From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 40245371068; Thu, 22 Jan 2026 18:47:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769107643; cv=none; b=uB9wIJ03Eo1+g3luR35JFqhUIW0A0aqc6CfU2d8k3jqeqswW4ssNtzFyPYbukPqbD32SQMXqgc+eE0pkkpAosH0JYDTtABT1aDPrrraUYc7KLRZUzGmwI9YF5DMB5IKkkkLZ2DdP3vI2DQtV56ZxAe/SSEG96o1rZMEQWhr+/1A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769107643; c=relaxed/simple; bh=puZkcLq0LJbBc92hUq9q08tH9W7ZSmix0U1xdnYs+V0=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=o10Al1qlEAH8J/9x8nuz6aizyc/+xMVdKazxbAoxjiyt45jZQOEC+4Tmr5vxpOzb53MPtCcPgYz1iWyftzp3F5DVIv2l1EN0sJgXxSiCmAvYceatGUo/prnhyV6OfoRD3OxLlsEBWMtc3E0rv/l+diTZcxbcecnws3B1dNFA+y0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Oopj1T3C; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Oopj1T3C" 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> 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 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