linux/net
Stanislaw Gruszka c74f2b2678 genetlink: release cb_lock before requesting additional module
Requesting external module with cb_lock taken can result in
the deadlock like showed below:

[ 2458.111347] Showing all locks held in the system:
[ 2458.111347] 1 lock held by NetworkManager/582:
[ 2458.111347]  #0:  (cb_lock){++++++}, at: [<ffffffff8162bc79>] genl_rcv+0x19/0x40
[ 2458.111347] 1 lock held by modprobe/603:
[ 2458.111347]  #0:  (cb_lock){++++++}, at: [<ffffffff8162baa5>] genl_lock_all+0x15/0x30

[ 2461.579457] SysRq : Show Blocked State
[ 2461.580103]   task                        PC stack   pid father
[ 2461.580103] NetworkManager  D ffff880034b84500  4040   582      1 0x00000080
[ 2461.580103]  ffff8800197ff720 0000000000000046 00000000001d5340 ffff8800197fffd8
[ 2461.580103]  ffff8800197fffd8 00000000001d5340 ffff880019631700 7fffffffffffffff
[ 2461.580103]  ffff8800197ff880 ffff8800197ff878 ffff880019631700 ffff880019631700
[ 2461.580103] Call Trace:
[ 2461.580103]  [<ffffffff817355f9>] schedule+0x29/0x70
[ 2461.580103]  [<ffffffff81731ad1>] schedule_timeout+0x1c1/0x360
[ 2461.580103]  [<ffffffff810e69eb>] ? mark_held_locks+0xbb/0x140
[ 2461.580103]  [<ffffffff817377ac>] ? _raw_spin_unlock_irq+0x2c/0x50
[ 2461.580103]  [<ffffffff810e6b6d>] ? trace_hardirqs_on_caller+0xfd/0x1c0
[ 2461.580103]  [<ffffffff81736398>] wait_for_completion_killable+0xe8/0x170
[ 2461.580103]  [<ffffffff810b7fa0>] ? wake_up_state+0x20/0x20
[ 2461.580103]  [<ffffffff81095825>] call_usermodehelper_exec+0x1a5/0x210
[ 2461.580103]  [<ffffffff817362ed>] ? wait_for_completion_killable+0x3d/0x170
[ 2461.580103]  [<ffffffff81095cc3>] __request_module+0x1b3/0x370
[ 2461.580103]  [<ffffffff810e6b6d>] ? trace_hardirqs_on_caller+0xfd/0x1c0
[ 2461.580103]  [<ffffffff8162c5c9>] ctrl_getfamily+0x159/0x190
[ 2461.580103]  [<ffffffff8162d8a4>] genl_family_rcv_msg+0x1f4/0x2e0
[ 2461.580103]  [<ffffffff8162d990>] ? genl_family_rcv_msg+0x2e0/0x2e0
[ 2461.580103]  [<ffffffff8162da1e>] genl_rcv_msg+0x8e/0xd0
[ 2461.580103]  [<ffffffff8162b729>] netlink_rcv_skb+0xa9/0xc0
[ 2461.580103]  [<ffffffff8162bc88>] genl_rcv+0x28/0x40
[ 2461.580103]  [<ffffffff8162ad6d>] netlink_unicast+0xdd/0x190
[ 2461.580103]  [<ffffffff8162b149>] netlink_sendmsg+0x329/0x750
[ 2461.580103]  [<ffffffff815db849>] sock_sendmsg+0x99/0xd0
[ 2461.580103]  [<ffffffff810bb58f>] ? local_clock+0x5f/0x70
[ 2461.580103]  [<ffffffff810e96e8>] ? lock_release_non_nested+0x308/0x350
[ 2461.580103]  [<ffffffff815dbc6e>] ___sys_sendmsg+0x39e/0x3b0
[ 2461.580103]  [<ffffffff810565af>] ? kvm_clock_read+0x2f/0x50
[ 2461.580103]  [<ffffffff810218b9>] ? sched_clock+0x9/0x10
[ 2461.580103]  [<ffffffff810bb2bd>] ? sched_clock_local+0x1d/0x80
[ 2461.580103]  [<ffffffff810bb448>] ? sched_clock_cpu+0xa8/0x100
[ 2461.580103]  [<ffffffff810e33ad>] ? trace_hardirqs_off+0xd/0x10
[ 2461.580103]  [<ffffffff810bb58f>] ? local_clock+0x5f/0x70
[ 2461.580103]  [<ffffffff810e3f7f>] ? lock_release_holdtime.part.28+0xf/0x1a0
[ 2461.580103]  [<ffffffff8120fec9>] ? fget_light+0xf9/0x510
[ 2461.580103]  [<ffffffff8120fe0c>] ? fget_light+0x3c/0x510
[ 2461.580103]  [<ffffffff815dd1d2>] __sys_sendmsg+0x42/0x80
[ 2461.580103]  [<ffffffff815dd222>] SyS_sendmsg+0x12/0x20
[ 2461.580103]  [<ffffffff81741ad9>] system_call_fastpath+0x16/0x1b
[ 2461.580103] modprobe        D ffff88000f2c8000  4632   603    602 0x00000080
[ 2461.580103]  ffff88000f04fba8 0000000000000046 00000000001d5340 ffff88000f04ffd8
[ 2461.580103]  ffff88000f04ffd8 00000000001d5340 ffff8800377d4500 ffff8800377d4500
[ 2461.580103]  ffffffff81d0b260 ffffffff81d0b268 ffffffff00000000 ffffffff81d0b2b0
[ 2461.580103] Call Trace:
[ 2461.580103]  [<ffffffff817355f9>] schedule+0x29/0x70
[ 2461.580103]  [<ffffffff81736d4d>] rwsem_down_write_failed+0xed/0x1a0
[ 2461.580103]  [<ffffffff810bb200>] ? update_cpu_load_active+0x10/0xb0
[ 2461.580103]  [<ffffffff8137b473>] call_rwsem_down_write_failed+0x13/0x20
[ 2461.580103]  [<ffffffff8173492d>] ? down_write+0x9d/0xb2
[ 2461.580103]  [<ffffffff8162baa5>] ? genl_lock_all+0x15/0x30
[ 2461.580103]  [<ffffffff8162baa5>] genl_lock_all+0x15/0x30
[ 2461.580103]  [<ffffffff8162cbb3>] genl_register_family+0x53/0x1f0
[ 2461.580103]  [<ffffffffa01dc000>] ? 0xffffffffa01dbfff
[ 2461.580103]  [<ffffffff8162d650>] genl_register_family_with_ops+0x20/0x80
[ 2461.580103]  [<ffffffffa01dc000>] ? 0xffffffffa01dbfff
[ 2461.580103]  [<ffffffffa017fe84>] nl80211_init+0x24/0xf0 [cfg80211]
[ 2461.580103]  [<ffffffffa01dc000>] ? 0xffffffffa01dbfff
[ 2461.580103]  [<ffffffffa01dc043>] cfg80211_init+0x43/0xdb [cfg80211]
[ 2461.580103]  [<ffffffff810020fa>] do_one_initcall+0xfa/0x1b0
[ 2461.580103]  [<ffffffff8105cb93>] ? set_memory_nx+0x43/0x50
[ 2461.580103]  [<ffffffff810f75af>] load_module+0x1c6f/0x27f0
[ 2461.580103]  [<ffffffff810f2c90>] ? store_uevent+0x40/0x40
[ 2461.580103]  [<ffffffff810f82c6>] SyS_finit_module+0x86/0xb0
[ 2461.580103]  [<ffffffff81741ad9>] system_call_fastpath+0x16/0x1b
[ 2461.580103] Sched Debug Version: v0.10, 3.11.0-0.rc1.git4.1.fc20.x86_64 #1

Problem start to happen after adding net-pf-16-proto-16-family-nl80211
alias name to cfg80211 module by below commit (though that commit
itself is perfectly fine):

commit fb4e156886
Author: Marcel Holtmann <marcel@holtmann.org>
Date:   Sun Apr 28 16:22:06 2013 -0700

    nl80211: Add generic netlink module alias for cfg80211/nl80211

Reported-and-tested-by: Jeff Layton <jlayton@redhat.com>
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Reviewed-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-07-27 22:19:20 -07:00
..
9p Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-07-13 17:42:22 -07:00
802 net/802/mrp: fix lockdep splat 2013-05-14 13:02:30 -07:00
8021q vlan: fix a race in egress prio management 2013-07-18 13:07:13 -07:00
appletalk net: pass info struct via netdevice notifier 2013-05-28 13:11:01 -07:00
atm net: always pass struct netdev_notifier_info to netdevice notifiers 2013-05-28 21:58:54 -07:00
ax25 net: Convert uses of typedef ctl_table to struct ctl_table 2013-06-13 02:36:09 -07:00
batman-adv net: Unmap fragment page once iterator is done 2013-06-24 01:46:01 -07:00
bluetooth Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-07-09 18:24:39 -07:00
bridge bridge: do not call setup_timer() multiple times 2013-07-19 22:12:42 -07:00
caif net: pass info struct via netdevice notifier 2013-05-28 13:11:01 -07:00
can net: pass info struct via netdevice notifier 2013-05-28 13:11:01 -07:00
ceph libceph: call r_unsafe_callback when unsafe reply is received 2013-07-03 15:32:58 -07:00
core neigh: prevent overflowing params in /proc/sys/net/ipv4/neigh/ 2013-07-26 14:22:10 -07:00
dcb rtnetlink: Remove passing of attributes into rtnl_doit functions 2013-03-22 10:31:16 -04:00
dccp tcp: Remove TCPCT 2013-03-17 14:35:13 -04:00
decnet net: Convert uses of typedef ctl_table to struct ctl_table 2013-06-13 02:36:09 -07:00
dns_resolver net: strict_strtoul is obsolete, use kstrtoul instead 2013-07-12 16:09:14 -07:00
dsa dsa: fix freeing of sparse port allocation 2013-03-25 12:23:41 -04:00
ethernet net: Fix sysfs_format_mac() code duplication. 2013-07-16 17:09:22 -07:00
ieee802154 net: pass info struct via netdevice notifier 2013-05-28 13:11:01 -07:00
ipv4 fib_trie: potential out of bounds access in trie_show_stats() 2013-07-24 16:05:14 -07:00
ipv6 ipv6: take rtnl_lock and mark mrt6 table as freed on namespace cleanup 2013-07-24 17:02:13 -07:00
ipx net: pass info struct via netdevice notifier 2013-05-28 13:11:01 -07:00
irda net/irda: fixed style issues in irlan_eth 2013-07-16 12:16:03 -07:00
iucv net: delete __cpuinit usage from all net files 2013-07-14 19:36:58 -04:00
key af_key: fix info leaks in notify messages 2013-06-26 15:15:54 -07:00
l2tp l2tp: make datapath resilient to packet loss when sequence numbers enabled 2013-07-02 16:33:25 -07:00
lapb
llc llc: Fix missing msg_namelen update in llc_ui_recvmsg() 2013-04-07 16:28:01 -04:00
mac80211 mac80211/minstrel: fix NULL pointer dereference issue 2013-07-16 17:48:14 +03:00
mac802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-04-30 03:55:20 -04:00
mpls MPLS: Add limited GSO support 2013-05-27 22:50:59 -07:00
netfilter netfilter: xt_socket: fix broken v0 support 2013-07-15 11:15:21 +02:00
netlabel net: pass info struct via netdevice notifier 2013-05-28 13:11:01 -07:00
netlink genetlink: release cb_lock before requesting additional module 2013-07-27 22:19:20 -07:00
netrom net: Convert uses of typedef ctl_table to struct ctl_table 2013-06-13 02:36:09 -07:00
nfc NFC: llcp: Fix the well known services endianness 2013-06-14 13:45:10 +02:00
openvswitch openvswitch: Add Kconfig dependency on GRE-DEMUX. 2013-07-01 13:19:43 -07:00
packet Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-06-19 16:49:39 -07:00
phonet net: Convert uses of typedef ctl_table to struct ctl_table 2013-06-13 02:36:09 -07:00
rds net: Convert uses of typedef ctl_table to struct ctl_table 2013-06-13 02:36:09 -07:00
rfkill Merge branch 'for-john' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next 2013-04-22 14:58:14 -04:00
rose net: Convert uses of typedef ctl_table to struct ctl_table 2013-06-13 02:36:09 -07:00
rxrpc Driver core patches for 3.9-rc1 2013-02-21 12:05:51 -08:00
sched pkt_sched: sch_qfq: remove a source of high packet delay/jitter 2013-07-18 13:02:00 -07:00
sctp net: sctp: confirm route during forward progress 2013-07-09 12:49:56 -07:00
sunrpc Merge branch 'for-3.11' of git://linux-nfs.org/~bfields/linux 2013-07-17 13:43:55 -07:00
tipc net/tipc: use %*phC to dump small buffers in hex form 2013-07-11 17:03:36 -07:00
unix Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-07-09 18:24:39 -07:00
vmw_vsock VSOCK: Fix VSOCK_HASH and VSOCK_CONN_HASH 2013-06-23 23:51:48 -07:00
wimax
wireless nl80211: fix the setting of RSSI threshold value for mesh 2013-07-16 09:55:58 +03:00
x25 x25: Fix broken locking in ioctl error paths. 2013-07-01 18:15:25 -07:00
xfrm Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2013-06-26 13:23:13 -07:00
compat.c net: Unbreak compat_sys_{send,recv}msg 2013-06-06 11:52:14 -07:00
Kconfig Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-07-09 18:24:39 -07:00
Makefile MPLS: Add limited GSO support 2013-05-27 22:50:59 -07:00
nonet.c
socket.c net: rename busy poll socket op and globals 2013-07-10 17:08:27 -07:00
sysctl_net.c