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dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59900 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kWz12-00042z-4E for qemu-devel@archiver.kernel.org; Mon, 26 Oct 2020 05:42:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60190) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kWyzG-0002bb-KL for qemu-devel@nongnu.org; Mon, 26 Oct 2020 05:40:22 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:53146) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kWyzD-00054s-Ih for qemu-devel@nongnu.org; Mon, 26 Oct 2020 05:40:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1603705216; 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=oLmsJ99OS0U995klmvtVy0dW5YqlaC5YIIAYkHyV9pA=; b=Tfa4I9mkf4hzfDOz7p1wPm0ejdPmSK/X8a4660uvO/iRU0MyJOWhNQEXv46tbFHFz2mYH/ PJTw5Fu8vATyny1+d38ms//n9R7e+UYM6gLIFDImj8RQmpT3RM+NnV44xfScLZV3aR/vy1 q7DVb3xWOQKXZMw8KE2+ncml2D1OLvE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-48-EOTBlP2NNRKZ_HjKtXWNYA-1; Mon, 26 Oct 2020 05:40:14 -0400 X-MC-Unique: EOTBlP2NNRKZ_HjKtXWNYA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 072501009E30; Mon, 26 Oct 2020 09:40:13 +0000 (UTC) Received: from work-vm (ovpn-112-208.ams2.redhat.com [10.36.112.208]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F3FAD1043270; Mon, 26 Oct 2020 09:40:07 +0000 (UTC) Date: Mon, 26 Oct 2020 09:40:05 +0000 From: "Dr. David Alan Gilbert" To: Igor Mammedov Subject: Re: [PATCH] ACPI: Avoid infinite recursion when dump-vmstate Message-ID: <20201026094005.GC3277@work-vm> References: <20201019093156.2993284-1-liangpeng10@huawei.com> <20201023180933.2fe23875@redhat.com> <20201023185441.GP3038@work-vm> <20201023212346.79e54986@redhat.com> MIME-Version: 1.0 In-Reply-To: <20201023212346.79e54986@redhat.com> User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=63.128.21.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/25 21:03:19 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=-1, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peng Liang , mst@redhat.com, qemu-devel@nongnu.org, xiexiangyou@huawei.com, zhang.zhanghailiang@huawei.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Igor Mammedov (imammedo@redhat.com) wrote: > On Fri, 23 Oct 2020 19:54:41 +0100 > "Dr. David Alan Gilbert" wrote: > > > * Igor Mammedov (imammedo@redhat.com) wrote: > > > On Mon, 19 Oct 2020 17:31:56 +0800 > > > Peng Liang wrote: > > > > > > > There is a field with vmstate_ghes_state as vmsd in vmstate_ghes_state, > > > > which will lead to infinite recursion in dump_vmstate_vmsd. > > > > > > > > Fixes: a08a64627b ("ACPI: Record the Generic Error Status Block address") > > > > Reported-by: Euler Robot > > > > Signed-off-by: Peng Liang > > > > --- > > > > hw/acpi/generic_event_device.c | 3 +-- > > > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > > > > > diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c > > > > index 6df400e1ee16..4b6867300a55 100644 > > > > --- a/hw/acpi/generic_event_device.c > > > > +++ b/hw/acpi/generic_event_device.c > > > > @@ -334,8 +334,7 @@ static const VMStateDescription vmstate_ghes_state = { > > > > .minimum_version_id = 1, > > > > .needed = ghes_needed, > > > > .fields = (VMStateField[]) { > > > > - VMSTATE_STRUCT(ghes_state, AcpiGedState, 1, > > > > - vmstate_ghes_state, AcpiGhesState), > > > > + VMSTATE_UINT64(ghes_state.ghes_addr_le, AcpiGedState), > > > > > > not sure its' ok handle it this way, > > > > > > see how it is done with another structure: > > > > > > static const VMStateDescription vmstate_ged_state = { > > > .name = "acpi-ged-state", > > > .version_id = 1, > > > .minimum_version_id = 1, > > > .fields = (VMStateField[]) { > > > VMSTATE_UINT32(sel, GEDState), > > > VMSTATE_END_OF_LIST() > > > } > > > }; > > > > > > ... > > > > > > VMSTATE_STRUCT(ged_state, AcpiGedState, 1, vmstate_ged_state, GEDState), > > > > > > i.e. it looks like we are missing structure definition for AcpiGhesState > > > > > > CCing David, > > > to help with migration magic in case I'm wrong or missed something > > > > Yeh that's confusing :-) > > > > Given a: > > > > VMSTATE_STRUCT(a, B, 1, vmstate_c, C) > > > > We're saying there's a field 'a' in type B, and field 'a' > > should be of type C and be serialised using vmstate_c. > > > > That also means that in any vmstate_c, we're expecting it > > to be passed a type C generally. > > > > Having said that; you don't need a struct - you can get away > > with that VMSTATE_UINT64, there's two problems: > > > > a) That assumes that your ghes always stays that simple. > > b) If you wanted to store a Ghes from a number of different > > parent structures then you're stuck because your vmstate_ghes_state > > is bound to being a strict field of AcpiGedState. > > > > So yes, it's neatest to do it using a VMSD for AcpiGhesState > > > > And congratulations on finding a loop; I don't think we've ever had one > > before :-) > > can we make compilation fail in case VMSTATE_STRUCT is used but > is not actually provided like it was in this case? There's some type checking by the vmstate_offset_value macro; which I think would have verified that the 'ghes_state' field in AcpiGedState really is of type AcpiGhesState; but what we don't have is a type associated with a given VMStateDescription to know what type of state it's supposed to be called on. Dave > > > > Dave > > > > > > VMSTATE_END_OF_LIST() > > > > } > > > > }; > > > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK