From patchwork Tue Jan 24 15:41:09 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 9535437 X-Patchwork-Delegate: geert@linux-m68k.org Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A21576042D for ; Tue, 24 Jan 2017 15:41:13 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9551E280F4 for ; Tue, 24 Jan 2017 15:41:13 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8A2FE2817F; Tue, 24 Jan 2017 15:41:13 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EE539280F4 for ; Tue, 24 Jan 2017 15:41:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751150AbdAXPlM (ORCPT ); Tue, 24 Jan 2017 10:41:12 -0500 Received: from michel.telenet-ops.be ([195.130.137.88]:35240 "EHLO michel.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750795AbdAXPlL (ORCPT ); Tue, 24 Jan 2017 10:41:11 -0500 Received: from ayla.of.borg ([84.193.137.253]) by michel.telenet-ops.be with bizsmtp id cFh71u00K5UCtCs06Fh7C2; Tue, 24 Jan 2017 16:41:07 +0100 Received: from ramsan.of.borg ([192.168.97.29] helo=ramsan) by ayla.of.borg with esmtp (Exim 4.82) (envelope-from ) id 1cW3DX-0001mx-Br; Tue, 24 Jan 2017 16:41:07 +0100 Received: from geert by ramsan with local (Exim 4.82) (envelope-from ) id 1cW3Dc-0000v6-F6; Tue, 24 Jan 2017 16:41:12 +0100 From: Geert Uytterhoeven To: "David S. Miller" , Zach Brown , Volodymyr Bendiuga Cc: Andrew Lunn , =?UTF-8?q?Magnus=20=C3=96berg?= , Florian Fainelli , netdev@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH 1/2] net: phy: leds: Clear phy_num_led_triggers on failure to avoid crash Date: Tue, 24 Jan 2017 16:41:09 +0100 Message-Id: <1485272470-3497-2-git-send-email-geert+renesas@glider.be> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1485272470-3497-1-git-send-email-geert+renesas@glider.be> References: <1485272470-3497-1-git-send-email-geert+renesas@glider.be> Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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. --- 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);