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 E5AB0407CDB for ; Fri, 10 Jul 2026 09:57:57 +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=1783677480; cv=none; b=WhlnwKiCKVKMLtKMYbUwYTLd94Rw6rZh8JdYEe9nogRY7p4n66pa3DHO+9Mr/cw353APnyPCygnBxuaTgwQZtVLjtUCx98bDGWyvbVjM1O5UkSys9tIUZKTZtVAVT9S5yYMK0RRXO2ljBend6EGlhl7nICgE1VsBuA5Bfmnb3hs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783677480; c=relaxed/simple; bh=UDQ5iSt0yl+hIS2B9AYpnE8mlz1A06U4Mo8n6zMKKs0=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=hGyvqpz71tLqvvMjaTHVZdOQjEj8JILpzINFAubxfPH2lNv2rGErtqB5DGIXXF0rhMFF83pq3ptjSv6HX5PJvEUrZvzjUGa6+C4f1/suQOlOCOI5ty3pOHMVvmnHL8hbYmjU0Sbqxu3Ho+geUjuJzk8MptF0Zyt8WOOEf26kfLE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TGdSxBmC; 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="TGdSxBmC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 243BB1F00AC4; Fri, 10 Jul 2026 09:57:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783677476; bh=ghnk+dbD6A1tyBxAoJ0s58GH07hqyxQ8En0ljy8NSzs=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=TGdSxBmCa3CX6xvbAEFyBmy54ptb092aSrGXAj0uHBoTNg0nhY6ta2T08zktnYTjy RmwCy/53WzEom34Uzl6wWZnDMaiRiTOQrpzZamOPTxzbcut6EYwnzYUJRpo49K97yz MvbMiEbs4MlqFZhrVE3VCZ9EsTKOC1FxkQ/EHiQGYUsw74pOoP/nQiqau3WK8TbG6O a8YbSJuX4NwbYzQrMOKIj/rvDWY6d07c2ZSaGStju0F9xL+fbGqhhaUFyDcmmv57li 3bGqH1AAM4ddrbgCEcxvv+cRipBFYfEMlBOO2pl87lXttd3O7KEQSefABHBWi0FrVt G2gDSfddFwVRw== From: Pratyush Yadav To: David Matlack Cc: kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Andrew Morton , Mike Rapoport , Pasha Tatashin , Pratyush Yadav Subject: Re: [PATCH 0/2] liveupdate: Small FLB fixes In-Reply-To: (David Matlack's message of "Thu, 9 Jul 2026 13:51:40 -0700") References: <20260528174140.1921129-1-dmatlack@google.com> Date: Fri, 10 Jul 2026 11:57:53 +0200 Message-ID: <2vxzcxwvkvz2.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Thu, Jul 09 2026, David Matlack wrote: > On Thu, May 28, 2026 at 10:41=E2=80=AFAM David Matlack wrote: >> >> This series has 2 small fixes to how FLBs are managed. First is to >> increase the outgoing FLB refcount during liveupdate_flb_get_outgoing() >> so it cannot be freed while the caller is using it, and to align with >> the semantics of liveupdate_flb_get_incoming(). The second is to prevent >> FLB retrieve() from being called multiple times if the first attempt >> fails. >> >> Both of these changes are needed for the correctness of the PCI core >> support for Live Update: >> >> https://lore.kernel.org/linux-pci/20260522202410.3104264-1-dmatlack@go= ogle.com/ > > I'm wondering if we still want this series. After discussions with > Pratyush and Sami (some on-list, some off-list) the v7 of the PCI > series (which I haven't sent yet) does not depend on these changes for > correctness. > > Patch 1: PCI core no longer calls get_outgoing() outside the scope of > file handler callbacks. So there is no need to increment the reference > count. We could still keep this to make get_outgoing behave the same > way as get_incoming for consisteny at the cost of some extra > complexity to manage outgoing FLB refcoutn. I'm neutral on this one. I'll leave it up to Pasha's preference. > > Patch 2: PCI core panics if retrieve fails (proceeding without the PCI > FLB can lead to memory corruption due to ongoing DMA). So the behavior > of LUO on retrieve() errors does not matter. This patch is useful for sure. Sure, PCI might panic, but other FLB users like HugeTLB won't. And this patch fixes a real problem for those cases. The patch applies cleanly on liveupdate/next. So Mike, would you mind applying patch 2/2 now? We can wait for Pasha to chime in for 1/2. > > Should we drop this series? --=20 Regards, Pratyush Yadav