From patchwork Fri May 12 21:07:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 13239782 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 25DD6C77B7C for ; Fri, 12 May 2023 21:10:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Date:MIME-Version:References:Subject:Cc :To:From:Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: List-Owner; bh=BtimLAOf5KlUPpqqi9TsUiu/WD0tUiEcTj20tR6rMJg=; b=X4vf4va7OT/XBs /i5xHGNwjGvKyW9kjYP762i/LR/vgfp5HASjtVdQA3/QheyyelXSFVAmTAMVx6nDAgeOnqKKCIFqu 2Imc2EAh65fA/IfY8KGjiFUnTOwQmil7MJjuWBqfD4zjQ5+mj1FGq9qo0Ida37MbJa5LfHOuKpMqB d3KKVDNTckWS6CVN8oOclh/q64CKcTeocjf435ZKi+C80hgzGDDwdJntlKJc8Md18ufYK/fh8RZ6J 1zLitVLiuvniM3La+81ctoSFsmLIBe6XXu4qyus8NVcTXvDRvdudCqgSyfK6HqUs57VvTqQlzTbpC bJRltntGMwKTeM76vTTQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pxa1w-00D1Vx-16; Fri, 12 May 2023 21:10:24 +0000 Received: from galois.linutronix.de ([193.142.43.55]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pxZzN-00Cyxg-17; Fri, 12 May 2023 21:07:47 +0000 Message-ID: <20230512205257.027075560@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1683925664; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=QdUmczWTVhK7K/GEDp21ZZBW6QiyoqITsSHkVbZTwSo=; b=QxFsCk8M0IwU/AWXJTbXBb8OmrmczN7eSVShQBD/xtp9CSloxhz1odBQguueWNc/vEM52/ 0Kl3gldkf4/0GgZgMmCaVqarwnt6c2WxoW5biu9zyuJifvGtM9/Jij2+5GahK4gODm1Y1Q 1hd8RJJvQbU0l+Gnh64z7qRhDPk39TNRP842ELWqPXiUeNBVOhZ36Jqvxt0WeLRCeD/TLr 8ppgeI8QfGvfUVwsNNPzx6acsMuK+QD0Sy+DuKWmGes0FQJYbkh9eWywGTaBGzAG8N39CJ IMTWuS0FUzsmcC8AS5xDPopwnYu51b4FiPLMJd67kDoqwu/y1krpwzf6eMhGgw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1683925664; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=QdUmczWTVhK7K/GEDp21ZZBW6QiyoqITsSHkVbZTwSo=; b=kpZz6QyptBqFfMzJcx1ZcoW9ytkNNQFs/6P8KAIUryIP/ZE4SXsEP30lmowL1TlGesMnkc +R008NAdqKJ6jZCQ== From: Thomas Gleixner To: LKML Cc: x86@kernel.org, David Woodhouse , Andrew Cooper , Brian Gerst , Arjan van de Veen , Paolo Bonzini , Paul McKenney , Tom Lendacky , Sean Christopherson , Oleksandr Natalenko , Paul Menzel , "Guilherme G. Piccoli" , Piotr Gorski , Usama Arif , Juergen Gross , Boris Ostrovsky , xen-devel@lists.xenproject.org, Russell King , Arnd Bergmann , linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Guo Ren , linux-csky@vger.kernel.org, Thomas Bogendoerfer , linux-mips@vger.kernel.org, "James E.J. Bottomley" , Helge Deller , linux-parisc@vger.kernel.org, Paul Walmsley , Palmer Dabbelt , linux-riscv@lists.infradead.org, Mark Rutland , Sabin Rapan , "Michael Kelley (LINUX)" , Ross Philipson , David Woodhouse Subject: [patch V4 29/37] cpu/hotplug: Reset task stack state in _cpu_up() References: <20230512203426.452963764@linutronix.de> MIME-Version: 1.0 Date: Fri, 12 May 2023 23:07:43 +0200 (CEST) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230512_140745_568031_F3214750 X-CRM114-Status: GOOD ( 16.77 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org From: David Woodhouse Commit dce1ca0525bf ("sched/scs: Reset task stack state in bringup_cpu()") ensured that the shadow call stack and KASAN poisoning were removed from a CPU's stack each time that CPU is brought up, not just once. This is not incorrect. However, with parallel bringup the idle thread setup will happen at a different step. As a consequence the cleanup in bringup_cpu() would be too late. Move the SCS/KASAN cleanup to the generic _cpu_up() function instead, which already ensures that the new CPU's stack is available, purely to allow for early failure. This occurs when the CPU to be brought up is in the CPUHP_OFFLINE state, which should correctly do the cleanup any time the CPU has been taken down to the point where such is needed. Signed-off-by: David Woodhouse Signed-off-by: Thomas Gleixner Tested-by: Mark Rutland Tested-by: Michael Kelley Reviewed-by: Mark Rutland --- kernel/cpu.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -771,12 +771,6 @@ static int bringup_cpu(unsigned int cpu) return -EAGAIN; /* - * Reset stale stack state from the last time this CPU was online. - */ - scs_task_reset(idle); - kasan_unpoison_task_stack(idle); - - /* * Some architectures have to walk the irq descriptors to * setup the vector space for the cpu which comes online. * @@ -1587,6 +1581,12 @@ static int _cpu_up(unsigned int cpu, int ret = PTR_ERR(idle); goto out; } + + /* + * Reset stale stack state from the last time this CPU was online. + */ + scs_task_reset(idle); + kasan_unpoison_task_stack(idle); } cpuhp_tasks_frozen = tasks_frozen;