[PATCH] mac80211: fix modprobe deadlock by not calling wep_init under rtnl_lock

From: Alan Jenkins
Date: Wed Apr 29 2009 - 06:41:24 EST


- ieee80211_wep_init(), which is called with rtnl_lock held, blocks in
request_module() [waiting for modprobe to load a crypto module].

- modprobe blocks in a call to flush_workqueue(), when it closes a TTY
[presumably when it exits].

- The workqueue item linkwatch_event() blocks on rtnl_lock.

There's no reason for wep_init() to be called with rtnl_lock held, so
just move it outside the critical section.

Signed-off-by: Alan Jenkins <alan-jenkins@xxxxxxxxxxxxxx>
---
net/mac80211/main.c | 19 +++++++++----------
1 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index fbcbed6..00968c2 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -909,6 +909,13 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
if (result < 0)
goto fail_sta_info;

+ result = ieee80211_wep_init(local);
+ if (result < 0) {
+ printk(KERN_DEBUG "%s: Failed to initialize wep: %d\n",
+ wiphy_name(local->hw.wiphy), result);
+ goto fail_wep;
+ }
+
rtnl_lock();
result = dev_alloc_name(local->mdev, local->mdev->name);
if (result < 0)
@@ -930,14 +937,6 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
goto fail_rate;
}

- result = ieee80211_wep_init(local);
-
- if (result < 0) {
- printk(KERN_DEBUG "%s: Failed to initialize wep: %d\n",
- wiphy_name(local->hw.wiphy), result);
- goto fail_wep;
- }
-
/* add one default STA interface if supported */
if (local->hw.wiphy->interface_modes & BIT(NL80211_IFTYPE_STATION)) {
result = ieee80211_if_add(local, "wlan%d", NULL,
@@ -967,13 +966,13 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)

return 0;

-fail_wep:
- rate_control_deinitialize(local);
fail_rate:
unregister_netdevice(local->mdev);
local->mdev = NULL;
fail_dev:
rtnl_unlock();
+ ieee80211_wep_free(local);
+fail_wep:
sta_info_stop(local);
fail_sta_info:
debugfs_hw_del(local);
--
1.5.4.3




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