From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794590598; b=wE/E58fuDQp7Ol/puiVOvP6dwIQ2KyQQi7RajaEvaLz63SrxA2a5ozAfVuspLIklF/el 4OiSSpb72UC04PinLaWhEFSbUx5NJF3sUlX3v+Kc+ZImkq6Ukh9Cy+xP67rl1R9FsyQjI EhdDyJ6jwH8J0di7lA4fjCM4lAQv1HsCrfiE/K1UmVaMEjZ5Gz+e3LkO9xuL7fM/WJahc lW3pe1gGalx15EkcpZStDwjl5TecT8i4C7hHZV4CNyCKDsxz7Rq5vdzepcbXX/4kB7UIS 01wTarwA2svLWQ36c1Do9j2DP8sg4Nt3J9EJdmiCcmVivfE0gCTrLqqv4OEoggS3/KA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794590598; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=DDNl/h/1zqXpMXX8wEeTAz3UU3x3Ki1ydUhDwBi2quY=; b=oO3dw8YWX8WboizfK3O25w5ptqCCS+YNsnghH3nwjii/oI77dSm+wbJeGcZQoqSZB3hb yB/XN8HmJu242cpC01M4jBKO6MJ9fK8oaHW09vqmNCo9BUq+xN6BtBb5lmei7ouVWo2q3 E+ug0udXRYotJiRAJw4uGMYBeJEh4uqLS4e9HH1XBbVcjk9Kclc/q0Iyvl9l4H5jGNQ+V DoD3INa2vfk5c0YoBxHAIi6fNQpKjGU09exOji5OuK3582uaMQ9yznFq2i55VlgCocuvA XtyFHoV+282GTc5PkTaKkbKy2plZPpPs8JiQWNzr8KA9OGaDZ+9KqUkF5jZ/xp9i2cw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=EoYplgzU; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F396C606A330; Fri, 13 Nov 2026 17:23:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=EoYplgzU Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7D1D1F000C7; Fri, 13 Nov 2026 17:23:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794590597; bh=DDNl/h/1zqXpMXX8wEeTAz3UU3x3Ki1ydUhDwBi2quY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=EoYplgzUQ1/Cmk/7HCfkWKFQeoqyS1EuYsNyC7bWKBzixOod41ycrgDWe6ttuoNBJ BQaBuHy7D+jQZh6tavSRALirbwifD1iFGBf+MLwDyKZ2XTTtlhRlHotWpMUC+6KVfX t/uyl2ABhfl5lCZShdrF6P9bYd78LM8QIQb4g6pU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jonathan Cameron , Li Ming , "Gregory Price (Meta)" , Alison Schofield , Dave Jiang , Sasha Levin Subject: [PATCH 6.18 527/686] cxl/port: Clear cached dport pointers when a dport is removed Date: Fri, 13 Nov 2026 10:51:00 -0500 Message-ID: <20261113153838.985725605@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153820.902362109@linuxfoundation.org> References: <20261113153820.902362109@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dave Jiang [ Upstream commit 019560d23450a320f4060ff235563a5277ea8033 ] Switch decoders cache dport pointers in cxlsd->target[], and nothing clears them when a dport is freed. Readers then dereference freed memory. KASAN caught it under a cxl_test load/unload loop with concurrent sysfs reads (abbreviated). Clear the matching slots from cxl_dport_remove(), walking the port's decoders the way cxl_port_update_decoder_targets() does on the add side. Scan all nr_targets slots, the target[] allocation size, and clear every hit. Fixes: 8330671c57c7 ("cxl: Add helper to delete dport") Cc: stable@vger.kernel.org Assisted-by: LLM Reviewed-by: Jonathan Cameron Reviewed-by: Li Ming Reviewed-by: Gregory Price (Meta) Reviewed-by: Alison Schofield Link: https://patch.msgid.link/20261001154744.1095902-2-dave.jiang@intel.com Signed-off-by: Dave Jiang Signed-off-by: Sasha Levin --- drivers/cxl/core/port.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c index a7d3497f82c05..01655eeb43a8f 100644 --- a/drivers/cxl/core/port.c +++ b/drivers/cxl/core/port.c @@ -1105,11 +1105,40 @@ static void cond_cxl_root_unlock(struct cxl_port *port) device_unlock(&port->dev); } +static int clear_decoder_target(struct device *dev, void *data) +{ + struct cxl_dport *dport = data; + struct cxl_switch_decoder *cxlsd; + + if (!is_switch_decoder(dev)) + return 0; + + cxlsd = to_cxl_switch_decoder(dev); + guard(rwsem_write)(&cxl_rwsem.region); + + /* + * A dport can occupy more than one position of an interleave, so + * scan the whole target list rather than stopping at the first hit. + */ + for (int i = 0; i < cxlsd->nr_targets; i++) { + if (cxlsd->target[i] != dport) + continue; + cxlsd->target[i] = NULL; + dev_dbg(dev, "dport%d removed from target list, index %d\n", + dport->port_id, i); + } + + return 0; +} + static void cxl_dport_remove(void *data) { struct cxl_dport *dport = data; struct cxl_port *port = dport->port; + /* counterpart of cxl_port_update_decoder_targets() */ + device_for_each_child(&port->dev, dport, clear_decoder_target); + port->nr_dports--; xa_erase(&port->dports, (unsigned long) dport->dport_dev); put_device(dport->dport_dev); -- 2.53.0