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 0255AC433F5 for ; Tue, 30 Nov 2021 23:08:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345138AbhK3XME (ORCPT ); Tue, 30 Nov 2021 18:12:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35358 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236634AbhK3XMB (ORCPT ); Tue, 30 Nov 2021 18:12:01 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 456D0C061746; Tue, 30 Nov 2021 15:08:41 -0800 (PST) Date: Tue, 30 Nov 2021 23:08:37 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1638313719; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BXCdHnS1zySe7YLcZSKygHbfQngvoJkIohTQI8Qi/tk=; b=lL0ELH/IK787czxd+9YQUshdF0KgtTaKpQ++cWMxRC/pIq4U7j6veEG3sHDiIKH5E7SS6N OFFep8pt1rq8wggXTxBAo1mUTHSMW3GxJtkBhRJg2m+uXLtKAjIxlvM6xJ+7jiyJ13EarW oW5aIo48xBRaq2DJrPQJakPW/o4BegRBzwSy+JhYh/BP3tYUwFT9Urkk8A0OMSBEzvDVq4 uhbKAl9SfZ+GrHm/nY+DWfWCCEGWQM4hg6MVguOhcVj5T1UU78J0S1refUwrutJ36zGNpy +KJu1mjd9MOQyEQ+/QbNpP9tLdP6qVR43/Vw9BsJZ4L6yTbddulS4bqHbNJaKg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1638313719; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BXCdHnS1zySe7YLcZSKygHbfQngvoJkIohTQI8Qi/tk=; b=qXDe20Uc8uyTkCzJ7MK3dbWQV7ojgjrAxongBDS+26htT+KqzFGY+axc0/7dHxowcc7wqh 9ieu3rn1YDWZbsCA== From: "tip-bot2 for Mark Rutland" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: core/entry] powerpc: Snapshot thread flags Cc: Mark Rutland , Thomas Gleixner , "Paul E. McKenney" , Benjamin Herrenschmidt , Michael Ellerman , Paul Mackerras , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20211129130653.2037928-11-mark.rutland@arm.com> References: <20211129130653.2037928-11-mark.rutland@arm.com> MIME-Version: 1.0 Message-ID: <163831371748.11128.4942543745019887361.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the core/entry branch of tip: Commit-ID: 985faa78687de6e583cfd8b8094d87dcb80c33a6 Gitweb: https://git.kernel.org/tip/985faa78687de6e583cfd8b8094d87dcb80c33a6 Author: Mark Rutland AuthorDate: Mon, 29 Nov 2021 13:06:52 Committer: Thomas Gleixner CommitterDate: Wed, 01 Dec 2021 00:06:44 +01:00 powerpc: Snapshot thread flags Some thread flags can be set remotely, and so even when IRQs are disabled, the flags can change under our feet. Generally this is unlikely to cause a problem in practice, but it is somewhat unsound, and KCSAN will legitimately warn that there is a data race. To avoid such issues, a snapshot of the flags has to be taken prior to using them. Some places already use READ_ONCE() for that, others do not. Convert them all to the new flag accessor helpers. Signed-off-by: Mark Rutland Signed-off-by: Thomas Gleixner Acked-by: Paul E. McKenney Cc: Benjamin Herrenschmidt Cc: Michael Ellerman Cc: Paul Mackerras Link: https://lore.kernel.org/r/20211129130653.2037928-11-mark.rutland@arm.com --- arch/powerpc/kernel/interrupt.c | 13 ++++++------- arch/powerpc/kernel/ptrace/ptrace.c | 3 +-- 2 files changed, 7 insertions(+), 9 deletions(-) diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c index df048e3..563ebfc 100644 --- a/arch/powerpc/kernel/interrupt.c +++ b/arch/powerpc/kernel/interrupt.c @@ -181,7 +181,7 @@ notrace long system_call_exception(long r3, long r4, long r5, local_irq_enable(); - if (unlikely(current_thread_info()->flags & _TIF_SYSCALL_DOTRACE)) { + if (unlikely(read_thread_flags() & _TIF_SYSCALL_DOTRACE)) { if (unlikely(trap_is_unsupported_scv(regs))) { /* Unsupported scv vector */ _exception(SIGILL, regs, ILL_ILLOPC, regs->nip); @@ -343,7 +343,7 @@ interrupt_exit_user_prepare_main(unsigned long ret, struct pt_regs *regs) unsigned long ti_flags; again: - ti_flags = READ_ONCE(current_thread_info()->flags); + ti_flags = read_thread_flags(); while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) { local_irq_enable(); if (ti_flags & _TIF_NEED_RESCHED) { @@ -359,7 +359,7 @@ again: do_notify_resume(regs, ti_flags); } local_irq_disable(); - ti_flags = READ_ONCE(current_thread_info()->flags); + ti_flags = read_thread_flags(); } if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && IS_ENABLED(CONFIG_PPC_FPU)) { @@ -437,7 +437,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3, /* Check whether the syscall is issued inside a restartable sequence */ rseq_syscall(regs); - ti_flags = current_thread_info()->flags; + ti_flags = read_thread_flags(); if (unlikely(r3 >= (unsigned long)-MAX_ERRNO) && is_not_scv) { if (likely(!(ti_flags & (_TIF_NOERROR | _TIF_RESTOREALL)))) { @@ -532,8 +532,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs) unsigned long flags; unsigned long ret = 0; unsigned long kuap; - bool stack_store = current_thread_info()->flags & - _TIF_EMULATE_STACK_STORE; + bool stack_store = read_thread_flags() & _TIF_EMULATE_STACK_STORE; if (regs_is_unrecoverable(regs)) unrecoverable_exception(regs); @@ -554,7 +553,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs) again: if (IS_ENABLED(CONFIG_PREEMPT)) { /* Return to preemptible kernel context */ - if (unlikely(current_thread_info()->flags & _TIF_NEED_RESCHED)) { + if (unlikely(read_thread_flags() & _TIF_NEED_RESCHED)) { if (preempt_count() == 0) preempt_schedule_irq(); } diff --git a/arch/powerpc/kernel/ptrace/ptrace.c b/arch/powerpc/kernel/ptrace/ptrace.c index 7c7093c..c43f77e 100644 --- a/arch/powerpc/kernel/ptrace/ptrace.c +++ b/arch/powerpc/kernel/ptrace/ptrace.c @@ -260,8 +260,7 @@ long do_syscall_trace_enter(struct pt_regs *regs) { u32 flags; - flags = READ_ONCE(current_thread_info()->flags) & - (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE); + flags = read_thread_flags() & (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE); if (flags) { int rc = tracehook_report_syscall_entry(regs);