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SubjectRe: [stable] [PATCH] Revert "ath9k: fix lockdep warning when unloading module" on stable kernels
On Mon, May 24, 2010 at 2:52 PM, Greg KH <greg@kroah.com> wrote:
> On Wed, May 19, 2010 at 05:33:49PM -0400, Luis R. Rodriguez wrote:
>> Johannes' patch 34e8950 titled:
>>
>>       mac80211: allow station add/remove to sleep
>>
>> changed the way mac80211 adds and removes peers. The new
>> sta_add() / sta_remove() callbacks allowed the driver callbacks
>> to sleep. Johannes also ported ath9k to use sta_add() / sta_remove()
>> via the patch 4ca7786 titled:
>>
>>       ath9k: convert to new station add/remove callbacks
>>
>> but this patch forgot to address a change in locking issue which
>> Ming Lei eventually found on his 2.6.33-wl #12 build. The 2.6.33-wl
>> build includes code for the 802.11 subsystem for 2.6.34 though so did
>> already have the above two patches (ath9k_sta_remove() on his trace),
>> the 2.6.33 kernel did not however have these two patches. Ming eventually
>> cured his lockdep warnign via the patch a9f042c titled:
>>
>>       ath9k: fix lockdep warning when unloading module
>>
>> This went in to 2.6.34 and although it was not marked as a stable
>> fix it did get trickled down and applied on both 2.6.33 and 2.6.32.
>>
>> In review, the culprits:
>>
>>       mac80211: allow station add/remove to sleep
>> git describe --contains 34e895075e21be3e21e71d6317440d1ee7969ad0
>> v2.6.34-rc1~233^2~49^2~107
>>
>>       ath9k: convert to new station add/remove callbacks
>> git describe --contains 4ca778605cfec53d8a689f0b57babb93b030c784
>> v2.6.34-rc1~233^2~49^2~10
>>
>>       ath9k: fix lockdep warning when unloading module
>>
>> This last one trickled down to 2.6.33 (OK), 2.6.33 (invalid) and 2.6.32 (invalid).
>>
>> git describe --contains a9f042cbe5284f34ccff15f3084477e11b39b17b
>> v2.6.34-rc2~48^2~77^2~7
>> git describe --contains 0524bcfa80f1fffb4e1fe18a0a28900869a58a7c
>> v2.6.33.2~125
>> git describe --contains 0dcc9985f34aef3c60bffab3dfc7f7ba3748f35a
>> v2.6.32.11~79
>>
>> The patch titled "ath9k: fix lockdep warning when unloading module"
>> should be reverted on both 2.6.33 and 2.6.32 as it is invalid and
>> actually ended up causing the following warning:
>>
>> ADDRCONF(NETDEV_CHANGE): wlan31: link becomes ready
>> phy0: WMM queue=2 aci=0 acm=0 aifs=3 cWmin=15 cWmax=1023 txop=0
>> phy0: WMM queue=3 aci=1 acm=0 aifs=7 cWmin=15 cWmax=1023 txop=0
>> phy0: WMM queue=1 aci=2 acm=0 aifs=2 cWmin=7 cWmax=15 txop=94
>> phy0: WMM queue=0 aci=3 acm=0 aifs=2 cWmin=3 cWmax=7 txop=47
>> phy0: device now idle
>> ------------[ cut here ]------------
>> WARNING: at kernel/softirq.c:143 local_bh_enable_ip+0x7b/0xa0()
>> Hardware name: 7660A14
>> Modules linked in: ath9k(-) mac80211 ath cfg80211 <whatever-bleh-etc>
>> Pid: 2003, comm: rmmod Not tainted 2.6.32.11 #6
>> Call Trace:
>>  [<ffffffff8105d178>] warn_slowpath_common+0x78/0xb0
>>  [<ffffffff8105d1bf>] warn_slowpath_null+0xf/0x20
>>  [<ffffffff81063f8b>] local_bh_enable_ip+0x7b/0xa0
>>  [<ffffffff815121e4>] _spin_unlock_bh+0x14/0x20
>>  [<ffffffffa034aea5>] ath_tx_node_cleanup+0x185/0x1b0 [ath9k]
>>  [<ffffffffa0345597>] ath9k_sta_notify+0x57/0xb0 [ath9k]
>>  [<ffffffffa02ac51a>] __sta_info_unlink+0x15a/0x260 [mac80211]
>>  [<ffffffffa02ac658>] sta_info_unlink+0x38/0x60 [mac80211]
>>  [<ffffffffa02b3fbe>] ieee80211_set_disassoc+0x1ae/0x210 [mac80211]
>>  [<ffffffffa02b42d9>] ieee80211_mgd_deauth+0x109/0x110 [mac80211]
>>  [<ffffffffa02ba409>] ieee80211_deauth+0x19/0x20 [mac80211]
>>  [<ffffffffa028160e>] __cfg80211_mlme_deauth+0xee/0x130 [cfg80211]
>>  [<ffffffff81118540>] ? init_object+0x50/0x90
>>  [<ffffffffa0285429>] __cfg80211_disconnect+0x159/0x1d0 [cfg80211]
>>  [<ffffffffa027125f>] cfg80211_netdev_notifier_call+0x10f/0x450 [cfg80211]
>>  [<ffffffff81514ca7>] notifier_call_chain+0x47/0x90
>>  [<ffffffff8107f501>] raw_notifier_call_chain+0x11/0x20
>>  [<ffffffff81442d66>] call_netdevice_notifiers+0x16/0x20
>>  [<ffffffff8144352d>] dev_close+0x4d/0xa0
>>  [<ffffffff814439a8>] rollback_registered+0x48/0x120
>>  [<ffffffff81443a9d>] unregister_netdevice+0x1d/0x70
>>  [<ffffffffa02b6cc4>] ieee80211_remove_interfaces+0x84/0xc0 [mac80211]
>>  [<ffffffffa02aa072>] ieee80211_unregister_hw+0x42/0xf0 [mac80211]
>>  [<ffffffffa0347bde>] ath_detach+0x8e/0x180 [ath9k]
>>  [<ffffffffa0347ce1>] ath_cleanup+0x11/0x50 [ath9k]
>>  [<ffffffffa0351a2c>] ath_pci_remove+0x1c/0x20 [ath9k]
>>  [<ffffffff8129d712>] pci_device_remove+0x32/0x60
>>  [<ffffffff81332373>] __device_release_driver+0x53/0xb0
>>  [<ffffffff81332498>] driver_detach+0xc8/0xd0
>>  [<ffffffff81331405>] bus_remove_driver+0x85/0xe0
>>  [<ffffffff81332a5a>] driver_unregister+0x5a/0x90
>>  [<ffffffff8129da00>] pci_unregister_driver+0x40/0xb0
>>  [<ffffffffa03518d0>] ath_pci_exit+0x10/0x20 [ath9k]
>>  [<ffffffffa0353cd5>] ath9k_exit+0x9/0x2a [ath9k]
>>  [<ffffffff81092838>] sys_delete_module+0x1a8/0x270
>>  [<ffffffff8107ebe9>] ? up_read+0x9/0x10
>>  [<ffffffff81011f82>] system_call_fastpath+0x16/0x1b
>> ---[ end trace fad957019ffdd40b ]---
>> phy0: Removed STA 00:22:6b:56:fd:e8
>> phy0: Destroyed STA 00:22:6b:56:fd:e8
>> wlan31: deauthenticating from 00:22:6b:56:fd:e8 by local choice (reason=3)
>> ath9k 0000:16:00.0: PCI INT A disabled
>>
>> The original lockdep fixed an issue where due to the new changes
>> the driver was not disabling the bottom halves but it is incorrect
>> to do this on the older kernels since IRQs are already disabled.
>>
>> Cc: Ming Lei <tom.leiming@gmail.com>
>> Cc: Johannes Berg <johannes@sipsolutions.net>
>> Cc: John W. Linville <linville@tuxdriver.com>
>
> For some reason, you never signed-off on this patch, why?  Care to send
> me a "Signed-off-by:" line so I can add it?

WTF, sorry, you're right, can you just peg it for me?

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>

Luis
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