From c3d34d5d9654ec9c2510f9341bfb1030b8f029d1 Mon Sep 17 00:00:00 2001 From: "John W. Linville" Date: Mon, 30 Aug 2010 17:36:40 -0400 Subject: [PATCH] wireless: register wiphy rfkill w/o holding cfg80211_mutex Otherwise lockdep complains... https://bugzilla.kernel.org/show_bug.cgi?id=17311 [ INFO: possible circular locking dependency detected ] 2.6.36-rc2-git4 #12 ------------------------------------------------------- kworker/0:3/3630 is trying to acquire lock: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x12/0x14 but task is already holding lock: (rfkill_global_mutex){+.+.+.}, at: [] rfkill_switch_all+0x24/0x49 [rfkill] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (rfkill_global_mutex){+.+.+.}: [] lock_acquire+0x120/0x15b [] __mutex_lock_common+0x54/0x52e [] mutex_lock_nested+0x34/0x39 [] rfkill_register+0x2b/0x29c [rfkill] [] wiphy_register+0x1ae/0x270 [cfg80211] [] ieee80211_register_hw+0x1b4/0x3cf [mac80211] [] iwl_ucode_callback+0x9e9/0xae3 [iwlagn] [] request_firmware_work_func+0x54/0x6f [] kthread+0x8c/0x94 [] kernel_thread_helper+0x4/0x10 -> #1 (cfg80211_mutex){+.+.+.}: [] lock_acquire+0x120/0x15b [] __mutex_lock_common+0x54/0x52e [] mutex_lock_nested+0x34/0x39 [] cfg80211_get_dev_from_ifindex+0x1b/0x7c [cfg80211] [] cfg80211_wext_giwscan+0x58/0x990 [cfg80211] [] ioctl_standard_iw_point+0x1a8/0x272 [] ioctl_standard_call+0x91/0xa7 [] T.723+0xbd/0x12c [] wext_handle_ioctl+0x31/0x6d [] dev_ioctl+0x63d/0x67a [] sock_ioctl+0x48/0x21d [] do_vfs_ioctl+0x4ba/0x509 [] sys_ioctl+0x51/0x74 [] system_call_fastpath+0x16/0x1b -> #0 (rtnl_mutex){+.+.+.}: [] __lock_acquire+0xa93/0xd9a [] lock_acquire+0x120/0x15b [] __mutex_lock_common+0x54/0x52e [] mutex_lock_nested+0x34/0x39 [] rtnl_lock+0x12/0x14 [] cfg80211_rfkill_set_block+0x1a/0x7b [cfg80211] [] rfkill_set_block+0x80/0xd5 [rfkill] [] __rfkill_switch_all+0x3f/0x6f [rfkill] [] rfkill_switch_all+0x38/0x49 [rfkill] [] rfkill_op_handler+0x105/0x136 [rfkill] [] process_one_work+0x248/0x403 [] worker_thread+0x139/0x214 [] kthread+0x8c/0x94 [] kernel_thread_helper+0x4/0x10 Signed-off-by: John W. Linville Acked-by: Johannes Berg --- net/wireless/core.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/net/wireless/core.c b/net/wireless/core.c index 541e2ff..d6d046b 100644 --- a/net/wireless/core.c +++ b/net/wireless/core.c @@ -475,12 +475,10 @@ int wiphy_register(struct wiphy *wiphy) mutex_lock(&cfg80211_mutex); res = device_add(&rdev->wiphy.dev); - if (res) - goto out_unlock; - - res = rfkill_register(rdev->rfkill); - if (res) - goto out_rm_dev; + if (res) { + mutex_unlock(&cfg80211_mutex); + return res; + } /* set up regulatory info */ wiphy_update_regulatory(wiphy, NL80211_REGDOM_SET_BY_CORE); @@ -509,13 +507,18 @@ int wiphy_register(struct wiphy *wiphy) cfg80211_debugfs_rdev_add(rdev); mutex_unlock(&cfg80211_mutex); + /* + * due to a locking dependency this has to be outside of the + * cfg80211_mutex lock + */ + res = rfkill_register(rdev->rfkill); + if (res) + goto out_rm_dev; + return 0; out_rm_dev: device_del(&rdev->wiphy.dev); - -out_unlock: - mutex_unlock(&cfg80211_mutex); return res; } EXPORT_SYMBOL(wiphy_register); -- 2.7.4