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 B673320F8F for ; Fri, 21 Jul 2023 19:21:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36B9FC433C7; Fri, 21 Jul 2023 19:21:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689967315; bh=wtOxTZ8UwHiWCbs/cEXo98uwcpGVQJFZLYmbTyHXHww=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X3cjbAa/eqe0Byevru/J7h09z1e+gLgiM5NQFHrDMsGkp3SGyUBIx00iibCj3JZqZ S0wLF+aigyso6eTV0Rm7F8GkYSnJBjW2XDrQ8boYx5iPMiDqhT0GaxklxChjVQZm25 ohNCIeq88ceFx9fwK7TTuC5q/sneIwU8t9xMvWRQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ross Lagerwall , Bjorn Helgaas Subject: [PATCH 6.1 120/223] PCI: Release resource invalidated by coalescing Date: Fri, 21 Jul 2023 18:06:13 +0200 Message-ID: <20230721160525.994452202@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230721160520.865493356@linuxfoundation.org> References: <20230721160520.865493356@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Ross Lagerwall commit e54223275ba1bc6f704a6bab015fcd2ae4f72572 upstream. When contiguous windows are coalesced by pci_register_host_bridge(), the second resource is expanded to include the first, and the first is invalidated and consequently not added to the bus. However, it remains in the resource hierarchy. For example, these windows: fec00000-fec7ffff : PCI Bus 0000:00 fec80000-fecbffff : PCI Bus 0000:00 are coalesced into this, where the first resource remains in the tree with start/end zeroed out: 00000000-00000000 : PCI Bus 0000:00 fec00000-fecbffff : PCI Bus 0000:00 In some cases (e.g. the Xen scratch region), this causes future calls to allocate_resource() to choose an inappropriate location which the caller cannot handle. Fix by releasing the zeroed-out resource and removing it from the resource hierarchy. [bhelgaas: commit log] Fixes: 7c3855c423b1 ("PCI: Coalesce host bridge contiguous apertures") Link: https://lore.kernel.org/r/20230525153248.712779-1-ross.lagerwall@citrix.com Signed-off-by: Ross Lagerwall Signed-off-by: Bjorn Helgaas Cc: stable@vger.kernel.org # v5.16+ Signed-off-by: Greg Kroah-Hartman --- drivers/pci/probe.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -994,8 +994,10 @@ static int pci_register_host_bridge(stru resource_list_for_each_entry_safe(window, n, &resources) { offset = window->offset; res = window->res; - if (!res->flags && !res->start && !res->end) + if (!res->flags && !res->start && !res->end) { + release_resource(res); continue; + } list_move_tail(&window->node, &bridge->windows);