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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 21D04C433F5 for ; Fri, 22 Oct 2021 13:57:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0403E60238 for ; Fri, 22 Oct 2021 13:57:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233071AbhJVN7h (ORCPT ); Fri, 22 Oct 2021 09:59:37 -0400 Received: from foss.arm.com ([217.140.110.172]:54470 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233054AbhJVN7a (ORCPT ); Fri, 22 Oct 2021 09:59:30 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5BA5514BF; Fri, 22 Oct 2021 06:57:13 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 480AB3F694; Fri, 22 Oct 2021 06:57:10 -0700 (PDT) From: Mark Rutland To: linux-kernel@vger.kernel.org Cc: benh@kernel.crashing.org, boqun.feng@gmail.com, bp@alien8.de, catalin.marinas@arm.com, dvyukov@google.com, elver@google.com, ink@jurassic.park.msu.ru, jonas@southpole.se, juri.lelli@redhat.com, linux@armlinux.org.uk, luto@kernel.org, mark.rutland@arm.com, mattst88@gmail.com, michal.simek@xilinx.com, mingo@redhat.com, mpe@ellerman.id.au, paulmck@kernel.org, paulus@samba.org, peterz@infradead.org, rth@twiddle.net, shorne@gmail.com, stefan.kristiansson@saunalahti.fi, tglx@linutronix.de, vincent.guittot@linaro.org, will@kernel.org Subject: [PATCH v6 05/10] arm: snapshot thread flags Date: Fri, 22 Oct 2021 14:56:38 +0100 Message-Id: <20211022135643.7442-6-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20211022135643.7442-1-mark.rutland@arm.com> References: <20211022135643.7442-1-mark.rutland@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Acked-by: Paul E. McKenney Cc: Russell King --- arch/arm/kernel/signal.c | 2 +- arch/arm/mm/alignment.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index a41e27ace391..c532a6041066 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -631,7 +631,7 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) } } local_irq_disable(); - thread_flags = current_thread_info()->flags; + thread_flags = read_thread_flags(); } while (thread_flags & _TIF_WORK_MASK); return 0; } diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c index ea81e89e7740..adbb3817d0be 100644 --- a/arch/arm/mm/alignment.c +++ b/arch/arm/mm/alignment.c @@ -990,7 +990,7 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs) * there is no work pending for this thread. */ raw_local_irq_disable(); - if (!(current_thread_info()->flags & _TIF_WORK_MASK)) + if (!(read_thread_flags() & _TIF_WORK_MASK)) set_cr(cr_no_alignment); } -- 2.11.0