From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C07A84825BD for ; Thu, 15 Oct 2026 07:46:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792050406; cv=none; b=cZ0m39e/3ACkAOkJCj/HoIeNAPtGbAs3EQlgaQdBgyv65dyPhQndUjlWEPFXImPgya9o2MYjykMXU5QsBJoYi71T1f5JTgabfQQbgHmJfEZzy1tAPaKCYnLl3nKp64U+BlO5++AK4DhivGS7YUEPV5q/QOVfevRnbTDzf8VLWlc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792050406; c=relaxed/simple; bh=vo02vviHqOw8hAzQ2cOcJfgBOWMLopBDsr2aaLSvZbM=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=gGloaes2EZzE0YnRF9M7kjLILNMGBVyS4jXobFBjFP5eM1bV4kn4HpyVmddLZZ2FDkjVc4qJ1NiG+UVJwDnUu/wsFYEHG+nWh21GPDeAwhmHTbXhOmtpJCpzrJoOmBohRp/tZph7SBVPjD1zB8B2upuz9plH9UjnaSwfkf1HrPM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Igh2BNYd; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Igh2BNYd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5C4251F000C4; Thu, 15 Oct 2026 07:46:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792050402; bh=cUZThg+HVXlgUHBB9RuoLPOfEs+nTSITP52lqWy14gY=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=Igh2BNYd+PHupSVza0UYmMtLZ8gvj4hD26NOXgDGWtdAdh2219NOKg6gkhNCtWQr6 +PWUa97wq1lUl+RTWzpLrJmqvfKenGaUTo4zVfKCyrn3TjBvHAnKZh675Hnu0u0TKd 6Y8M8ONMQ/XfqtVn3fqYzYfb7ikQZLvyHNqmGVlPu4nE+l1/pzm2Sd133Z/V+IClR2 PME9/1OqpkbR8NADCwrzEZE0z8nV7amgyq9dsvw3bl8+88FYj/zmYd6hwgGoXFf+Hk QC4C5it/Rnf/zH5sMLoGYlgcsNaO9XIIrBZjgLi1R4BapgvjKOjepNkRUVt1e+Nf2R mFUMz1zqWILfw== From: Thomas Gleixner To: Igor Velkov via B4 Relay Cc: Radu Rendec , Marc Zyngier , Eliav Farber , Catalin Marinas , Will Deacon , Mark Rutland , Baoquan He , Heiko Stuebner , kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org, Igor Velkov Subject: Re: [PATCH RFC] genirq/kexec: Do not take the bus lock of an interrupt chip on the crash path In-Reply-To: <20261005-kexec-irq-bus-lock-v1-1-09f6b5323460@iav.lv> References: <20261005-kexec-irq-bus-lock-v1-1-09f6b5323460@iav.lv> Date: Thu, 15 Oct 2026 09:46:38 +0200 Message-ID: <87zewfe78h.ffs@fw13> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Mon, Oct 05 2026 at 01:22, Igor Velkov via B4 Relay wrote: > diff --git a/kernel/irq/kexec.c b/kernel/irq/kexec.c > index 1a3deffe6b5b..c6c745cc76a2 100644 > --- a/kernel/irq/kexec.c > +++ b/kernel/irq/kexec.c > @@ -20,7 +20,11 @@ void machine_kexec_mask_interrupts(void) > if (!chip || !irqd_is_started(&desc->irq_data)) > continue; > > - if (IS_ENABLED(CONFIG_GENERIC_IRQ_KEXEC_CLEAR_VM_FORWARD)) { > + /* > + * irq_set_irqchip_state() takes the bus lock, and a chip that > + * has one may sleep or talk to its bus when the lock is dropped. > + */ > + if (IS_ENABLED(CONFIG_GENERIC_IRQ_KEXEC_CLEAR_VM_FORWARD) && !chip->irq_bus_lock) { > /* > * First try to remove the active state from an interrupt which is forwarded > * to a VM. If the interrupt is not forwarded, try to EOI the interrupt. That's error prone in case that the outermost domain implements irq_bus_lock() and the parent domain has a set_state() callback. machine_kexec_mask_interrupts() does not take locks in general for the obvious reasons, so instead of playing this conditional irq_bus_lock game, this simply can avoid taking the lock. Something like the uncompiled below. Thanks, tglx --- diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 57eff26fa646..bdb47837c66f 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -2735,6 +2735,28 @@ int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which, bool * } EXPORT_SYMBOL_GPL(irq_get_irqchip_state); +int __irq_set_irqchip_state(struct irq_desc *desc, enum irqchip_irq_state which, bool val) +{ + struct irq_data *data = irq_desc_get_irq_data(desc); + struct irq_chip *chip; + + do { + chip = irq_data_get_irq_chip(data); + + if (WARN_ON_ONCE(!chip)) + return -ENODEV; + + if (chip->irq_set_irqchip_state) + break; + + data = irqd_get_parent_data(data); + } while (data); + + if (data) + return chip->irq_set_irqchip_state(data, which, val); + return -EINVAL; +} + /** * irq_set_irqchip_state - set the state of a forwarded interrupt. * @irq: Interrupt line that is forwarded to a VM @@ -2749,25 +2771,8 @@ EXPORT_SYMBOL_GPL(irq_get_irqchip_state); */ int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which, bool val) { - scoped_irqdesc_get_and_buslock(irq, 0) { - struct irq_data *data = irq_desc_get_irq_data(scoped_irqdesc); - struct irq_chip *chip; - - do { - chip = irq_data_get_irq_chip(data); - - if (WARN_ON_ONCE(!chip)) - return -ENODEV; - - if (chip->irq_set_irqchip_state) - break; - - data = irqd_get_parent_data(data); - } while (data); - - if (data) - return chip->irq_set_irqchip_state(data, which, val); - } + scoped_irqdesc_get_and_buslock(irq, 0) + return __irq_set_irqchip_state(scoped_irqdesc, which, val); return -EINVAL; } EXPORT_SYMBOL_GPL(irq_set_irqchip_state);