linux/drivers/net/wireless/rt2x00
Stanislaw Gruszka e5851dac2c rt2x00: use atomic variable for seqno
Remove spinlock as atomic_t can be used instead. Note we use only 16
lower bits, upper bits are changed but we impilcilty cast to u16.

This fix possible deadlock on IBSS mode reproted by lockdep:

=================================
[ INFO: inconsistent lock state ]
3.4.0-wl+ #4 Not tainted
---------------------------------
inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
kworker/u:2/30374 [HC0[0]:SC0[0]:HE1:SE1] takes:
 (&(&intf->seqlock)->rlock){+.?...}, at: [<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
{IN-SOFTIRQ-W} state was registered at:
  [<c04978ab>] __lock_acquire+0x47b/0x1050
  [<c0498504>] lock_acquire+0x84/0xf0
  [<c0835733>] _raw_spin_lock+0x33/0x40
  [<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
  [<f9979f2a>] rt2x00queue_write_tx_frame+0x1a/0x300 [rt2x00lib]
  [<f997834f>] rt2x00mac_tx+0x7f/0x380 [rt2x00lib]
  [<f98fe363>] __ieee80211_tx+0x1b3/0x300 [mac80211]
  [<f98ffdf5>] ieee80211_tx+0x105/0x130 [mac80211]
  [<f99000dd>] ieee80211_xmit+0xad/0x100 [mac80211]
  [<f9900519>] ieee80211_subif_start_xmit+0x2d9/0x930 [mac80211]
  [<c0782e87>] dev_hard_start_xmit+0x307/0x660
  [<c079bb71>] sch_direct_xmit+0xa1/0x1e0
  [<c0784bb3>] dev_queue_xmit+0x183/0x730
  [<c078c27a>] neigh_resolve_output+0xfa/0x1e0
  [<c07b436a>] ip_finish_output+0x24a/0x460
  [<c07b4897>] ip_output+0xb7/0x100
  [<c07b2d60>] ip_local_out+0x20/0x60
  [<c07e01ff>] igmpv3_sendpack+0x4f/0x60
  [<c07e108f>] igmp_ifc_timer_expire+0x29f/0x330
  [<c04520fc>] run_timer_softirq+0x15c/0x2f0
  [<c0449e3e>] __do_softirq+0xae/0x1e0
irq event stamp: 18380437
hardirqs last  enabled at (18380437): [<c0526027>] __slab_alloc.clone.3+0x67/0x5f0
hardirqs last disabled at (18380436): [<c0525ff3>] __slab_alloc.clone.3+0x33/0x5f0
softirqs last  enabled at (18377616): [<c0449eb3>] __do_softirq+0x123/0x1e0
softirqs last disabled at (18377611): [<c041278d>] do_softirq+0x9d/0xe0

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&intf->seqlock)->rlock);
  <Interrupt>
    lock(&(&intf->seqlock)->rlock);

 *** DEADLOCK ***

4 locks held by kworker/u:2/30374:
 #0:  (wiphy_name(local->hw.wiphy)){++++.+}, at: [<c045cf99>] process_one_work+0x109/0x3f0
 #1:  ((&sdata->work)){+.+.+.}, at: [<c045cf99>] process_one_work+0x109/0x3f0
 #2:  (&ifibss->mtx){+.+.+.}, at: [<f98f005b>] ieee80211_ibss_work+0x1b/0x470 [mac80211]
 #3:  (&intf->beacon_skb_mutex){+.+...}, at: [<f997a644>] rt2x00queue_update_beacon+0x24/0x50 [rt2x00lib]

stack backtrace:
Pid: 30374, comm: kworker/u:2 Not tainted 3.4.0-wl+ #4
Call Trace:
 [<c04962a6>] print_usage_bug+0x1f6/0x220
 [<c0496a12>] mark_lock+0x2c2/0x300
 [<c0495ff0>] ? check_usage_forwards+0xc0/0xc0
 [<c04978ec>] __lock_acquire+0x4bc/0x1050
 [<c0527890>] ? __kmalloc_track_caller+0x1c0/0x1d0
 [<c0777fb6>] ? copy_skb_header+0x26/0x90
 [<c0498504>] lock_acquire+0x84/0xf0
 [<f9979a20>] ? rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
 [<c0835733>] _raw_spin_lock+0x33/0x40
 [<f9979a20>] ? rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
 [<f9979a20>] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
 [<f997a5cf>] rt2x00queue_update_beacon_locked+0x5f/0xb0 [rt2x00lib]
 [<f997a64d>] rt2x00queue_update_beacon+0x2d/0x50 [rt2x00lib]
 [<f9977e3a>] rt2x00mac_bss_info_changed+0x1ca/0x200 [rt2x00lib]
 [<f9977c70>] ? rt2x00mac_remove_interface+0x70/0x70 [rt2x00lib]
 [<f98e4dd0>] ieee80211_bss_info_change_notify+0xe0/0x1d0 [mac80211]
 [<f98ef7b8>] __ieee80211_sta_join_ibss+0x3b8/0x610 [mac80211]
 [<c0496ab4>] ? mark_held_locks+0x64/0xc0
 [<c0440012>] ? virt_efi_query_capsule_caps+0x12/0x50
 [<f98efb09>] ieee80211_sta_join_ibss+0xf9/0x140 [mac80211]
 [<f98f0456>] ieee80211_ibss_work+0x416/0x470 [mac80211]
 [<c0496d8b>] ? trace_hardirqs_on+0xb/0x10
 [<c077683b>] ? skb_dequeue+0x4b/0x70
 [<f98f207f>] ieee80211_iface_work+0x13f/0x230 [mac80211]
 [<c045cf99>] ? process_one_work+0x109/0x3f0
 [<c045d015>] process_one_work+0x185/0x3f0
 [<c045cf99>] ? process_one_work+0x109/0x3f0
 [<f98f1f40>] ? ieee80211_teardown_sdata+0xa0/0xa0 [mac80211]
 [<c045ed86>] worker_thread+0x116/0x270
 [<c045ec70>] ? manage_workers+0x1e0/0x1e0
 [<c0462f64>] kthread+0x84/0x90
 [<c0462ee0>] ? __init_kthread_worker+0x60/0x60
 [<c083d382>] kernel_thread_helper+0x6/0x10

Cc: stable@vger.kernel.org
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Helmut Schaa <helmut.schaa@googlemail.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2012-06-04 15:26:26 -04:00
..
Kconfig rt2x00:Fix typo 2012-02-22 14:47:37 -05:00
Makefile
rt2x00.h rt2x00: use atomic variable for seqno 2012-06-04 15:26:26 -04:00
rt2x00config.c rt2x00: configure different txdesc parameters for non HT channel 2012-04-11 16:23:44 -04:00
rt2x00crypto.c
rt2x00debug.c rt2x00: Add debugfs access for rfcsr register 2012-05-08 21:53:46 -04:00
rt2x00debug.h rt2x00: Add debugfs access for rfcsr register 2012-05-08 21:53:46 -04:00
rt2x00dev.c rt2x00: Use GFP_KERNEL for rx buffer allocation on USB devices 2012-04-23 15:35:29 -04:00
rt2x00dump.h
rt2x00firmware.c
rt2x00leds.c rt2x00: increase led's name buffer length 2012-04-09 16:09:34 -04:00
rt2x00leds.h
rt2x00lib.h rt2x00: Use GFP_KERNEL for rx buffer allocation on USB devices 2012-04-23 15:35:29 -04:00
rt2x00link.c rt2x00:Add VCO recalibration 2012-02-27 14:05:44 -05:00
rt2x00mac.c rt2x00: use atomic variable for seqno 2012-06-04 15:26:26 -04:00
rt2x00pci.c rt2x00: Use GFP_KERNEL for rx buffer allocation on USB devices 2012-04-23 15:35:29 -04:00
rt2x00pci.h
rt2x00queue.c rt2x00: use atomic variable for seqno 2012-06-04 15:26:26 -04:00
rt2x00queue.h rt2x00: rt2800usb: rework txstatus code 2012-03-15 13:40:31 -04:00
rt2x00reg.h
rt2x00soc.c
rt2x00soc.h
rt2x00usb.c rt2x00: Use GFP_KERNEL for rx buffer allocation on USB devices 2012-04-23 15:35:29 -04:00
rt2x00usb.h
rt61pci.c net/wireless: use module_pci_driver 2012-04-16 14:38:50 -04:00
rt61pci.h
rt73usb.c USB 3.5-rc1 pull request 2012-05-22 15:50:46 -07:00
rt73usb.h
rt2400pci.c net/wireless: use module_pci_driver 2012-04-16 14:38:50 -04:00
rt2400pci.h
rt2500pci.c net/wireless: use module_pci_driver 2012-04-16 14:38:50 -04:00
rt2500pci.h
rt2500usb.c USB 3.5-rc1 pull request 2012-05-22 15:50:46 -07:00
rt2500usb.h
rt2800.h rt2x00: Add debugfs access for rfcsr register 2012-05-08 21:53:46 -04:00
rt2800lib.c rt2x00: Add debugfs access for rfcsr register 2012-05-08 21:53:46 -04:00
rt2800lib.h rt2800: introduce wpdma_disable function 2012-04-13 14:32:47 -04:00
rt2800pci.c rt2x00:Add RT539b chipset support 2012-05-16 12:46:37 -04:00
rt2800pci.h
rt2800usb.c USB 3.5-rc1 pull request 2012-05-22 15:50:46 -07:00
rt2800usb.h