From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D2E0D33B96A for ; Fri, 16 Jan 2026 17:34:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.32.30.218 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768584844; cv=none; b=PueV95Jx+hrWmdy11U2URJWPSq1fNMqS2yQDWY/CrAqcghpsOIki9H+xXquWeGEWzRc/l+LMbPtH+TH0uIyWBti37RInYjP3MIEh1PSXGZjOr8kFe7fYEV79qJwnT+XBxgwjOcFvtlmSXJQ0Tt4iXjgVK/8kLDy+TAOx8MGBLTg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768584844; c=relaxed/simple; bh=PGBEMNHsRdj5g/9VuDHy8yE6thd3mLpijspYB+g+6og=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VN5H8lpwEro7YMqnWTcJbeIMwkvLBFM8dbiXiheVUAl3t1mcItSpH+9ESM941OG94bnOgoJPg2RhG5DKSoGVN6+1kxvaxWIoK1NANm1+D+YOu2eXlu/S55wIPjJU9yL7mnZ5bLFpRF714gZzYkqF70x2lWuAqgmiAIkHh+8ybM4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk; spf=none smtp.mailfrom=armlinux.org.uk; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b=QFQLb4Dt; arc=none smtp.client-ip=78.32.30.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="QFQLb4Dt" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=XYA1/PW/0yIH+JE9voV2k0usAZeLlOr7n78hGG9p8IA=; b=QFQLb4DtnGGuGfg6tzYpMSXF/W ue4Jp5++XNHkR2KYLvgIRT7dbompth+qQ+kdEHlX3RYEmuv3XkPzJ19DPeN29oLEl10ve92Sb/rnj Y/GZhWvxaOGeNQW0YF8yBcKLMCEId2mlPlhi1ghGMfixcRWCdW/gWI5ZmuApKMF0fHhDtr+Z/QO6/ 7yI77qfOwnAu2iaboZeksr9zTCwGy4PUCuxB7yxvWwfl+NZN/Kphh8kF2poxmSjhe1lMbTrH4nJco gZv49PoDsMKt5V3MJ3h0ThE2gsd8pD6nzgE4IEXVC/2PR8uDwXxUsXiQTrx5vpRsW7v58TglFEb5g KAPt3GhA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:53306) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1vgnhn-000000002YA-3e5e; Fri, 16 Jan 2026 17:33:52 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.98.2) (envelope-from ) id 1vgnhk-000000003mL-3E2k; Fri, 16 Jan 2026 17:33:48 +0000 Date: Fri, 16 Jan 2026 17:33:48 +0000 From: "Russell King (Oracle)" To: Sebastian Andrzej Siewior Cc: linux-arm-kernel@lists.infradead.org, linux-rt-devel@lists.linux.dev, Arnd Bergmann , Linus Walleij , "Yadi.hu" , Bryan Brattlof Subject: Re: [PATCH v4 1/2] ARM: mm: fault: Enable interrupts before invoking __do_user_fault() Message-ID: References: <20260116170041.1059997-1-bigeasy@linutronix.de> <20260116170041.1059997-2-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: linux-rt-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260116170041.1059997-2-bigeasy@linutronix.de> Sender: Russell King (Oracle) On Fri, Jan 16, 2026 at 06:00:40PM +0100, Sebastian Andrzej Siewior wrote: > From: "Yadi.hu" > > A page fault from userland for a kernel address originates from from > do_sect_fault() (!LPAE) or do_page_fault() and ends in __do_user_fault() > by sending a signal. > > Sending a signal requires to acquire sighand_struct::siglock which is a > spinlock_t. On PREEMPT_RT spinlock_t becomes a sleeping spin lock which > requires interrupts to be enabled. Since the calling context is user > land, interrupts must have been enabled so it is fine to enable them in > this case. > > Enable interrupts in do_kernel_address_page_fault() unconditional in the > user_mode case(). > Enable interrupts in do_sect_fault() if they were previously enabled. Do you need any of this? __do_user_fault() now calls local_irq_enable() as almost the first thing it does. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!