From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 898B21DE3BA for ; Fri, 13 Dec 2024 11:49:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734090544; cv=none; b=hGYavThYmY2duOdkYgeyugNmMFjhIBAgeE63J/B3X0kMVaqceM0ZESejw1CA3Ah5ik0VZP0kCIPOvKR7H2DW3XohtkEmGrFgojU+FJHOwH08taSuwneYBICkAWpz3s6tWmszaV/oTE0KhlXNlYnFHPUNVLzZcEHGkHMdxbnTrBo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734090544; c=relaxed/simple; bh=w6eEvjW0Y23K8Xyr2CrdpGAgALerym8PubNYNZVjT/4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZSy9vstLqnsuYJB84CgwCZiMFvVHHSXaejaYGvq2N60MNilDEgTdkaoXkXgAvwMm5X0F51PpdoFnySq8D7WOGD9ug2QTqahx52o25vJ0/S96jvBrKKf3tvngMx/86e0jEjbNz/jLExtSTKq0C//HiWTmA/VVf+e0OWtYR6w0dow= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=HXcUB8qQ; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HXcUB8qQ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1734090541; 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: in-reply-to:in-reply-to:references:references; bh=dv3t7bZUI3+tqYgjemQqhW+HuqlPgsCuhawdU9w0NMo=; b=HXcUB8qQK/1UVIDRsMnc8V6E7IjSw/1KtabYmEW+I6okWPeT4Hch6GOkoKX8DzLP7zF8qN KXWMm7eqMMk6EkuNfvQTPElaC35vxu6gKlXrGvyTO3VD+spJuGj2jlEN1fihChGOA+EpgB nGKa8RY+rRuP486K9KYfbIeclqgepuY= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-149-JM6VGjjpNjCfIaQUCLIzbA-1; Fri, 13 Dec 2024 06:48:58 -0500 X-MC-Unique: JM6VGjjpNjCfIaQUCLIzbA-1 X-Mimecast-MFC-AGG-ID: JM6VGjjpNjCfIaQUCLIzbA Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 202E2195604F; Fri, 13 Dec 2024 11:48:56 +0000 (UTC) Received: from fedora (unknown [10.72.116.91]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A7702300FA98; Fri, 13 Dec 2024 11:48:44 +0000 (UTC) Date: Fri, 13 Dec 2024 19:48:39 +0800 From: Ming Lei To: Thomas Gleixner Cc: David Woodhouse , Stefan Hajnoczi , Jason Wang , "x86@kernel.org" , hpa , dyoung , kexec , linux-ext4 , "Michael S. Tsirkin" , Stefano Garzarella , eperezma , Paolo Bonzini , Petr Mladek , John Ogness , Peter Zijlstra , Jens Axboe , "Rafael J. Wysocki" Subject: Re: Lockdep warnings on kexec (virtio_blk, hrtimers) Message-ID: References: <87ldwl9g93.ffs@tglx> <10f5d22150b548ec271e0a847ba2eb91139e6f61.camel@infradead.org> <87a5d0aibc.ffs@tglx> <874j38a16p.ffs@tglx> <9c4b189656a0a773227a11568171903989130bb7.camel@infradead.org> <871pybamoc.ffs@tglx> <87y10j95v7.ffs@tglx> Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87y10j95v7.ffs@tglx> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 On Fri, Dec 13, 2024 at 12:31:24PM +0100, Thomas Gleixner wrote: > On Fri, Dec 13 2024 at 19:09, Ming Lei wrote: > > On Fri, Dec 13, 2024 at 11:42:59AM +0100, Thomas Gleixner wrote: > >> That's the control thread on CPU0. The hotplug thread on CPU1 is stuck > >> here: > >> > >> task:cpuhp/1 state:D stack:0 pid:24 tgid:24 ppid:2 flags:0x00004000 > >> Call Trace: > >> > >> __schedule+0x51f/0x1a80 > >> schedule+0x3a/0x140 > >> schedule_timeout+0x90/0x110 > >> msleep+0x2b/0x40 > >> blk_mq_hctx_notify_offline+0x160/0x3a0 > >> cpuhp_invoke_callback+0x2a8/0x6c0 > >> cpuhp_thread_fun+0x1ed/0x270 > >> smpboot_thread_fn+0xda/0x1d0 > >> > >> So something with those blk_mq fixes went sideways. > > > > The cpuhp callback is just waiting for inflight IOs to be completed when > > the irq is still live. > > > > It looks same with the following report: > > > > https://lore.kernel.org/linux-scsi/F991D40F7D096653+20241203211857.0291ab1b@john-PC/ > > > > Still triggered in case of kexec & qemu, which should be one qemu > > problem. > > I'd rather say, that's a kexec problem. On the same instance a loop test > of suspend to ram with pm_test=core just works fine. That's equivalent > to the kexec scenario. It goes down to syscore_suspend() and skips the > actual suspend low level magic. It then resumes with syscore_resume() > and brings the machine back up. > > That runs for 2 hours now, while the kexec muck dies within 2 > minutes.... > > And if you look at the difference of these implementations, you might > notice that kexec just implemented some rudimentary version of the > actual suspend logic. Based on let's hope it works that way. > > This is just insane and should be rewritten to actually reuse the suspend > mechanism, which is way better tested than this kexec jump muck. But kexec is supposed to align with reboot/shutdown, instead of suspend, and it is calling ->shutdown() for notifying driver & device. Thanks, Ming