I previously managed to reproduce a hang while scanning wireless
channels (reproducible with airodump-ng hopping channels); subsequent
lockdep instrumentation revealed a lock ordering issue [1].
Without knowing the design intent, it looks like the locks should be
taken in reverse order; please comment.
Signed-off-by: Daniel J Blueman <[email protected]>
--- [1]
=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.38-rc5-341cd #4
-------------------------------------------------------
airodump-ng/15445 is trying to acquire lock:
(&rdev->devlist_mtx){+.+.+.}, at: [<ffffffff816b1266>]
cfg80211_wext_siwfreq+0xc6/0x100
but task is already holding lock:
(&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>] cfg80211_wext_siwfreq+0xbc/0x100
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&wdev->mtx){+.+.+.}:
[<ffffffff810a79d6>] lock_acquire+0xc6/0x280
[<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0
[<ffffffff81696080>] cfg80211_netdev_notifier_call+0x430/0x5f0
[<ffffffff8109351b>] notifier_call_chain+0x8b/0x100
[<ffffffff810935b1>] raw_notifier_call_chain+0x11/0x20
[<ffffffff81576d92>] call_netdevice_notifiers+0x32/0x60
[<ffffffff815771a4>] __dev_notify_flags+0x34/0x80
[<ffffffff81577230>] dev_change_flags+0x40/0x70
[<ffffffff8158587c>] do_setlink+0x1fc/0x8d0
[<ffffffff81586042>] rtnl_setlink+0xf2/0x140
[<ffffffff81586923>] rtnetlink_rcv_msg+0x163/0x270
[<ffffffff8159d741>] netlink_rcv_skb+0xa1/0xd0
[<ffffffff815867b0>] rtnetlink_rcv+0x20/0x30
[<ffffffff8159d39a>] netlink_unicast+0x2ba/0x300
[<ffffffff8159dd57>] netlink_sendmsg+0x267/0x3e0
[<ffffffff8155e364>] sock_sendmsg+0xe4/0x110
[<ffffffff8155f3a3>] sys_sendmsg+0x253/0x3b0
[<ffffffff81003192>] system_call_fastpath+0x16/0x1b
-> #0 (&rdev->devlist_mtx){+.+.+.}:
[<ffffffff810a7222>] __lock_acquire+0x1622/0x1d10
[<ffffffff810a79d6>] lock_acquire+0xc6/0x280
[<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0
[<ffffffff816b1266>] cfg80211_wext_siwfreq+0xc6/0x100
[<ffffffff816b2fad>] ioctl_standard_call+0x5d/0xd0
[<ffffffff816b3223>] T.808+0x163/0x170
[<ffffffff816b326a>] wext_handle_ioctl+0x3a/0x90
[<ffffffff815798d2>] dev_ioctl+0x6f2/0x830
[<ffffffff8155cf3d>] sock_ioctl+0xfd/0x290
[<ffffffff8117dffd>] do_vfs_ioctl+0x9d/0x590
[<ffffffff8117e53a>] sys_ioctl+0x4a/0x80
[<ffffffff81003192>] system_call_fastpath+0x16/0x1b
other info that might help us debug this:
2 locks held by airodump-ng/15445:
#0: (rtnl_mutex){+.+.+.}, at: [<ffffffff81586782>] rtnl_lock+0x12/0x20
#1: (&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>]
cfg80211_wext_siwfreq+0xbc/0x100
stack backtrace:
Pid: 15445, comm: airodump-ng Not tainted 2.6.38-rc5-341cd #4
Call Trace:
[<ffffffff810a3f0a>] ? print_circular_bug+0xfa/0x100
[<ffffffff810a7222>] ? __lock_acquire+0x1622/0x1d10
[<ffffffff810a1f99>] ? trace_hardirqs_off_caller+0x29/0xc0
[<ffffffff810a79d6>] ? lock_acquire+0xc6/0x280
[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
[<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90
[<ffffffff816d6bce>] ? mutex_lock_nested+0x6e/0x4b0
[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
[<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90
[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
[<ffffffff816b2fad>] ? ioctl_standard_call+0x5d/0xd0
[<ffffffff8157818b>] ? __dev_get_by_name+0x9b/0xc0
[<ffffffff816b2f50>] ? ioctl_standard_call+0x0/0xd0
[<ffffffff816b3223>] ? T.808+0x163/0x170
[<ffffffff8112ddf2>] ? might_fault+0x72/0xd0
[<ffffffff816b326a>] ? wext_handle_ioctl+0x3a/0x90
[<ffffffff8112de3b>] ? might_fault+0xbb/0xd0
[<ffffffff815798d2>] ? dev_ioctl+0x6f2/0x830
[<ffffffff810a1bae>] ? put_lock_stats+0xe/0x40
[<ffffffff810a1c8c>] ? lock_release_holdtime+0xac/0x150
[<ffffffff8155cf3d>] ? sock_ioctl+0xfd/0x290
[<ffffffff8117dffd>] ? do_vfs_ioctl+0x9d/0x590
[<ffffffff8116c8ff>] ? fget_light+0x1df/0x3c0
[<ffffffff8117e53a>] ? sys_ioctl+0x4a/0x80
[<ffffffff81003192>] ? system_call_fastpath+0x16/0x1b
--- [2]
diff --git a/net/wireless/wext-compat.c b/net/wireless/wext-compat.c
index 3e5dbd4..d112f03 100644
--- a/net/wireless/wext-compat.c
+++ b/net/wireless/wext-compat.c
@@ -802,11 +802,11 @@ int cfg80211_wext_siwfreq(struct net_device *dev,
return freq;
if (freq == 0)
return -EINVAL;
- wdev_lock(wdev);
mutex_lock(&rdev->devlist_mtx);
+ wdev_lock(wdev);
err = cfg80211_set_freq(rdev, wdev, freq, NL80211_CHAN_NO_HT);
- mutex_unlock(&rdev->devlist_mtx);
wdev_unlock(wdev);
+ mutex_unlock(&rdev->devlist_mtx);
return err;
default:
return -EOPNOTSUPP;
--
Daniel J Blueman
On Tue, 2011-02-22 at 00:11 +0800, Daniel J Blueman wrote:
> I previously managed to reproduce a hang while scanning wireless
> channels (reproducible with airodump-ng hopping channels); subsequent
> lockdep instrumentation revealed a lock ordering issue [1].
>
> Without knowing the design intent, it looks like the locks should be
> taken in reverse order; please comment.
>
> Signed-off-by: Daniel J Blueman <[email protected]>
>
> --- [1]
Yeah, looks this way, thanks.
Acked-by: Johannes Berg <[email protected]>
> =======================================================
> [ INFO: possible circular locking dependency detected ]
> 2.6.38-rc5-341cd #4
> -------------------------------------------------------
> airodump-ng/15445 is trying to acquire lock:
> (&rdev->devlist_mtx){+.+.+.}, at: [<ffffffff816b1266>]
> cfg80211_wext_siwfreq+0xc6/0x100
>
> but task is already holding lock:
> (&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>] cfg80211_wext_siwfreq+0xbc/0x100
>
> which lock already depends on the new lock.
>
> the existing dependency chain (in reverse order) is:
>
> -> #1 (&wdev->mtx){+.+.+.}:
> [<ffffffff810a79d6>] lock_acquire+0xc6/0x280
> [<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0
> [<ffffffff81696080>] cfg80211_netdev_notifier_call+0x430/0x5f0
> [<ffffffff8109351b>] notifier_call_chain+0x8b/0x100
> [<ffffffff810935b1>] raw_notifier_call_chain+0x11/0x20
> [<ffffffff81576d92>] call_netdevice_notifiers+0x32/0x60
> [<ffffffff815771a4>] __dev_notify_flags+0x34/0x80
> [<ffffffff81577230>] dev_change_flags+0x40/0x70
> [<ffffffff8158587c>] do_setlink+0x1fc/0x8d0
> [<ffffffff81586042>] rtnl_setlink+0xf2/0x140
> [<ffffffff81586923>] rtnetlink_rcv_msg+0x163/0x270
> [<ffffffff8159d741>] netlink_rcv_skb+0xa1/0xd0
> [<ffffffff815867b0>] rtnetlink_rcv+0x20/0x30
> [<ffffffff8159d39a>] netlink_unicast+0x2ba/0x300
> [<ffffffff8159dd57>] netlink_sendmsg+0x267/0x3e0
> [<ffffffff8155e364>] sock_sendmsg+0xe4/0x110
> [<ffffffff8155f3a3>] sys_sendmsg+0x253/0x3b0
> [<ffffffff81003192>] system_call_fastpath+0x16/0x1b
>
> -> #0 (&rdev->devlist_mtx){+.+.+.}:
> [<ffffffff810a7222>] __lock_acquire+0x1622/0x1d10
> [<ffffffff810a79d6>] lock_acquire+0xc6/0x280
> [<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0
> [<ffffffff816b1266>] cfg80211_wext_siwfreq+0xc6/0x100
> [<ffffffff816b2fad>] ioctl_standard_call+0x5d/0xd0
> [<ffffffff816b3223>] T.808+0x163/0x170
> [<ffffffff816b326a>] wext_handle_ioctl+0x3a/0x90
> [<ffffffff815798d2>] dev_ioctl+0x6f2/0x830
> [<ffffffff8155cf3d>] sock_ioctl+0xfd/0x290
> [<ffffffff8117dffd>] do_vfs_ioctl+0x9d/0x590
> [<ffffffff8117e53a>] sys_ioctl+0x4a/0x80
> [<ffffffff81003192>] system_call_fastpath+0x16/0x1b
>
> other info that might help us debug this:
>
> 2 locks held by airodump-ng/15445:
> #0: (rtnl_mutex){+.+.+.}, at: [<ffffffff81586782>] rtnl_lock+0x12/0x20
> #1: (&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>]
> cfg80211_wext_siwfreq+0xbc/0x100
>
> stack backtrace:
> Pid: 15445, comm: airodump-ng Not tainted 2.6.38-rc5-341cd #4
> Call Trace:
> [<ffffffff810a3f0a>] ? print_circular_bug+0xfa/0x100
> [<ffffffff810a7222>] ? __lock_acquire+0x1622/0x1d10
> [<ffffffff810a1f99>] ? trace_hardirqs_off_caller+0x29/0xc0
> [<ffffffff810a79d6>] ? lock_acquire+0xc6/0x280
> [<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> [<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90
> [<ffffffff816d6bce>] ? mutex_lock_nested+0x6e/0x4b0
> [<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> [<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90
> [<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> [<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> [<ffffffff816b2fad>] ? ioctl_standard_call+0x5d/0xd0
> [<ffffffff8157818b>] ? __dev_get_by_name+0x9b/0xc0
> [<ffffffff816b2f50>] ? ioctl_standard_call+0x0/0xd0
> [<ffffffff816b3223>] ? T.808+0x163/0x170
> [<ffffffff8112ddf2>] ? might_fault+0x72/0xd0
> [<ffffffff816b326a>] ? wext_handle_ioctl+0x3a/0x90
> [<ffffffff8112de3b>] ? might_fault+0xbb/0xd0
> [<ffffffff815798d2>] ? dev_ioctl+0x6f2/0x830
> [<ffffffff810a1bae>] ? put_lock_stats+0xe/0x40
> [<ffffffff810a1c8c>] ? lock_release_holdtime+0xac/0x150
> [<ffffffff8155cf3d>] ? sock_ioctl+0xfd/0x290
> [<ffffffff8117dffd>] ? do_vfs_ioctl+0x9d/0x590
> [<ffffffff8116c8ff>] ? fget_light+0x1df/0x3c0
> [<ffffffff8117e53a>] ? sys_ioctl+0x4a/0x80
> [<ffffffff81003192>] ? system_call_fastpath+0x16/0x1b
>
> --- [2]
>
> diff --git a/net/wireless/wext-compat.c b/net/wireless/wext-compat.c
> index 3e5dbd4..d112f03 100644
> --- a/net/wireless/wext-compat.c
> +++ b/net/wireless/wext-compat.c
> @@ -802,11 +802,11 @@ int cfg80211_wext_siwfreq(struct net_device *dev,
> return freq;
> if (freq == 0)
> return -EINVAL;
> - wdev_lock(wdev);
> mutex_lock(&rdev->devlist_mtx);
> + wdev_lock(wdev);
> err = cfg80211_set_freq(rdev, wdev, freq, NL80211_CHAN_NO_HT);
> - mutex_unlock(&rdev->devlist_mtx);
> wdev_unlock(wdev);
> + mutex_unlock(&rdev->devlist_mtx);
> return err;
> default:
> return -EOPNOTSUPP;
On 22 February 2011 00:25, Johannes Berg <[email protected]> wrote:
> On Tue, 2011-02-22 at 00:11 +0800, Daniel J Blueman wrote:
>> I previously managed to reproduce a hang while scanning wireless
>> channels (reproducible with airodump-ng hopping channels); subsequent
>> lockdep instrumentation revealed a lock ordering issue [1].
>>
>> Without knowing the design intent, it looks like the locks should be
>> taken in reverse order; please comment.
>>
>> Signed-off-by: Daniel J Blueman <[email protected]>
>>
>> --- [1]
>
> Yeah, looks this way, thanks.
>
> Acked-by: Johannes Berg <[email protected]>
>
>> =======================================================
>> [ INFO: possible circular locking dependency detected ]
>> 2.6.38-rc5-341cd #4
>> -------------------------------------------------------
>> airodump-ng/15445 is trying to acquire lock:
>> ?(&rdev->devlist_mtx){+.+.+.}, at: [<ffffffff816b1266>]
>> cfg80211_wext_siwfreq+0xc6/0x100
>>
>> but task is already holding lock:
>> ?(&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>] cfg80211_wext_siwfreq+0xbc/0x100
>>
>> which lock already depends on the new lock.
>>
>> the existing dependency chain (in reverse order) is:
>>
>> -> #1 (&wdev->mtx){+.+.+.}:
>> ? ? ? ?[<ffffffff810a79d6>] lock_acquire+0xc6/0x280
>> ? ? ? ?[<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0
>> ? ? ? ?[<ffffffff81696080>] cfg80211_netdev_notifier_call+0x430/0x5f0
>> ? ? ? ?[<ffffffff8109351b>] notifier_call_chain+0x8b/0x100
>> ? ? ? ?[<ffffffff810935b1>] raw_notifier_call_chain+0x11/0x20
>> ? ? ? ?[<ffffffff81576d92>] call_netdevice_notifiers+0x32/0x60
>> ? ? ? ?[<ffffffff815771a4>] __dev_notify_flags+0x34/0x80
>> ? ? ? ?[<ffffffff81577230>] dev_change_flags+0x40/0x70
>> ? ? ? ?[<ffffffff8158587c>] do_setlink+0x1fc/0x8d0
>> ? ? ? ?[<ffffffff81586042>] rtnl_setlink+0xf2/0x140
>> ? ? ? ?[<ffffffff81586923>] rtnetlink_rcv_msg+0x163/0x270
>> ? ? ? ?[<ffffffff8159d741>] netlink_rcv_skb+0xa1/0xd0
>> ? ? ? ?[<ffffffff815867b0>] rtnetlink_rcv+0x20/0x30
>> ? ? ? ?[<ffffffff8159d39a>] netlink_unicast+0x2ba/0x300
>> ? ? ? ?[<ffffffff8159dd57>] netlink_sendmsg+0x267/0x3e0
>> ? ? ? ?[<ffffffff8155e364>] sock_sendmsg+0xe4/0x110
>> ? ? ? ?[<ffffffff8155f3a3>] sys_sendmsg+0x253/0x3b0
>> ? ? ? ?[<ffffffff81003192>] system_call_fastpath+0x16/0x1b
>>
>> -> #0 (&rdev->devlist_mtx){+.+.+.}:
>> ? ? ? ?[<ffffffff810a7222>] __lock_acquire+0x1622/0x1d10
>> ? ? ? ?[<ffffffff810a79d6>] lock_acquire+0xc6/0x280
>> ? ? ? ?[<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0
>> ? ? ? ?[<ffffffff816b1266>] cfg80211_wext_siwfreq+0xc6/0x100
>> ? ? ? ?[<ffffffff816b2fad>] ioctl_standard_call+0x5d/0xd0
>> ? ? ? ?[<ffffffff816b3223>] T.808+0x163/0x170
>> ? ? ? ?[<ffffffff816b326a>] wext_handle_ioctl+0x3a/0x90
>> ? ? ? ?[<ffffffff815798d2>] dev_ioctl+0x6f2/0x830
>> ? ? ? ?[<ffffffff8155cf3d>] sock_ioctl+0xfd/0x290
>> ? ? ? ?[<ffffffff8117dffd>] do_vfs_ioctl+0x9d/0x590
>> ? ? ? ?[<ffffffff8117e53a>] sys_ioctl+0x4a/0x80
>> ? ? ? ?[<ffffffff81003192>] system_call_fastpath+0x16/0x1b
>>
>> other info that might help us debug this:
>>
>> 2 locks held by airodump-ng/15445:
>> ?#0: ?(rtnl_mutex){+.+.+.}, at: [<ffffffff81586782>] rtnl_lock+0x12/0x20
>> ?#1: ?(&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>]
>> cfg80211_wext_siwfreq+0xbc/0x100
>>
>> stack backtrace:
>> Pid: 15445, comm: airodump-ng Not tainted 2.6.38-rc5-341cd #4
>> Call Trace:
>> ?[<ffffffff810a3f0a>] ? print_circular_bug+0xfa/0x100
>> ?[<ffffffff810a7222>] ? __lock_acquire+0x1622/0x1d10
>> ?[<ffffffff810a1f99>] ? trace_hardirqs_off_caller+0x29/0xc0
>> ?[<ffffffff810a79d6>] ? lock_acquire+0xc6/0x280
>> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
>> ?[<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90
>> ?[<ffffffff816d6bce>] ? mutex_lock_nested+0x6e/0x4b0
>> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
>> ?[<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90
>> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
>> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
>> ?[<ffffffff816b2fad>] ? ioctl_standard_call+0x5d/0xd0
>> ?[<ffffffff8157818b>] ? __dev_get_by_name+0x9b/0xc0
>> ?[<ffffffff816b2f50>] ? ioctl_standard_call+0x0/0xd0
>> ?[<ffffffff816b3223>] ? T.808+0x163/0x170
>> ?[<ffffffff8112ddf2>] ? might_fault+0x72/0xd0
>> ?[<ffffffff816b326a>] ? wext_handle_ioctl+0x3a/0x90
>> ?[<ffffffff8112de3b>] ? might_fault+0xbb/0xd0
>> ?[<ffffffff815798d2>] ? dev_ioctl+0x6f2/0x830
>> ?[<ffffffff810a1bae>] ? put_lock_stats+0xe/0x40
>> ?[<ffffffff810a1c8c>] ? lock_release_holdtime+0xac/0x150
>> ?[<ffffffff8155cf3d>] ? sock_ioctl+0xfd/0x290
>> ?[<ffffffff8117dffd>] ? do_vfs_ioctl+0x9d/0x590
>> ?[<ffffffff8116c8ff>] ? fget_light+0x1df/0x3c0
>> ?[<ffffffff8117e53a>] ? sys_ioctl+0x4a/0x80
>> ?[<ffffffff81003192>] ? system_call_fastpath+0x16/0x1b
>>
>> --- [2]
>>
>> diff --git a/net/wireless/wext-compat.c b/net/wireless/wext-compat.c
>> index 3e5dbd4..d112f03 100644
>> --- a/net/wireless/wext-compat.c
>> +++ b/net/wireless/wext-compat.c
>> @@ -802,11 +802,11 @@ int cfg80211_wext_siwfreq(struct net_device *dev,
>> ? ? ? ? ? ? ? ? ? ? ? return freq;
>> ? ? ? ? ? ? ? if (freq == 0)
>> ? ? ? ? ? ? ? ? ? ? ? return -EINVAL;
>> - ? ? ? ? ? ? wdev_lock(wdev);
>> ? ? ? ? ? ? ? mutex_lock(&rdev->devlist_mtx);
>> + ? ? ? ? ? ? wdev_lock(wdev);
>> ? ? ? ? ? ? ? err = cfg80211_set_freq(rdev, wdev, freq, NL80211_CHAN_NO_HT);
>> - ? ? ? ? ? ? mutex_unlock(&rdev->devlist_mtx);
>> ? ? ? ? ? ? ? wdev_unlock(wdev);
>> + ? ? ? ? ? ? mutex_unlock(&rdev->devlist_mtx);
>> ? ? ? ? ? ? ? return err;
>> ? ? ? default:
>> ? ? ? ? ? ? ? return -EOPNOTSUPP;
Please consider for -stable. This patch resolves the lock ordering
case my test exposed, and passes lockdep and extended testing.
Thanks,
Daniel
--
Daniel J Blueman
On Tue, Feb 22, 2011 at 09:15:47AM +0800, Daniel J Blueman wrote:
> On 22 February 2011 00:25, Johannes Berg <[email protected]> wrote:
> > On Tue, 2011-02-22 at 00:11 +0800, Daniel J Blueman wrote:
> >> I previously managed to reproduce a hang while scanning wireless
> >> channels (reproducible with airodump-ng hopping channels); subsequent
> >> lockdep instrumentation revealed a lock ordering issue [1].
> >>
> >> Without knowing the design intent, it looks like the locks should be
> >> taken in reverse order; please comment.
> >>
> >> Signed-off-by: Daniel J Blueman <[email protected]>
> >>
> >> --- [1]
> >
> > Yeah, looks this way, thanks.
> >
> > Acked-by: Johannes Berg <[email protected]>
> >
> >> =======================================================
> >> [ INFO: possible circular locking dependency detected ]
> >> 2.6.38-rc5-341cd #4
> >> -------------------------------------------------------
> >> airodump-ng/15445 is trying to acquire lock:
> >> ?(&rdev->devlist_mtx){+.+.+.}, at: [<ffffffff816b1266>]
> >> cfg80211_wext_siwfreq+0xc6/0x100
> >>
> >> but task is already holding lock:
> >> ?(&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>] cfg80211_wext_siwfreq+0xbc/0x100
> >>
> >> which lock already depends on the new lock.
> >>
> >> the existing dependency chain (in reverse order) is:
> >>
> >> -> #1 (&wdev->mtx){+.+.+.}:
> >> ? ? ? ?[<ffffffff810a79d6>] lock_acquire+0xc6/0x280
> >> ? ? ? ?[<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0
> >> ? ? ? ?[<ffffffff81696080>] cfg80211_netdev_notifier_call+0x430/0x5f0
> >> ? ? ? ?[<ffffffff8109351b>] notifier_call_chain+0x8b/0x100
> >> ? ? ? ?[<ffffffff810935b1>] raw_notifier_call_chain+0x11/0x20
> >> ? ? ? ?[<ffffffff81576d92>] call_netdevice_notifiers+0x32/0x60
> >> ? ? ? ?[<ffffffff815771a4>] __dev_notify_flags+0x34/0x80
> >> ? ? ? ?[<ffffffff81577230>] dev_change_flags+0x40/0x70
> >> ? ? ? ?[<ffffffff8158587c>] do_setlink+0x1fc/0x8d0
> >> ? ? ? ?[<ffffffff81586042>] rtnl_setlink+0xf2/0x140
> >> ? ? ? ?[<ffffffff81586923>] rtnetlink_rcv_msg+0x163/0x270
> >> ? ? ? ?[<ffffffff8159d741>] netlink_rcv_skb+0xa1/0xd0
> >> ? ? ? ?[<ffffffff815867b0>] rtnetlink_rcv+0x20/0x30
> >> ? ? ? ?[<ffffffff8159d39a>] netlink_unicast+0x2ba/0x300
> >> ? ? ? ?[<ffffffff8159dd57>] netlink_sendmsg+0x267/0x3e0
> >> ? ? ? ?[<ffffffff8155e364>] sock_sendmsg+0xe4/0x110
> >> ? ? ? ?[<ffffffff8155f3a3>] sys_sendmsg+0x253/0x3b0
> >> ? ? ? ?[<ffffffff81003192>] system_call_fastpath+0x16/0x1b
> >>
> >> -> #0 (&rdev->devlist_mtx){+.+.+.}:
> >> ? ? ? ?[<ffffffff810a7222>] __lock_acquire+0x1622/0x1d10
> >> ? ? ? ?[<ffffffff810a79d6>] lock_acquire+0xc6/0x280
> >> ? ? ? ?[<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0
> >> ? ? ? ?[<ffffffff816b1266>] cfg80211_wext_siwfreq+0xc6/0x100
> >> ? ? ? ?[<ffffffff816b2fad>] ioctl_standard_call+0x5d/0xd0
> >> ? ? ? ?[<ffffffff816b3223>] T.808+0x163/0x170
> >> ? ? ? ?[<ffffffff816b326a>] wext_handle_ioctl+0x3a/0x90
> >> ? ? ? ?[<ffffffff815798d2>] dev_ioctl+0x6f2/0x830
> >> ? ? ? ?[<ffffffff8155cf3d>] sock_ioctl+0xfd/0x290
> >> ? ? ? ?[<ffffffff8117dffd>] do_vfs_ioctl+0x9d/0x590
> >> ? ? ? ?[<ffffffff8117e53a>] sys_ioctl+0x4a/0x80
> >> ? ? ? ?[<ffffffff81003192>] system_call_fastpath+0x16/0x1b
> >>
> >> other info that might help us debug this:
> >>
> >> 2 locks held by airodump-ng/15445:
> >> ?#0: ?(rtnl_mutex){+.+.+.}, at: [<ffffffff81586782>] rtnl_lock+0x12/0x20
> >> ?#1: ?(&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>]
> >> cfg80211_wext_siwfreq+0xbc/0x100
> >>
> >> stack backtrace:
> >> Pid: 15445, comm: airodump-ng Not tainted 2.6.38-rc5-341cd #4
> >> Call Trace:
> >> ?[<ffffffff810a3f0a>] ? print_circular_bug+0xfa/0x100
> >> ?[<ffffffff810a7222>] ? __lock_acquire+0x1622/0x1d10
> >> ?[<ffffffff810a1f99>] ? trace_hardirqs_off_caller+0x29/0xc0
> >> ?[<ffffffff810a79d6>] ? lock_acquire+0xc6/0x280
> >> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> >> ?[<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90
> >> ?[<ffffffff816d6bce>] ? mutex_lock_nested+0x6e/0x4b0
> >> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> >> ?[<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90
> >> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> >> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> >> ?[<ffffffff816b2fad>] ? ioctl_standard_call+0x5d/0xd0
> >> ?[<ffffffff8157818b>] ? __dev_get_by_name+0x9b/0xc0
> >> ?[<ffffffff816b2f50>] ? ioctl_standard_call+0x0/0xd0
> >> ?[<ffffffff816b3223>] ? T.808+0x163/0x170
> >> ?[<ffffffff8112ddf2>] ? might_fault+0x72/0xd0
> >> ?[<ffffffff816b326a>] ? wext_handle_ioctl+0x3a/0x90
> >> ?[<ffffffff8112de3b>] ? might_fault+0xbb/0xd0
> >> ?[<ffffffff815798d2>] ? dev_ioctl+0x6f2/0x830
> >> ?[<ffffffff810a1bae>] ? put_lock_stats+0xe/0x40
> >> ?[<ffffffff810a1c8c>] ? lock_release_holdtime+0xac/0x150
> >> ?[<ffffffff8155cf3d>] ? sock_ioctl+0xfd/0x290
> >> ?[<ffffffff8117dffd>] ? do_vfs_ioctl+0x9d/0x590
> >> ?[<ffffffff8116c8ff>] ? fget_light+0x1df/0x3c0
> >> ?[<ffffffff8117e53a>] ? sys_ioctl+0x4a/0x80
> >> ?[<ffffffff81003192>] ? system_call_fastpath+0x16/0x1b
> >>
> >> --- [2]
> >>
> >> diff --git a/net/wireless/wext-compat.c b/net/wireless/wext-compat.c
> >> index 3e5dbd4..d112f03 100644
> >> --- a/net/wireless/wext-compat.c
> >> +++ b/net/wireless/wext-compat.c
> >> @@ -802,11 +802,11 @@ int cfg80211_wext_siwfreq(struct net_device *dev,
> >> ? ? ? ? ? ? ? ? ? ? ? return freq;
> >> ? ? ? ? ? ? ? if (freq == 0)
> >> ? ? ? ? ? ? ? ? ? ? ? return -EINVAL;
> >> - ? ? ? ? ? ? wdev_lock(wdev);
> >> ? ? ? ? ? ? ? mutex_lock(&rdev->devlist_mtx);
> >> + ? ? ? ? ? ? wdev_lock(wdev);
> >> ? ? ? ? ? ? ? err = cfg80211_set_freq(rdev, wdev, freq, NL80211_CHAN_NO_HT);
> >> - ? ? ? ? ? ? mutex_unlock(&rdev->devlist_mtx);
> >> ? ? ? ? ? ? ? wdev_unlock(wdev);
> >> + ? ? ? ? ? ? mutex_unlock(&rdev->devlist_mtx);
> >> ? ? ? ? ? ? ? return err;
> >> ? ? ? default:
> >> ? ? ? ? ? ? ? return -EOPNOTSUPP;
>
> Please consider for -stable. This patch resolves the lock ordering
> case my test exposed, and passes lockdep and extended testing.
Consider what? What is the git commit id of this patch in Linus's tree?
confused,
greg k-h
On Tue, Feb 22, 2011 at 12:02:22PM -0800, Greg KH wrote:
> On Tue, Feb 22, 2011 at 09:15:47AM +0800, Daniel J Blueman wrote:
> > On 22 February 2011 00:25, Johannes Berg <[email protected]> wrote:
> > > On Tue, 2011-02-22 at 00:11 +0800, Daniel J Blueman wrote:
> > >> I previously managed to reproduce a hang while scanning wireless
> > >> channels (reproducible with airodump-ng hopping channels); subsequent
> > >> lockdep instrumentation revealed a lock ordering issue [1].
> > >>
> > >> Without knowing the design intent, it looks like the locks should be
> > >> taken in reverse order; please comment.
> > >>
> > >> Signed-off-by: Daniel J Blueman <[email protected]>
> > >>
> > >> --- [1]
> > >
> > > Yeah, looks this way, thanks.
> > >
> > > Acked-by: Johannes Berg <[email protected]>
> > >
> > >> =======================================================
> > >> [ INFO: possible circular locking dependency detected ]
> > >> 2.6.38-rc5-341cd #4
> > >> -------------------------------------------------------
> > >> airodump-ng/15445 is trying to acquire lock:
> > >> ?(&rdev->devlist_mtx){+.+.+.}, at: [<ffffffff816b1266>]
> > >> cfg80211_wext_siwfreq+0xc6/0x100
> > >>
> > >> but task is already holding lock:
> > >> ?(&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>] cfg80211_wext_siwfreq+0xbc/0x100
> > >>
> > >> which lock already depends on the new lock.
> > >>
> > >> the existing dependency chain (in reverse order) is:
> > >>
> > >> -> #1 (&wdev->mtx){+.+.+.}:
> > >> ? ? ? ?[<ffffffff810a79d6>] lock_acquire+0xc6/0x280
> > >> ? ? ? ?[<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0
> > >> ? ? ? ?[<ffffffff81696080>] cfg80211_netdev_notifier_call+0x430/0x5f0
> > >> ? ? ? ?[<ffffffff8109351b>] notifier_call_chain+0x8b/0x100
> > >> ? ? ? ?[<ffffffff810935b1>] raw_notifier_call_chain+0x11/0x20
> > >> ? ? ? ?[<ffffffff81576d92>] call_netdevice_notifiers+0x32/0x60
> > >> ? ? ? ?[<ffffffff815771a4>] __dev_notify_flags+0x34/0x80
> > >> ? ? ? ?[<ffffffff81577230>] dev_change_flags+0x40/0x70
> > >> ? ? ? ?[<ffffffff8158587c>] do_setlink+0x1fc/0x8d0
> > >> ? ? ? ?[<ffffffff81586042>] rtnl_setlink+0xf2/0x140
> > >> ? ? ? ?[<ffffffff81586923>] rtnetlink_rcv_msg+0x163/0x270
> > >> ? ? ? ?[<ffffffff8159d741>] netlink_rcv_skb+0xa1/0xd0
> > >> ? ? ? ?[<ffffffff815867b0>] rtnetlink_rcv+0x20/0x30
> > >> ? ? ? ?[<ffffffff8159d39a>] netlink_unicast+0x2ba/0x300
> > >> ? ? ? ?[<ffffffff8159dd57>] netlink_sendmsg+0x267/0x3e0
> > >> ? ? ? ?[<ffffffff8155e364>] sock_sendmsg+0xe4/0x110
> > >> ? ? ? ?[<ffffffff8155f3a3>] sys_sendmsg+0x253/0x3b0
> > >> ? ? ? ?[<ffffffff81003192>] system_call_fastpath+0x16/0x1b
> > >>
> > >> -> #0 (&rdev->devlist_mtx){+.+.+.}:
> > >> ? ? ? ?[<ffffffff810a7222>] __lock_acquire+0x1622/0x1d10
> > >> ? ? ? ?[<ffffffff810a79d6>] lock_acquire+0xc6/0x280
> > >> ? ? ? ?[<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0
> > >> ? ? ? ?[<ffffffff816b1266>] cfg80211_wext_siwfreq+0xc6/0x100
> > >> ? ? ? ?[<ffffffff816b2fad>] ioctl_standard_call+0x5d/0xd0
> > >> ? ? ? ?[<ffffffff816b3223>] T.808+0x163/0x170
> > >> ? ? ? ?[<ffffffff816b326a>] wext_handle_ioctl+0x3a/0x90
> > >> ? ? ? ?[<ffffffff815798d2>] dev_ioctl+0x6f2/0x830
> > >> ? ? ? ?[<ffffffff8155cf3d>] sock_ioctl+0xfd/0x290
> > >> ? ? ? ?[<ffffffff8117dffd>] do_vfs_ioctl+0x9d/0x590
> > >> ? ? ? ?[<ffffffff8117e53a>] sys_ioctl+0x4a/0x80
> > >> ? ? ? ?[<ffffffff81003192>] system_call_fastpath+0x16/0x1b
> > >>
> > >> other info that might help us debug this:
> > >>
> > >> 2 locks held by airodump-ng/15445:
> > >> ?#0: ?(rtnl_mutex){+.+.+.}, at: [<ffffffff81586782>] rtnl_lock+0x12/0x20
> > >> ?#1: ?(&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>]
> > >> cfg80211_wext_siwfreq+0xbc/0x100
> > >>
> > >> stack backtrace:
> > >> Pid: 15445, comm: airodump-ng Not tainted 2.6.38-rc5-341cd #4
> > >> Call Trace:
> > >> ?[<ffffffff810a3f0a>] ? print_circular_bug+0xfa/0x100
> > >> ?[<ffffffff810a7222>] ? __lock_acquire+0x1622/0x1d10
> > >> ?[<ffffffff810a1f99>] ? trace_hardirqs_off_caller+0x29/0xc0
> > >> ?[<ffffffff810a79d6>] ? lock_acquire+0xc6/0x280
> > >> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> > >> ?[<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90
> > >> ?[<ffffffff816d6bce>] ? mutex_lock_nested+0x6e/0x4b0
> > >> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> > >> ?[<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90
> > >> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> > >> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> > >> ?[<ffffffff816b2fad>] ? ioctl_standard_call+0x5d/0xd0
> > >> ?[<ffffffff8157818b>] ? __dev_get_by_name+0x9b/0xc0
> > >> ?[<ffffffff816b2f50>] ? ioctl_standard_call+0x0/0xd0
> > >> ?[<ffffffff816b3223>] ? T.808+0x163/0x170
> > >> ?[<ffffffff8112ddf2>] ? might_fault+0x72/0xd0
> > >> ?[<ffffffff816b326a>] ? wext_handle_ioctl+0x3a/0x90
> > >> ?[<ffffffff8112de3b>] ? might_fault+0xbb/0xd0
> > >> ?[<ffffffff815798d2>] ? dev_ioctl+0x6f2/0x830
> > >> ?[<ffffffff810a1bae>] ? put_lock_stats+0xe/0x40
> > >> ?[<ffffffff810a1c8c>] ? lock_release_holdtime+0xac/0x150
> > >> ?[<ffffffff8155cf3d>] ? sock_ioctl+0xfd/0x290
> > >> ?[<ffffffff8117dffd>] ? do_vfs_ioctl+0x9d/0x590
> > >> ?[<ffffffff8116c8ff>] ? fget_light+0x1df/0x3c0
> > >> ?[<ffffffff8117e53a>] ? sys_ioctl+0x4a/0x80
> > >> ?[<ffffffff81003192>] ? system_call_fastpath+0x16/0x1b
> > >>
> > >> --- [2]
> > >>
> > >> diff --git a/net/wireless/wext-compat.c b/net/wireless/wext-compat.c
> > >> index 3e5dbd4..d112f03 100644
> > >> --- a/net/wireless/wext-compat.c
> > >> +++ b/net/wireless/wext-compat.c
> > >> @@ -802,11 +802,11 @@ int cfg80211_wext_siwfreq(struct net_device *dev,
> > >> ? ? ? ? ? ? ? ? ? ? ? return freq;
> > >> ? ? ? ? ? ? ? if (freq == 0)
> > >> ? ? ? ? ? ? ? ? ? ? ? return -EINVAL;
> > >> - ? ? ? ? ? ? wdev_lock(wdev);
> > >> ? ? ? ? ? ? ? mutex_lock(&rdev->devlist_mtx);
> > >> + ? ? ? ? ? ? wdev_lock(wdev);
> > >> ? ? ? ? ? ? ? err = cfg80211_set_freq(rdev, wdev, freq, NL80211_CHAN_NO_HT);
> > >> - ? ? ? ? ? ? mutex_unlock(&rdev->devlist_mtx);
> > >> ? ? ? ? ? ? ? wdev_unlock(wdev);
> > >> + ? ? ? ? ? ? mutex_unlock(&rdev->devlist_mtx);
> > >> ? ? ? ? ? ? ? return err;
> > >> ? ? ? default:
> > >> ? ? ? ? ? ? ? return -EOPNOTSUPP;
> >
> > Please consider for -stable. This patch resolves the lock ordering
> > case my test exposed, and passes lockdep and extended testing.
>
> Consider what? What is the git commit id of this patch in Linus's tree?
I just sent this to Dave M. The commit id should be
4f919a3bc54da01db829c520ce4b1fabfde1c3f7 when it hits Linus' tree.
Hth!
John
--
John W. Linville Someday the world will need a hero, and you
[email protected] might be all we have. Be ready.
On Tue, Feb 22, 2011 at 03:21:46PM -0500, John W. Linville wrote:
> On Tue, Feb 22, 2011 at 12:02:22PM -0800, Greg KH wrote:
> > On Tue, Feb 22, 2011 at 09:15:47AM +0800, Daniel J Blueman wrote:
> > > On 22 February 2011 00:25, Johannes Berg <[email protected]> wrote:
> > > > On Tue, 2011-02-22 at 00:11 +0800, Daniel J Blueman wrote:
> > > >> I previously managed to reproduce a hang while scanning wireless
> > > >> channels (reproducible with airodump-ng hopping channels); subsequent
> > > >> lockdep instrumentation revealed a lock ordering issue [1].
> > > >>
> > > >> Without knowing the design intent, it looks like the locks should be
> > > >> taken in reverse order; please comment.
> > > >>
> > > >> Signed-off-by: Daniel J Blueman <[email protected]>
> > > >>
> > > >> --- [1]
> > > >
> > > > Yeah, looks this way, thanks.
> > > >
> > > > Acked-by: Johannes Berg <[email protected]>
> > > >
> > > >> =======================================================
> > > >> [ INFO: possible circular locking dependency detected ]
> > > >> 2.6.38-rc5-341cd #4
> > > >> -------------------------------------------------------
> > > >> airodump-ng/15445 is trying to acquire lock:
> > > >> ?(&rdev->devlist_mtx){+.+.+.}, at: [<ffffffff816b1266>]
> > > >> cfg80211_wext_siwfreq+0xc6/0x100
> > > >>
> > > >> but task is already holding lock:
> > > >> ?(&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>] cfg80211_wext_siwfreq+0xbc/0x100
> > > >>
> > > >> which lock already depends on the new lock.
> > > >>
> > > >> the existing dependency chain (in reverse order) is:
> > > >>
> > > >> -> #1 (&wdev->mtx){+.+.+.}:
> > > >> ? ? ? ?[<ffffffff810a79d6>] lock_acquire+0xc6/0x280
> > > >> ? ? ? ?[<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0
> > > >> ? ? ? ?[<ffffffff81696080>] cfg80211_netdev_notifier_call+0x430/0x5f0
> > > >> ? ? ? ?[<ffffffff8109351b>] notifier_call_chain+0x8b/0x100
> > > >> ? ? ? ?[<ffffffff810935b1>] raw_notifier_call_chain+0x11/0x20
> > > >> ? ? ? ?[<ffffffff81576d92>] call_netdevice_notifiers+0x32/0x60
> > > >> ? ? ? ?[<ffffffff815771a4>] __dev_notify_flags+0x34/0x80
> > > >> ? ? ? ?[<ffffffff81577230>] dev_change_flags+0x40/0x70
> > > >> ? ? ? ?[<ffffffff8158587c>] do_setlink+0x1fc/0x8d0
> > > >> ? ? ? ?[<ffffffff81586042>] rtnl_setlink+0xf2/0x140
> > > >> ? ? ? ?[<ffffffff81586923>] rtnetlink_rcv_msg+0x163/0x270
> > > >> ? ? ? ?[<ffffffff8159d741>] netlink_rcv_skb+0xa1/0xd0
> > > >> ? ? ? ?[<ffffffff815867b0>] rtnetlink_rcv+0x20/0x30
> > > >> ? ? ? ?[<ffffffff8159d39a>] netlink_unicast+0x2ba/0x300
> > > >> ? ? ? ?[<ffffffff8159dd57>] netlink_sendmsg+0x267/0x3e0
> > > >> ? ? ? ?[<ffffffff8155e364>] sock_sendmsg+0xe4/0x110
> > > >> ? ? ? ?[<ffffffff8155f3a3>] sys_sendmsg+0x253/0x3b0
> > > >> ? ? ? ?[<ffffffff81003192>] system_call_fastpath+0x16/0x1b
> > > >>
> > > >> -> #0 (&rdev->devlist_mtx){+.+.+.}:
> > > >> ? ? ? ?[<ffffffff810a7222>] __lock_acquire+0x1622/0x1d10
> > > >> ? ? ? ?[<ffffffff810a79d6>] lock_acquire+0xc6/0x280
> > > >> ? ? ? ?[<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0
> > > >> ? ? ? ?[<ffffffff816b1266>] cfg80211_wext_siwfreq+0xc6/0x100
> > > >> ? ? ? ?[<ffffffff816b2fad>] ioctl_standard_call+0x5d/0xd0
> > > >> ? ? ? ?[<ffffffff816b3223>] T.808+0x163/0x170
> > > >> ? ? ? ?[<ffffffff816b326a>] wext_handle_ioctl+0x3a/0x90
> > > >> ? ? ? ?[<ffffffff815798d2>] dev_ioctl+0x6f2/0x830
> > > >> ? ? ? ?[<ffffffff8155cf3d>] sock_ioctl+0xfd/0x290
> > > >> ? ? ? ?[<ffffffff8117dffd>] do_vfs_ioctl+0x9d/0x590
> > > >> ? ? ? ?[<ffffffff8117e53a>] sys_ioctl+0x4a/0x80
> > > >> ? ? ? ?[<ffffffff81003192>] system_call_fastpath+0x16/0x1b
> > > >>
> > > >> other info that might help us debug this:
> > > >>
> > > >> 2 locks held by airodump-ng/15445:
> > > >> ?#0: ?(rtnl_mutex){+.+.+.}, at: [<ffffffff81586782>] rtnl_lock+0x12/0x20
> > > >> ?#1: ?(&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>]
> > > >> cfg80211_wext_siwfreq+0xbc/0x100
> > > >>
> > > >> stack backtrace:
> > > >> Pid: 15445, comm: airodump-ng Not tainted 2.6.38-rc5-341cd #4
> > > >> Call Trace:
> > > >> ?[<ffffffff810a3f0a>] ? print_circular_bug+0xfa/0x100
> > > >> ?[<ffffffff810a7222>] ? __lock_acquire+0x1622/0x1d10
> > > >> ?[<ffffffff810a1f99>] ? trace_hardirqs_off_caller+0x29/0xc0
> > > >> ?[<ffffffff810a79d6>] ? lock_acquire+0xc6/0x280
> > > >> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> > > >> ?[<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90
> > > >> ?[<ffffffff816d6bce>] ? mutex_lock_nested+0x6e/0x4b0
> > > >> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> > > >> ?[<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90
> > > >> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> > > >> ?[<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100
> > > >> ?[<ffffffff816b2fad>] ? ioctl_standard_call+0x5d/0xd0
> > > >> ?[<ffffffff8157818b>] ? __dev_get_by_name+0x9b/0xc0
> > > >> ?[<ffffffff816b2f50>] ? ioctl_standard_call+0x0/0xd0
> > > >> ?[<ffffffff816b3223>] ? T.808+0x163/0x170
> > > >> ?[<ffffffff8112ddf2>] ? might_fault+0x72/0xd0
> > > >> ?[<ffffffff816b326a>] ? wext_handle_ioctl+0x3a/0x90
> > > >> ?[<ffffffff8112de3b>] ? might_fault+0xbb/0xd0
> > > >> ?[<ffffffff815798d2>] ? dev_ioctl+0x6f2/0x830
> > > >> ?[<ffffffff810a1bae>] ? put_lock_stats+0xe/0x40
> > > >> ?[<ffffffff810a1c8c>] ? lock_release_holdtime+0xac/0x150
> > > >> ?[<ffffffff8155cf3d>] ? sock_ioctl+0xfd/0x290
> > > >> ?[<ffffffff8117dffd>] ? do_vfs_ioctl+0x9d/0x590
> > > >> ?[<ffffffff8116c8ff>] ? fget_light+0x1df/0x3c0
> > > >> ?[<ffffffff8117e53a>] ? sys_ioctl+0x4a/0x80
> > > >> ?[<ffffffff81003192>] ? system_call_fastpath+0x16/0x1b
> > > >>
> > > >> --- [2]
> > > >>
> > > >> diff --git a/net/wireless/wext-compat.c b/net/wireless/wext-compat.c
> > > >> index 3e5dbd4..d112f03 100644
> > > >> --- a/net/wireless/wext-compat.c
> > > >> +++ b/net/wireless/wext-compat.c
> > > >> @@ -802,11 +802,11 @@ int cfg80211_wext_siwfreq(struct net_device *dev,
> > > >> ? ? ? ? ? ? ? ? ? ? ? return freq;
> > > >> ? ? ? ? ? ? ? if (freq == 0)
> > > >> ? ? ? ? ? ? ? ? ? ? ? return -EINVAL;
> > > >> - ? ? ? ? ? ? wdev_lock(wdev);
> > > >> ? ? ? ? ? ? ? mutex_lock(&rdev->devlist_mtx);
> > > >> + ? ? ? ? ? ? wdev_lock(wdev);
> > > >> ? ? ? ? ? ? ? err = cfg80211_set_freq(rdev, wdev, freq, NL80211_CHAN_NO_HT);
> > > >> - ? ? ? ? ? ? mutex_unlock(&rdev->devlist_mtx);
> > > >> ? ? ? ? ? ? ? wdev_unlock(wdev);
> > > >> + ? ? ? ? ? ? mutex_unlock(&rdev->devlist_mtx);
> > > >> ? ? ? ? ? ? ? return err;
> > > >> ? ? ? default:
> > > >> ? ? ? ? ? ? ? return -EOPNOTSUPP;
> > >
> > > Please consider for -stable. This patch resolves the lock ordering
> > > case my test exposed, and passes lockdep and extended testing.
> >
> > Consider what? What is the git commit id of this patch in Linus's tree?
>
> I just sent this to Dave M. The commit id should be
> 4f919a3bc54da01db829c520ce4b1fabfde1c3f7 when it hits Linus' tree.
>
> Hth!
Yes it does, I'll look out for it.
thanks,
greg k-h