lkml.org 
[lkml]   [2008]   [Jul]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: [crash] BUG: unable to handle kernel NULL pointer dereference at 0000000000000370
    I was looking at this out of interest, but I'm in no way familiar with the code.

    Looks to me that the error handling code in mac80211_hwsim is awkward. Which
    leads to it calling ieee80211_unregister_hw even when ieee80211_register_hw failed.

    The function has a for loop where it generates all simulated radios. when something
    fails, the error handling will call mac80211_hwsim_free which frees all simulated radios
    who's pointer isn't zero. However the information stored is insufficient to determine
    whether or not the call to ieee80211_register_hw succeeded or not for a specific radio.
    The included patch makes init_mac80211_hwsim clean up the current simulated radio,
    and then calls into mac80211_hwsim_free to clean up all the radios that did succeed.

    This however doesn't explain why the rate control registration failed.. build tested this,
    but had some problems reproducing the original problem.

    signed-off-by: Ian Schram <ischram@telenet.be>
    --- a/mac80211_hwsim.c 2008-07-21 18:48:38.000000000 +0200
    +++ b/mac80211_hwsim.c 2008-07-21 19:31:44.000000000 +0200
    @@ -364,8 +364,7 @@ static void mac80211_hwsim_free(void)
    struct mac80211_hwsim_data *data;
    data = hwsim_radios[i]->priv;
    ieee80211_unregister_hw(hwsim_radios[i]);
    - if (!IS_ERR(data->dev))
    - device_unregister(data->dev);
    + device_unregister(data->dev);
    ieee80211_free_hw(hwsim_radios[i]);
    }
    }
    @@ -437,7 +436,7 @@ static int __init init_mac80211_hwsim(vo
    "mac80211_hwsim: device_create_drvdata "
    "failed (%ld)\n", PTR_ERR(data->dev));
    err = -ENOMEM;
    - goto failed;
    + goto failed_drvdata;
    }
    data->dev->driver = &mac80211_hwsim_driver;

    @@ -461,7 +460,7 @@ static int __init init_mac80211_hwsim(vo
    if (err < 0) {
    printk(KERN_DEBUG "mac80211_hwsim: "
    "ieee80211_register_hw failed (%d)\n", err);
    - goto failed;
    + goto failed_hw;
    }

    printk(KERN_DEBUG "%s: hwaddr %s registered\n",
    @@ -479,9 +478,9 @@ static int __init init_mac80211_hwsim(vo
    rtnl_lock();

    err = dev_alloc_name(hwsim_mon, hwsim_mon->name);
    - if (err < 0) {
    + if (err < 0)
    goto failed_mon;
    - }
    +

    err = register_netdevice(hwsim_mon);
    if (err < 0)
    @@ -494,7 +493,14 @@ static int __init init_mac80211_hwsim(vo
    failed_mon:
    rtnl_unlock();
    free_netdev(hwsim_mon);
    + mac80211_hwsim_free();
    + return err;

    +failed_hw:
    + device_unregister(data->dev);
    +failed_drvdata:
    + ieee80211_free_hw(hw);
    + hwsim_radios[i] = 0;
    failed:
    mac80211_hwsim_free();
    return err;



    \
     
     \ /
      Last update: 2008-07-21 20:21    [W:0.025 / U:0.276 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site