From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lukasz Jagiello , Stanislaw Gruszka , Emmanuel Grumbach , Johannes Berg Subject: [ 61/74] iwlwifi: dvm: fix calling ieee80211_chswitch_done() with NULL Date: Mon, 26 Aug 2013 18:08:59 -0700 Message-Id: <20130827010437.040427521@linuxfoundation.org> In-Reply-To: <20130827010424.535365435@linuxfoundation.org> References: <20130827010424.535365435@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.10-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 Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/iwlwifi/dvm/mac80211.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/drivers/net/wireless/iwlwifi/dvm/mac80211.c +++ b/drivers/net/wireless/iwlwifi/dvm/mac80211.c @@ -1059,7 +1059,10 @@ void iwl_chswitch_done(struct iwl_priv * 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); }