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 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 DA3C1D6CFA2 for ; Thu, 22 Jan 2026 18:47:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: Message-ID:Date:References:In-Reply-To:Subject:Cc:To:From:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=OByRIeYYG37nH3SEyJpXyw1KL+b7G9FbWCFF7m5McMg=; b=jFAB+hUffBs4tjs03MK3wY7EQC wHEgKFCv7xkq6R1QINfRho3h46olq5lWNCveHQjWAeILnoMSyXMDeNQW27l1RFIa051bmGdq8/3hI GImdflEM0xvY6B5sMhStnn/CrStlFQ5EEtBJ5nfOgUlDeeUPLwak4gDk6k2YWf9VxQGSGbH1D17XV sT2RkEaMIVGw7Rubhh3a4uHPksGM1KTCM92Uoi/a0sgIKIrOHEQn9JgYRJk/GpzfyuGXnNT/ZQYEx uhgese+DQA5YfvYJcS5wNELaJmD4rhv8T3vWiYuznias+ls7uWEGYiKTlA0UfYgaL8QWPmTXvwVZG dJpZGqZg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1viziH-00000007etG-1OZe; Thu, 22 Jan 2026 18:47:25 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1viziF-00000007esd-3MiF for linux-arm-kernel@lists.infradead.org; Thu, 22 Jan 2026 18:47:23 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id B441160053; Thu, 22 Jan 2026 18:47:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8AFC0C116C6; Thu, 22 Jan 2026 18:47:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769107642; bh=puZkcLq0LJbBc92hUq9q08tH9W7ZSmix0U1xdnYs+V0=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=Oopj1T3C87F1OYkkk/5BD0ca99ulodCm+Ezbv2lwzIfZcowo3h/CJJ0q0QidAVZoF Bf9+oZMr8wPnKv+D1oedhwr03xBH2o2ZfAbV2qNAdXA5GVXIKxX6QGx5wE4LVt6Abm 9vr0IIGCmDkRvRCBoNLmve3e5ezH+x9ECFZEyrzLEiTakr/4wVNOxgcwsHfk+iR9TG Pm1YBaMFd82xZvRFpRluuvy1Ecv1Gkw3QI9lf2rTFbtohxiMzfX3EGjR05bo/mbpDk HGa6HnzEkZ837z6ETr/vpqCLC3W9hg+eor5l2Dp3conaZmwspMkZNMpG+8A6SLAAmr IM2dAF1bynjRA== From: Thomas Gleixner To: Paolo Bonzini , Ankit Soni , Sean Christopherson , Marc Zyngier Cc: Oliver Upton , Joerg Roedel , David Woodhouse , Lu Baolu , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, Sairaj Kodilkar , Vasant Hegde , Maxim Levitsky , Joao Martins , Francesco Lavra , David Matlack , Naveen Rao , Crystal Wood Subject: Re: possible deadlock due to irq_set_thread_affinity() calling into the scheduler (was Re: [PATCH v3 38/62] KVM: SVM: Take and hold ir_list_lock across IRTE updates in IOMMU) In-Reply-To: <5bea843b-dec8-4f15-bb7c-1d0550542034@redhat.com> References: <20250611224604.313496-2-seanjc@google.com> <20250611224604.313496-40-seanjc@google.com> <42513cb3-3c2e-4aa8-b748-23b6656a5096@redhat.com> <874iovu742.ffs@tglx> <87pl7jsrdg.ffs@tglx> <5bea843b-dec8-4f15-bb7c-1d0550542034@redhat.com> Date: Thu, 22 Jan 2026 19:47:18 +0100 Message-ID: <87sebxtrgp.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jan 21 2026 at 19:13, Paolo Bonzini wrote: > On 1/8/26 22:53, Thomas Gleixner wrote: >> Are you still claiming that this is a kernel/irq bug? > > Not really, I did say I'd like to treat it as a kernel/irq bug... > but certainly didn't have hopes high enough to "claim" that. > I do think that it's ugly to have locks that are internal, > non-leaf and held around callbacks; but people smarter than > me have thought about it and you can't call it a bug anyway. Deep core code has a tendency to be ugly. But if it makes your life easier, then these wakeups can be delayed via an irq_work to be outside of the lock. That needs some life-time issues to be addressed, but should be doable. Thanks, tglx