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Eliad Peller c229e2f6ba cfg80211: fix potential deadlock in regulatory 
commit fe20b39ec3 upstream.

reg_timeout_work() calls restore_regulatory_settings() which
takes cfg80211_mutex.

reg_set_request_processed() already holds cfg80211_mutex
before calling cancel_delayed_work_sync(reg_timeout),
so it might deadlock.

Call the async cancel_delayed_work instead, in order
to avoid the potential deadlock.

This is the relevant lockdep warning:

cfg80211: Calling CRDA for country: XX

======================================================
[ INFO: possible circular locking dependency detected ]
3.4.0-rc5-wl+ #26 Not tainted
-------------------------------------------------------
kworker/0:2/1391 is trying to acquire lock:
 (cfg80211_mutex){+.+.+.}, at: [<bf28ae00>] restore_regulatory_settings+0x34/0x418 [cfg80211]

but task is already holding lock:
 ((reg_timeout).work){+.+...}, at: [<c0059e94>] process_one_work+0x1f0/0x480

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 ((reg_timeout).work){+.+...}:
       [<c008fd44>] validate_chain+0xb94/0x10f0
       [<c0090b68>] __lock_acquire+0x8c8/0x9b0
       [<c0090d40>] lock_acquire+0xf0/0x114
       [<c005b600>] wait_on_work+0x4c/0x154
       [<c005c000>] __cancel_work_timer+0xd4/0x11c
       [<c005c064>] cancel_delayed_work_sync+0x1c/0x20
       [<bf28b274>] reg_set_request_processed+0x50/0x78 [cfg80211]
       [<bf28bd84>] set_regdom+0x550/0x600 [cfg80211]
       [<bf294cd8>] nl80211_set_reg+0x218/0x258 [cfg80211]
       [<c03c7738>] genl_rcv_msg+0x1a8/0x1e8
       [<c03c6a00>] netlink_rcv_skb+0x5c/0xc0
       [<c03c7584>] genl_rcv+0x28/0x34
       [<c03c6720>] netlink_unicast+0x15c/0x228
       [<c03c6c7c>] netlink_sendmsg+0x218/0x298
       [<c03933c8>] sock_sendmsg+0xa4/0xc0
       [<c039406c>] __sys_sendmsg+0x1e4/0x268
       [<c0394228>] sys_sendmsg+0x4c/0x70
       [<c0013840>] ret_fast_syscall+0x0/0x3c

-> #1 (reg_mutex){+.+.+.}:
       [<c008fd44>] validate_chain+0xb94/0x10f0
       [<c0090b68>] __lock_acquire+0x8c8/0x9b0
       [<c0090d40>] lock_acquire+0xf0/0x114
       [<c04734dc>] mutex_lock_nested+0x48/0x320
       [<bf28b2cc>] reg_todo+0x30/0x538 [cfg80211]
       [<c0059f44>] process_one_work+0x2a0/0x480
       [<c005a4b4>] worker_thread+0x1bc/0x2bc
       [<c0061148>] kthread+0x98/0xa4
       [<c0014af4>] kernel_thread_exit+0x0/0x8

-> #0 (cfg80211_mutex){+.+.+.}:
       [<c008ed58>] print_circular_bug+0x68/0x2cc
       [<c008fb28>] validate_chain+0x978/0x10f0
       [<c0090b68>] __lock_acquire+0x8c8/0x9b0
       [<c0090d40>] lock_acquire+0xf0/0x114
       [<c04734dc>] mutex_lock_nested+0x48/0x320
       [<bf28ae00>] restore_regulatory_settings+0x34/0x418 [cfg80211]
       [<bf28b200>] reg_timeout_work+0x1c/0x20 [cfg80211]
       [<c0059f44>] process_one_work+0x2a0/0x480
       [<c005a4b4>] worker_thread+0x1bc/0x2bc
       [<c0061148>] kthread+0x98/0xa4
       [<c0014af4>] kernel_thread_exit+0x0/0x8

other info that might help us debug this:

Chain exists of:
  cfg80211_mutex --> reg_mutex --> (reg_timeout).work

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock((reg_timeout).work);
                               lock(reg_mutex);
                               lock((reg_timeout).work);
  lock(cfg80211_mutex);

 *** DEADLOCK ***

2 locks held by kworker/0:2/1391:
 #0:  (events){.+.+.+}, at: [<c0059e94>] process_one_work+0x1f0/0x480
 #1:  ((reg_timeout).work){+.+...}, at: [<c0059e94>] process_one_work+0x1f0/0x480

stack backtrace:
[<c001b928>] (unwind_backtrace+0x0/0x12c) from [<c0471d3c>] (dump_stack+0x20/0x24)
[<c0471d3c>] (dump_stack+0x20/0x24) from [<c008ef70>] (print_circular_bug+0x280/0x2cc)
[<c008ef70>] (print_circular_bug+0x280/0x2cc) from [<c008fb28>] (validate_chain+0x978/0x10f0)
[<c008fb28>] (validate_chain+0x978/0x10f0) from [<c0090b68>] (__lock_acquire+0x8c8/0x9b0)
[<c0090b68>] (__lock_acquire+0x8c8/0x9b0) from [<c0090d40>] (lock_acquire+0xf0/0x114)
[<c0090d40>] (lock_acquire+0xf0/0x114) from [<c04734dc>] (mutex_lock_nested+0x48/0x320)
[<c04734dc>] (mutex_lock_nested+0x48/0x320) from [<bf28ae00>] (restore_regulatory_settings+0x34/0x418 [cfg80211])
[<bf28ae00>] (restore_regulatory_settings+0x34/0x418 [cfg80211]) from [<bf28b200>] (reg_timeout_work+0x1c/0x20 [cfg80211])
[<bf28b200>] (reg_timeout_work+0x1c/0x20 [cfg80211]) from [<c0059f44>] (process_one_work+0x2a0/0x480)
[<c0059f44>] (process_one_work+0x2a0/0x480) from [<c005a4b4>] (worker_thread+0x1bc/0x2bc)
[<c005a4b4>] (worker_thread+0x1bc/0x2bc) from [<c0061148>] (kthread+0x98/0xa4)
[<c0061148>] (kthread+0x98/0xa4) from [<c0014af4>] (kernel_thread_exit+0x0/0x8)
cfg80211: Calling CRDA to update world regulatory domain
cfg80211: World regulatory domain updated:
cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
cfg80211:   (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
cfg80211:   (2457000 KHz - 2482000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
cfg80211:   (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
cfg80211:   (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
cfg80211:   (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)

Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-16 08:47:48 -07:00
..
9p net/9p: Fix kernel crash with msize 512K 2011-10-03 11:40:22 -07:00
802 snap: remove one synchronize_net() 2011-05-23 16:29:24 -04:00
8021q Revert "net: maintain namespace isolation between vlan and real device" 2012-06-10 00:33:03 +09:00
appletalk appletalk: Fix OOPS in atalk_release(). 2011-03-31 18:59:10 -07:00
atm net: fix NULL dereferences in check_peer_redir() 2012-02-13 11:06:13 -08:00
ax25 net ax25: Reorder ax25_exit to remove races. 2012-04-27 09:51:21 -07:00
batman-adv Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6 2011-05-20 13:43:21 -07:00
bluetooth Bluetooth: hci_core: fix NULL-pointer dereference at unregister 2012-04-22 16:21:42 -07:00
bridge bridge: Assign rtnl_link_ops to bridge devices created via ioctl (v2) 2012-07-16 08:47:37 -07:00
caif net caif: Register properly as a pernet subsystem. 2012-02-03 09:19:03 -08:00
can can bcm: fix incomplete tx_setup fix 2011-11-11 09:36:45 -08:00
ceph ceph: fix file mode calculation 2011-07-19 11:25:04 -07:00
core netpoll: fix netpoll_send_udp() bugs 2012-07-16 08:47:38 -07:00
dcb net: dcbnl: Update copyright dates 2011-03-14 17:02:42 -07:00
dccp net: Compute protocol sequence numbers and fragment IDs using MD5. 2011-08-15 18:31:35 -07:00
decnet net: fix NULL dereferences in check_peer_redir() 2012-02-13 11:06:13 -08:00
dns_resolver KEYS: Improve /proc/keys 2011-03-17 11:59:32 +11:00
dsa Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2011-05-05 14:59:02 -07:00
econet econet: Fix set-but-unused variable. 2011-04-17 00:15:22 -07:00
ethernet net: add IFF_SKB_TX_SHARED flag to priv_flags 2011-08-15 18:31:38 -07:00
ieee802154 ieee802154: Don't leak memory in ieee802154_nl_fill_phy 2011-06-13 18:03:22 -04:00
ipv4 xfrm: take net hdr len into account for esp payload size calculation 2012-06-10 00:33:03 +09:00
ipv6 ipv6: Move ipv6 proc file registration to end of init order 2012-07-16 08:47:37 -07:00
ipx ipx: fix ipx_release() 2011-03-21 18:16:39 -07:00
irda irda: iriap: Use seperate lockdep class for irias_objects->hb_spinlock 2011-06-06 17:00:35 -07:00
iucv [S390] irq: merge irq.c and s390_ext.c 2011-05-26 09:48:24 +02:00
key net: convert %p usage to %pK 2011-05-24 01:13:12 -04:00
l2tp net: l2tp_eth: fix kernel panic on rmmod l2tp_eth 2012-07-16 08:47:36 -07:00
lapb Net: lapb: Makefile: Remove deprecated kbuild goal definitions 2010-11-22 08:16:14 -08:00
llc llc: llc_cmsg_rcv was getting called after sk_eat_skb. 2012-01-06 14:14:06 -08:00
mac80211 mac80211: clean up remain-on-channel on interface stop 2012-06-17 11:23:10 -07:00
netfilter ipvs: fix matching of fwmark templates during scheduling 2012-02-29 16:34:31 -08:00
netlabel Remove prefetch() from <linux/skbuff.h> and "netlabel_addrlist.h" 2011-05-22 21:43:41 -07:00
netlink netlink: fix races after skb queueing 2012-04-27 09:51:19 -07:00
netrom NET: AX.25, NETROM, ROSE: Remove SOCK_DEBUG calls 2011-04-14 00:20:07 -07:00
packet make PACKET_STATISTICS getsockopt report consistently between ring and non-ring 2011-11-11 09:36:29 -08:00
phonet phonet: Check input from user before allocating 2012-04-27 09:51:19 -07:00
rds Remove printk from rds_sendmsg 2012-04-02 09:27:21 -07:00
rfkill net: rfkill: add generic gpio rfkill driver 2011-05-19 13:53:54 -04:00
rose rose_dev: fix memcpy-bug in rose_set_mac_address 2012-04-13 08:14:05 -07:00
rxrpc rxrpc: Fix set but unused variable 'usage' in rxrpc_get_transport() 2011-05-19 18:51:50 -04:00
sched netem: fix possible skb leak 2012-05-21 09:39:59 -07:00
sctp sctp: check cached dst before using it 2012-06-10 00:33:03 +09:00
sunrpc NFSv4.1: Fix a request leak on the back channel 2012-06-22 11:34:13 -07:00
tipc tipc: Revise timings used when sending link request messages 2011-05-10 16:04:02 -04:00
unix net: convert %p usage to %pK 2011-05-24 01:13:12 -04:00
wanrouter Fix common misspellings 2011-03-31 11:26:23 -03:00
wimax
wireless cfg80211: fix potential deadlock in regulatory 2012-07-16 08:47:48 -07:00
x25 x25: Prevent skb overreads when checking call user data 2011-10-25 07:10:17 +02:00
xfrm ipv6: fix incorrect ipsec fragment 2012-06-10 00:33:02 +09:00
compat.c net: Add sendmmsg socket system call 2011-05-05 11:10:14 -07:00
Kconfig bpf: depends on MODULES 2011-04-29 10:20:53 -07:00
Makefile net: Enter net/ipv6/ even if CONFIG_IPV6=n 2011-03-07 12:50:52 -08:00
nonet.c llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
socket.c tcp: allow splice() to build full TSO packets 2012-04-27 09:51:18 -07:00
sysctl_net.c
TUNABLE