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 C42081F941 for ; Fri, 21 Jul 2023 16:18:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 44E5BC433CA; Fri, 21 Jul 2023 16:18:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689956333; bh=iAoqKB9WFuX1v43fLLa5o//KLBmgW7TcxCgo7buNeb0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fmvJXrs2xeJ6mttuc7+mobvwej3PE+EkRfjf30NNFp5skqcHi15AfTWwPLA5EzHFN uEcHUpNtnAEyb9n48MR6suWjUnXCjIahRdnpsydJVMPML7taZjZEfJ/5xsiSgTKfJB NDqXp4etIZ96J6BrY7Og/4dvzWSzoJ9TeBeEYWDg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ross Lagerwall , Bjorn Helgaas Subject: [PATCH 6.4 170/292] PCI: Release resource invalidated by coalescing Date: Fri, 21 Jul 2023 18:04:39 +0200 Message-ID: <20230721160536.209433422@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230721160528.800311148@linuxfoundation.org> References: <20230721160528.800311148@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 @@ -997,8 +997,10 @@ 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);