• Stanislaw Gruszka's avatar
    iwlwifi: dvm: fix calling ieee80211_chswitch_done() with NULL · 9186a1fd
    Stanislaw Gruszka authored
    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: [<ffffffff8130924d>] strnlen+0xd/0x40
    Call Trace:
     [<ffffffff8130ad2e>] string.isra.3+0x3e/0xd0
     [<ffffffff8130bf99>] vsnprintf+0x219/0x640
     [<ffffffff8130c481>] vscnprintf+0x11/0x30
     [<ffffffff81061585>] vprintk_emit+0x115/0x4f0
     [<ffffffff81657bd5>] printk+0x61/0x63
     [<ffffffffa048987f>] ieee80211_chswitch_done+0xaf/0xd0 [mac80211]
     [<ffffffffa04e7b34>] iwl_chswitch_done+0x34/0x40 [iwldvm]
     [<ffffffffa04f83c3>] iwlagn_commit_rxon+0x2a3/0xdc0 [iwldvm]
     [<ffffffffa04ebc50>] ? iwlagn_set_rxon_chain+0x180/0x2c0 [iwldvm]
     [<ffffffffa04e5e76>] iwl_set_mode+0x36/0x40 [iwldvm]
     [<ffffffffa04e5f0d>] iwlagn_mac_remove_interface+0x8d/0x1b0 [iwldvm]
     [<ffffffffa0459b3d>] 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
    
    Cc: stable@vger.kernel.org
    Reported-by: default avatarLukasz Jagiello <jagiello.lukasz@gmail.com>
    Signed-off-by: default avatarStanislaw Gruszka <sgruszka@redhat.com>
    Reviewed-by: default avatarEmmanuel Grumbach <emmanuel.grumbach@intel.com>
    Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
    9186a1fd
mac80211.c 46.2 KB