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 A279626E164; Tue, 8 Apr 2025 12:31:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744115466; cv=none; b=b8LqjFsUDRc6p5BVnsvq8mMGEoA+3NNsAp/GmxWguBZa65MfJyfxRLwicla21qP/xeQeQO9+bix2ZzLoUPt9vvBgYlu2FGddoiLKcZImF8DINpCBSEMtwd7mAdbiKPsWWtY32mCni1FlgpZQcBUoJCAdqwHMNhzGn4AGtuiX/rQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744115466; c=relaxed/simple; bh=zv+PC9vVQarufBwsOho60QhAoD15vSwhc+T5YjwGt6Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=NkYnqpVCtYd6h5Qxq9eXUeicb5+pV5tv39C23ddeNHGptFBkB6z/8sWHl7TvNViCi05NhrnOPX5SxeSeQNWbYdSLCFB1bQiSVL751tpbh7ib1a7dthQxXoS6V4epFnpIpW4DKJvX4wn9PfJIs/I6KU8Etwx81GM6DobMAoXOjcI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=u0g4eWHs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="u0g4eWHs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 344A6C4CEE5; Tue, 8 Apr 2025 12:31:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744115466; bh=zv+PC9vVQarufBwsOho60QhAoD15vSwhc+T5YjwGt6Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u0g4eWHsqZ4ZvOXWHPCauSywFQPAUU1JVA3Q6bvcfeoFn+fluMwUsV4Y3JxqGdjBr 8RDCbBbei5lsgdTGcJkNkDDcF5AAuCqQIozJ/rwIw/1MorUzoyIMO0bA5CJqFJ91nX D0gXxdVq0VZRPYK6yvJjb8sQ/9ORd9dseKA0Pgz4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Wouter Bijlsma , Lukas Wunner , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= Subject: [PATCH 6.13 485/499] PCI/bwctrl: Fix NULL pointer dereference on bus number exhaustion Date: Tue, 8 Apr 2025 12:51:37 +0200 Message-ID: <20250408104903.453687612@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250408104851.256868745@linuxfoundation.org> References: <20250408104851.256868745@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lukas Wunner commit 667f053b05f00a007738cd7ed6fa1901de19dc7e upstream. When BIOS neglects to assign bus numbers to PCI bridges, the kernel attempts to correct that during PCI device enumeration. If it runs out of bus numbers, no pci_bus is allocated and the "subordinate" pointer in the bridge's pci_dev remains NULL. The PCIe bandwidth controller erroneously does not check for a NULL subordinate pointer and dereferences it on probe. Bandwidth control of unusable devices below the bridge is of questionable utility, so simply error out instead. This mirrors what PCIe hotplug does since commit 62e4492c3063 ("PCI: Prevent NULL dereference during pciehp probe"). The PCI core emits a message with KERN_INFO severity if it has run out of bus numbers. PCIe hotplug emits an additional message with KERN_ERR severity to inform the user that hotplug functionality is disabled at the bridge. A similar message for bandwidth control does not seem merited, given that its only purpose so far is to expose an up-to-date link speed in sysfs and throttle the link speed on certain laptops with limited Thermal Design Power. So error out silently. User-visible messages: pci 0000:16:02.0: bridge configuration invalid ([bus 00-00]), reconfiguring [...] pci_bus 0000:45: busn_res: [bus 45-74] end is updated to 74 pci 0000:16:02.0: devices behind bridge are unusable because [bus 45-74] cannot be assigned for them [...] pcieport 0000:16:02.0: pciehp: Hotplug bridge without secondary bus, ignoring [...] BUG: kernel NULL pointer dereference RIP: pcie_update_link_speed pcie_bwnotif_enable pcie_bwnotif_probe pcie_port_probe_service really_probe Fixes: 665745f27487 ("PCI/bwctrl: Re-add BW notification portdrv as PCIe BW controller") Reported-by: Wouter Bijlsma Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219906 Signed-off-by: Lukas Wunner Signed-off-by: Krzysztof Wilczyński Tested-by: Wouter Bijlsma Cc: stable@vger.kernel.org # v6.13+ Link: https://lore.kernel.org/r/3b6c8d973aedc48860640a9d75d20528336f1f3c.1742669372.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman --- drivers/pci/pcie/bwctrl.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/pci/pcie/bwctrl.c +++ b/drivers/pci/pcie/bwctrl.c @@ -294,6 +294,10 @@ static int pcie_bwnotif_probe(struct pci struct pci_dev *port = srv->port; int ret; + /* Can happen if we run out of bus numbers during enumeration. */ + if (!port->subordinate) + return -ENODEV; + struct pcie_bwctrl_data *data = devm_kzalloc(&srv->device, sizeof(*data), GFP_KERNEL); if (!data)