAL. This * is currently used by TWA_SIGNAL based task_work, which requires breaking @@ -113,8 +119,7 @@ static inline void tracehook_notify_resume(struct pt_regs *regs) */ static inline void tracehook_notify_signal(void) { - clear_thread_flag(TIF_NOTIFY_SIGNAL); - smp_mb__after_atomic(); + clear_notify_signal(); if (task_work_pending(current)) task_work_run(); } diff --git a/kernel/entry/common.c b/kernel/entry/common.c index f0b1daa1e8da..79eaf9b4b10d 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -139,15 +139,7 @@ void noinstr exit_to_user_mode(void) } /* Workaround to allow gradual conversion of architecture code */ -void __weak arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal) { } - -static void handle_signal_work(struct pt_regs *regs, unsigned long ti_work) -{ - if (ti_work & _TIF_NOTIFY_SIGNAL) - tracehook_notify_signal(); - - arch_do_signal_or_restart(regs, ti_work & _TIF_SIGPENDING); -} +void __weak arch_do_signal_or_restart(struct pt_regs *regs) { } static unsigned long exit_to_user_mode_loop(struct pt_regs *regs, unsigned long ti_work) @@ -170,7 +162,7 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs, klp_update_patch_state(current); if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) - handle_signal_work(regs, ti_work); + arch_do_signal_or_restart(regs); if (ti_work & _TIF_NOTIFY_RESUME) tracehook_notify_resume(regs); diff --git a/kernel/entry/kvm.c b/kernel/entry/kvm.c index 96d476e06c77..cabf36a489e4 100644 --- a/kernel/entry/kvm.c +++ b/kernel/entry/kvm.c @@ -8,7 +8,7 @@ static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work) do { int ret; - if (ti_work & _TIF_NOTIFY_SIGNAL) + if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) tracehook_notify_signal(); if (ti_work & _TIF_SIGPENDING) { diff --git a/kernel/signal.c b/kernel/signal.c index 3b4cf25fb9b3..8632b88982c9 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2626,20 +2626,12 @@ bool get_signal(struct ksignal *ksig) struct signal_struct *signal = current->signal; int signr; + clear_notify_signal(); if (unlikely(task_work_pending(current))) task_work_run(); - /* - * For non-generic architectures, check for TIF_NOTIFY_SIGNAL so - * that the arch handlers don't all have to do it. If we get here - * without TIF_SIGPENDING, just exit after running signal work. - */ - if (!IS_ENABLED(CONFIG_GENERIC_ENTRY)) { - if (test_thread_flag(TIF_NOTIFY_SIGNAL)) - tracehook_notify_signal(); - if (!task_sigpending(current)) - return false; - } + if (!task_sigpending(current)) + return false; if (unlikely(uprobe_deny_signal())) return false; -- 2.29.2