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Date: Sun, 9 Mar 2014 21:06:51 +0100 From: Emil Goode <emilgoode@...il.com> To: Brett Rudley <brudley@...adcom.com>, Arend van Spriel <arend@...adcom.com>, "Franky (Zhenhui) Lin" <frankyl@...adcom.com>, Hante Meuleman <meuleman@...adcom.com>, "John W. Linville" <linville@...driver.com>, Hauke Mehrtens <hauke@...ke-m.de>, Johannes Berg <johannes.berg@...el.com>, "Luis R. Rodriguez" <mcgrof@...not-panic.com> Cc: linux-wireless@...r.kernel.org, brcm80211-dev-list@...adcom.com, netdev@...r.kernel.org, linux-kernel@...r.kernel.org, Emil Goode <emilgoode@...il.com> Subject: [PATCH 1/2] brcmsmac: fix deadlock on missing firmware When brcm80211 firmware is not installed networking hangs. A deadlock happens because we call ieee80211_unregister_hw() from the .start callback of struct ieee80211_ops. When .start is called we are under rtnl lock and ieee80211_unregister_hw() tries to take it again. Function call stack: dev_change_flags() __dev_change_flags() __dev_open() ASSERT_RTNL() <-- Assert rtnl lock ops->ndo_open() .ndo_open = ieee80211_open, ieee80211_open() ieee80211_do_open() drv_start() local->ops->start() .start = brcms_ops_start, brcms_ops_start() brcms_remove() ieee80211_unregister_hw() rtnl_lock() <-- Here we deadlock Introduced by: commit 25b5632fb35ca61b8ae3eee235edcdc2883f7a5e ("brcmsmac: request firmware in .start() callback") This patch fixes the bug by removing the call to brcms_remove() and moves the brcms_request_fw() call to the top of the .start callback to not initiate anything unless firmware is installed. Signed-off-by: Emil Goode <emilgoode@...il.com> --- drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c b/drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c index 925034b..93598cd 100644 --- a/drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c +++ b/drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c @@ -426,6 +426,12 @@ static int brcms_ops_start(struct ieee80211_hw *hw) bool blocked; int err; + if (!wl->ucode.bcm43xx_bomminor) { + err = brcms_request_fw(wl, wl->wlc->hw->d11core); + if (err) + return -ENOENT; + } + ieee80211_wake_queues(hw); spin_lock_bh(&wl->lock); blocked = brcms_rfkill_set_hw_state(wl); @@ -433,14 +439,6 @@ static int brcms_ops_start(struct ieee80211_hw *hw) if (!blocked) wiphy_rfkill_stop_polling(wl->pub->ieee_hw->wiphy); - if (!wl->ucode.bcm43xx_bomminor) { - err = brcms_request_fw(wl, wl->wlc->hw->d11core); - if (err) { - brcms_remove(wl->wlc->hw->d11core); - return -ENOENT; - } - } - spin_lock_bh(&wl->lock); /* avoid acknowledging frames before a non-monitor device is added */ wl->mute_tx = true; -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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