From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758586Ab3IBJGL (ORCPT ); Mon, 2 Sep 2013 05:06:11 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:37786 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758458Ab3IBIz0 (ORCPT ); Mon, 2 Sep 2013 04:55:26 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Stanislaw Gruszka , Johannes Berg , Luis Henriques Subject: [PATCH 33/58] iwlwifi: dvm: fix calling ieee80211_chswitch_done() with NULL Date: Mon, 2 Sep 2013 09:54:18 +0100 Message-Id: <1378112083-9475-34-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1378112083-9475-1-git-send-email-luis.henriques@canonical.com> References: <1378112083-9475-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.5.7.21 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Stanislaw Gruszka commit 9186a1fd9ed190739423db84bc344d258ef3e3d7 upstream. If channel switch is pending and we remove interface we can crash like showed below due to passing NULL vif to mac80211: BUG: unable to handle kernel paging request at fffffffffffff8cc IP: [] strnlen+0xd/0x40 Call Trace: [] string.isra.3+0x3e/0xd0 [] vsnprintf+0x219/0x640 [] vscnprintf+0x11/0x30 [] vprintk_emit+0x115/0x4f0 [] printk+0x61/0x63 [] ieee80211_chswitch_done+0xaf/0xd0 [mac80211] [] iwl_chswitch_done+0x34/0x40 [iwldvm] [] iwlagn_commit_rxon+0x2a3/0xdc0 [iwldvm] [] ? iwlagn_set_rxon_chain+0x180/0x2c0 [iwldvm] [] iwl_set_mode+0x36/0x40 [iwldvm] [] iwlagn_mac_remove_interface+0x8d/0x1b0 [iwldvm] [] ieee80211_do_stop+0x29d/0x7f0 [mac80211] This is because we nulify ctx->vif in iwlagn_mac_remove_interface() before calling some other functions that teardown interface. To fix just check ctx->vif on iwl_chswitch_done(). We should not call ieee80211_chswitch_done() as channel switch works were already canceled by mac80211 in ieee80211_do_stop() -> ieee80211_mgd_stop(). Resolve: https://bugzilla.redhat.com/show_bug.cgi?id=979581 Reported-by: Lukasz Jagiello Signed-off-by: Stanislaw Gruszka Reviewed-by: Emmanuel Grumbach Signed-off-by: Johannes Berg [ luis: backported to 3.5: adjusted context ] Signed-off-by: Luis Henriques --- drivers/net/wireless/iwlwifi/iwl-mac80211.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/iwlwifi/iwl-mac80211.c b/drivers/net/wireless/iwlwifi/iwl-mac80211.c index 2c86c55..40bf6ad 100644 --- a/drivers/net/wireless/iwlwifi/iwl-mac80211.c +++ b/drivers/net/wireless/iwlwifi/iwl-mac80211.c @@ -958,7 +958,10 @@ void iwl_chswitch_done(struct iwl_priv *priv, bool is_success) if (test_bit(STATUS_EXIT_PENDING, &priv->status)) return; - if (test_and_clear_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status)) + if (!test_and_clear_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status)) + return; + + if (ctx->vif) ieee80211_chswitch_done(ctx->vif, is_success); } -- 1.8.3.2