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fe20b39ec3
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Eliad Peller fe20b39ec3 cfg80211: fix potential deadlock in regulatory 
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)

Cc: stable@kernel.org
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2012-06-13 10:17:53 +02:00
..
9p Autogenerated GPG tag for Rusty D1ADB8F1: 15EE 8D6C AB0E 7F0C F999 BFCB D920 0E6C D1AD B8F1 2012-05-21 20:20:23 -07:00
802 tokenring: delete all remaining driver support 2012-05-15 20:23:16 -04:00
8021q Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-05-16 22:17:37 -04:00
appletalk net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
atm Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-05-22 19:22:50 -07:00
ax25 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-04-23 23:15:17 -04:00
batman-adv batman-adv: unset the TT_CLIENT_PENDING flag if the new local entry already exists 2012-05-14 09:05:08 +02:00
bluetooth Bluetooth: Fix checking the wrong flag when accepting a socket 2012-06-05 06:26:26 +03:00
bridge ipv6: correct the ipv6 option name - Pad0 to Pad1 2012-05-17 15:49:51 -04:00
caif Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-05-22 19:22:50 -07:00
can can: fix sparse warning for cgw_list 2012-04-16 21:08:18 +02:00
ceph Merge git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client 2012-05-30 11:17:19 -07:00
core net: sock: validate data_len before allocating skb in sock_alloc_send_pskb() 2012-05-31 18:22:45 -04:00
dcb net: dcb: add CEE notify calls 2012-04-25 19:47:17 -04:00
dccp net: include/net/sock.h cleanup 2012-05-17 04:50:21 -04:00
decnet net: Convert net_ratelimit uses to net_<level>_ratelimited 2012-05-15 13:45:03 -04:00
dns_resolver Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2012-05-21 20:27:36 -07:00
dsa dsa: Convert compare_ether_addr to ether_addr_equal 2012-05-09 20:49:19 -04:00
ethernet net, drivers/net: Convert compare_ether_addr_64bits to ether_addr_equal_64bits 2012-05-10 23:33:01 -04:00
ieee802154 ieee802154: interface type to be added 2012-05-16 15:17:08 -04:00
ipv4 tcp: reflect SYN queue_mapping into SYNACK packets 2012-06-01 14:22:11 -04:00
ipv6 tcp: reflect SYN queue_mapping into SYNACK packets 2012-06-01 14:22:11 -04:00
ipx ipx: Remove spurious NULL checking in ipx_ioctl(). 2012-05-19 00:51:04 -04:00
irda net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
iucv Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2012-03-22 18:15:32 -07:00
key net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
l2tp genetlink: Build a generic netlink family module alias 2012-05-29 22:33:56 -04:00
lapb lapb: Neaten debugging 2012-05-17 18:45:20 -04:00
llc net: include/net/sock.h cleanup 2012-05-17 04:50:21 -04:00
mac80211 mac80211: add missing kernel-doc 2012-06-12 13:56:41 +02:00
mac802154 mac802154: monitor device support 2012-05-16 15:17:08 -04:00
netfilter Merge branch 'for-3.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu 2012-05-22 17:37:47 -07:00
netlabel netlabel: use GFP flags from caller instead of GFP_ATOMIC 2012-03-22 19:29:57 -04:00
netlink genetlink: Build a generic netlink family module alias 2012-05-29 22:33:56 -04:00
netrom net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
nfc NFC: Fix possible NULL ptr deref when getting the name of a socket 2012-06-08 13:47:07 -04:00
openvswitch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-05-16 22:17:37 -04:00
packet af_packet: packet_getsockopt() cleanup 2012-04-21 16:36:42 -04:00
phonet net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
rds rds_rdma: don't assume infiniband device is PCI 2012-05-29 17:30:07 -04:00
rfkill device.h: cleanup users outside of linux/include (C files) 2012-03-11 14:27:37 -04:00
rose net: Convert all sysctl registrations to register_net_sysctl 2012-04-20 21:22:30 -04:00
rxrpc net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
sched sch_atm.c: get rid of poinless extern 2012-06-01 10:37:18 -04:00
sctp Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-05-16 22:17:37 -04:00
sunrpc Merge branch 'for-3.5' of git://linux-nfs.org/~bfields/linux 2012-06-01 08:32:58 -07:00
tipc tipc: compress out gratuitous extra carriage returns 2012-04-30 15:53:56 -04:00
unix net: sock_diag_handler structs can be const 2012-04-25 20:46:59 -04:00
wanrouter net/wanrouter: Deprecate and schedule for removal 2012-05-24 16:22:53 -04:00
wimax net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
wireless cfg80211: fix potential deadlock in regulatory 2012-06-13 10:17:53 +02:00
x25 net: add a limit parameter to sk_add_backlog() 2012-04-23 22:28:28 -04:00
xfrm ipv6: fix incorrect ipsec fragment 2012-05-27 01:11:22 -04:00
compat.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2012-05-21 20:27:36 -07:00
Kconfig net: drop NET dependency from HAVE_BPF_JIT 2012-05-21 12:50:12 -07:00
Makefile econet: remove ancient bug ridden protocol 2012-05-18 01:35:08 -04:00
nonet.c
socket.c Merge branch 'for-3.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu 2012-05-22 17:37:47 -07:00
sysctl_net.c net: delete all instances of special processing for token ring 2012-05-15 20:14:35 -04:00