From patchwork Wed Jan 25 10:39:48 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 719626 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3v7hQm6QPJz9ssP for ; Wed, 25 Jan 2017 21:40:32 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752026AbdAYKkG (ORCPT ); Wed, 25 Jan 2017 05:40:06 -0500 Received: from andre.telenet-ops.be ([195.130.132.53]:58252 "EHLO andre.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751928AbdAYKjt (ORCPT ); Wed, 25 Jan 2017 05:39:49 -0500 Received: from ayla.of.borg ([84.193.137.253]) by andre.telenet-ops.be with bizsmtp id cafm1u00B5UCtCs01afmDU; Wed, 25 Jan 2017 11:39:46 +0100 Received: from ramsan.of.borg ([192.168.97.29] helo=ramsan) by ayla.of.borg with esmtp (Exim 4.82) (envelope-from ) id 1cWKzS-0004Gw-AO; Wed, 25 Jan 2017 11:39:46 +0100 Received: from geert by ramsan with local (Exim 4.82) (envelope-from ) id 1cWKzX-0002of-J2; Wed, 25 Jan 2017 11:39:51 +0100 From: Geert Uytterhoeven To: "David S. Miller" , Florian Fainelli , Zach Brown , Volodymyr Bendiuga Cc: Andrew Lunn , =?UTF-8?q?Magnus=20=C3=96berg?= , netdev@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v2 1/3] net: phy: leds: Clear phy_num_led_triggers on failure to avoid crash Date: Wed, 25 Jan 2017 11:39:48 +0100 Message-Id: <1485340790-10785-2-git-send-email-geert+renesas@glider.be> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1485340790-10785-1-git-send-email-geert+renesas@glider.be> References: <1485340790-10785-1-git-send-email-geert+renesas@glider.be> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org phy_attach_direct() ignores errors returned by phy_led_triggers_register(). I think that's OK, as LED triggers can be considered a non-critical feature. However, this causes problems later: - phy_led_trigger_change_speed() will access the array phy_device.phy_led_triggers, which has been freed in the error path of phy_led_triggers_register(), which may lead to a crash. - phy_led_triggers_unregister() will access the same array, leading to crashes during s2ram or poweroff, like: Unable to handle kernel NULL pointer dereference at virtual address 00000000 ... [] (__list_del_entry_valid) from [] (led_trigger_unregister+0x34/0xcc) [] (led_trigger_unregister) from [] (phy_led_triggers_unregister+0x28/0x34) [] (phy_led_triggers_unregister) from [] (phy_detach+0x30/0x74) [] (phy_detach) from [] (sh_eth_close+0x64/0x9c) [] (sh_eth_close) from [] (dpm_run_callback+0x48/0xc8) or: list_del corruption. prev->next should be dede6540, but was 2e323931 ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:52! ... [] (__list_del_entry_valid) from [] (led_trigger_unregister+0x34/0xcc) [] (led_trigger_unregister) from [] (phy_led_triggers_unregister+0x28/0x34) [] (phy_led_triggers_unregister) from [] (phy_detach+0x30/0x74) [] (phy_detach) from [] (sh_eth_close+0x6c/0xa4) [] (sh_eth_close) from [] (__dev_close_many+0xac/0xd0) To fix this, clear phy_device.phy_num_led_triggers in the error path of phy_led_triggers_register() fails. Note that the "No phy led trigger registered for speed" message will still be printed on link speed changes, which is a good cue that something went wrong with the LED triggers. Fixes: 2e0bc452f4721520 ("net: phy: leds: add support for led triggers on phy link state change") Signed-off-by: Geert Uytterhoeven Reviewed-by: Florian Fainelli --- Alternatively, phy_attach_direct() could consider phy_led_triggers_register() failures as fatal, so phy_led_trigger_change_speed() and phy_led_triggers_unregister() are never called afterwards. Exposed by commit 4567d686f5c6d955 ("phy: increase size of MII_BUS_ID_SIZE and bus_id"), which caused duplicate trigger names. v2: - Add Reviewed-by. --- drivers/net/phy/phy_led_triggers.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/phy/phy_led_triggers.c b/drivers/net/phy/phy_led_triggers.c index fa62bdf2f52694de..3f619e7371e97d8a 100644 --- a/drivers/net/phy/phy_led_triggers.c +++ b/drivers/net/phy/phy_led_triggers.c @@ -102,8 +102,10 @@ int phy_led_triggers_register(struct phy_device *phy) sizeof(struct phy_led_trigger) * phy->phy_num_led_triggers, GFP_KERNEL); - if (!phy->phy_led_triggers) - return -ENOMEM; + if (!phy->phy_led_triggers) { + err = -ENOMEM; + goto out_clear; + } for (i = 0; i < phy->phy_num_led_triggers; i++) { err = phy_led_trigger_register(phy, &phy->phy_led_triggers[i], @@ -120,6 +122,8 @@ int phy_led_triggers_register(struct phy_device *phy) while (i--) phy_led_trigger_unregister(&phy->phy_led_triggers[i]); devm_kfree(&phy->mdio.dev, phy->phy_led_triggers); +out_clear: + phy->phy_num_led_triggers = 0; return err; } EXPORT_SYMBOL_GPL(phy_led_triggers_register);