forked from luck/tmp_suning_uos_patched
4f919a3bc5
I previously managed to reproduce a hang while scanning wireless channels (reproducible with airodump-ng hopping channels); subsequent lockdep instrumentation revealed a lock ordering issue. Without knowing the design intent, it looks like the locks should be taken in reverse order; please comment. ======================================================= [ INFO: possible circular locking dependency detected ] 2.6.38-rc5-341cd #4 ------------------------------------------------------- airodump-ng/15445 is trying to acquire lock: (&rdev->devlist_mtx){+.+.+.}, at: [<ffffffff816b1266>] cfg80211_wext_siwfreq+0xc6/0x100 but task is already holding lock: (&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>] cfg80211_wext_siwfreq+0xbc/0x100 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&wdev->mtx){+.+.+.}: [<ffffffff810a79d6>] lock_acquire+0xc6/0x280 [<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0 [<ffffffff81696080>] cfg80211_netdev_notifier_call+0x430/0x5f0 [<ffffffff8109351b>] notifier_call_chain+0x8b/0x100 [<ffffffff810935b1>] raw_notifier_call_chain+0x11/0x20 [<ffffffff81576d92>] call_netdevice_notifiers+0x32/0x60 [<ffffffff815771a4>] __dev_notify_flags+0x34/0x80 [<ffffffff81577230>] dev_change_flags+0x40/0x70 [<ffffffff8158587c>] do_setlink+0x1fc/0x8d0 [<ffffffff81586042>] rtnl_setlink+0xf2/0x140 [<ffffffff81586923>] rtnetlink_rcv_msg+0x163/0x270 [<ffffffff8159d741>] netlink_rcv_skb+0xa1/0xd0 [<ffffffff815867b0>] rtnetlink_rcv+0x20/0x30 [<ffffffff8159d39a>] netlink_unicast+0x2ba/0x300 [<ffffffff8159dd57>] netlink_sendmsg+0x267/0x3e0 [<ffffffff8155e364>] sock_sendmsg+0xe4/0x110 [<ffffffff8155f3a3>] sys_sendmsg+0x253/0x3b0 [<ffffffff81003192>] system_call_fastpath+0x16/0x1b -> #0 (&rdev->devlist_mtx){+.+.+.}: [<ffffffff810a7222>] __lock_acquire+0x1622/0x1d10 [<ffffffff810a79d6>] lock_acquire+0xc6/0x280 [<ffffffff816d6bce>] mutex_lock_nested+0x6e/0x4b0 [<ffffffff816b1266>] cfg80211_wext_siwfreq+0xc6/0x100 [<ffffffff816b2fad>] ioctl_standard_call+0x5d/0xd0 [<ffffffff816b3223>] T.808+0x163/0x170 [<ffffffff816b326a>] wext_handle_ioctl+0x3a/0x90 [<ffffffff815798d2>] dev_ioctl+0x6f2/0x830 [<ffffffff8155cf3d>] sock_ioctl+0xfd/0x290 [<ffffffff8117dffd>] do_vfs_ioctl+0x9d/0x590 [<ffffffff8117e53a>] sys_ioctl+0x4a/0x80 [<ffffffff81003192>] system_call_fastpath+0x16/0x1b other info that might help us debug this: 2 locks held by airodump-ng/15445: #0: (rtnl_mutex){+.+.+.}, at: [<ffffffff81586782>] rtnl_lock+0x12/0x20 #1: (&wdev->mtx){+.+.+.}, at: [<ffffffff816b125c>] cfg80211_wext_siwfreq+0xbc/0x100 stack backtrace: Pid: 15445, comm: airodump-ng Not tainted 2.6.38-rc5-341cd #4 Call Trace: [<ffffffff810a3f0a>] ? print_circular_bug+0xfa/0x100 [<ffffffff810a7222>] ? __lock_acquire+0x1622/0x1d10 [<ffffffff810a1f99>] ? trace_hardirqs_off_caller+0x29/0xc0 [<ffffffff810a79d6>] ? lock_acquire+0xc6/0x280 [<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100 [<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90 [<ffffffff816d6bce>] ? mutex_lock_nested+0x6e/0x4b0 [<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100 [<ffffffff810a31d7>] ? mark_held_locks+0x67/0x90 [<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100 [<ffffffff816b1266>] ? cfg80211_wext_siwfreq+0xc6/0x100 [<ffffffff816b2fad>] ? ioctl_standard_call+0x5d/0xd0 [<ffffffff8157818b>] ? __dev_get_by_name+0x9b/0xc0 [<ffffffff816b2f50>] ? ioctl_standard_call+0x0/0xd0 [<ffffffff816b3223>] ? T.808+0x163/0x170 [<ffffffff8112ddf2>] ? might_fault+0x72/0xd0 [<ffffffff816b326a>] ? wext_handle_ioctl+0x3a/0x90 [<ffffffff8112de3b>] ? might_fault+0xbb/0xd0 [<ffffffff815798d2>] ? dev_ioctl+0x6f2/0x830 [<ffffffff810a1bae>] ? put_lock_stats+0xe/0x40 [<ffffffff810a1c8c>] ? lock_release_holdtime+0xac/0x150 [<ffffffff8155cf3d>] ? sock_ioctl+0xfd/0x290 [<ffffffff8117dffd>] ? do_vfs_ioctl+0x9d/0x590 [<ffffffff8116c8ff>] ? fget_light+0x1df/0x3c0 [<ffffffff8117e53a>] ? sys_ioctl+0x4a/0x80 [<ffffffff81003192>] ? system_call_fastpath+0x16/0x1b Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com> |
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| .. | ||
| 9p | ||
| 802 | ||
| 8021q | ||
| appletalk | ||
| atm | ||
| ax25 | ||
| batman-adv | ||
| bluetooth | ||
| bridge | ||
| caif | ||
| can | ||
| ceph | ||
| core | ||
| dcb | ||
| dccp | ||
| decnet | ||
| dns_resolver | ||
| dsa | ||
| econet | ||
| ethernet | ||
| ieee802154 | ||
| ipv4 | ||
| ipv6 | ||
| ipx | ||
| irda | ||
| iucv | ||
| key | ||
| l2tp | ||
| lapb | ||
| llc | ||
| mac80211 | ||
| netfilter | ||
| netlabel | ||
| netlink | ||
| netrom | ||
| packet | ||
| phonet | ||
| rds | ||
| rfkill | ||
| rose | ||
| rxrpc | ||
| sched | ||
| sctp | ||
| sunrpc | ||
| tipc | ||
| unix | ||
| wanrouter | ||
| wimax | ||
| wireless | ||
| x25 | ||
| xfrm | ||
| compat.c | ||
| Kconfig | ||
| Makefile | ||
| nonet.c | ||
| socket.c | ||
| sysctl_net.c | ||
| TUNABLE | ||