Re: wcn36xx: Introduce mutual exclusion of fw configuration
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From: Kalle Valo <hidden>
Date: 2017-08-08 11:08:50
Also in:
linux-wireless, lkml, stable
Bjorn Andersson [off-list ref] wrote:
As the association status changes the driver needs to configure the hardware. This is done based on information in the "sta" acquired by ieee80211_find_sta(), which requires the caller to ensure that the "sta" is valid while its being used; generally by entering an rcu read section. But the operations acting on the "sta" has to communicate with the firmware and may therefor sleep, resulting in the following report: [ 31.418190] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:238 [ 31.425919] in_atomic(): 0, irqs_disabled(): 0, pid: 34, name: kworker/u8:1 [ 31.434609] CPU: 0 PID: 34 Comm: kworker/u8:1 Tainted: G W 4.12.0-rc4-next-20170607+ #993 [ 31.441002] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT) [ 31.450380] Workqueue: phy0 ieee80211_iface_work [ 31.457226] Call trace: [ 31.461830] [<ffffff8008088c58>] dump_backtrace+0x0/0x260 [ 31.464004] [<ffffff8008088f7c>] show_stack+0x14/0x20 [ 31.469557] [<ffffff8008392e70>] dump_stack+0x98/0xb8 [ 31.474592] [<ffffff80080e4330>] ___might_sleep+0xf0/0x118 [ 31.479626] [<ffffff80080e43a8>] __might_sleep+0x50/0x88 [ 31.485010] [<ffffff80088ff9a4>] mutex_lock+0x24/0x60 [ 31.490479] [<ffffff8008595c38>] wcn36xx_smd_set_link_st+0x30/0x130 [ 31.495428] [<ffffff8008591ed8>] wcn36xx_bss_info_changed+0x148/0x448 [ 31.501504] [<ffffff80088ab3c4>] ieee80211_bss_info_change_notify+0xbc/0x118 [ 31.508102] [<ffffff80088f841c>] ieee80211_assoc_success+0x664/0x7f8 [ 31.515220] [<ffffff80088e13d4>] ieee80211_rx_mgmt_assoc_resp+0x144/0x2d8 [ 31.521555] [<ffffff80088e1e20>] ieee80211_sta_rx_queued_mgmt+0x190/0x698 [ 31.528239] [<ffffff80088bc44c>] ieee80211_iface_work+0x234/0x368 [ 31.535011] [<ffffff80080d81ac>] process_one_work+0x1cc/0x340 [ 31.541086] [<ffffff80080d8368>] worker_thread+0x48/0x430 [ 31.546814] [<ffffff80080de448>] kthread+0x108/0x138 [ 31.552195] [<ffffff8008082ec0>] ret_from_fork+0x10/0x50 In order to ensure that the "sta" remains alive (and consistent) for the duration of bss_info_changed() mutual exclusion has to be ensured with sta_remove(). This is done by introducing a mutex to cover firmware configuration changes, which is made to also ensure mutual exclusion between other operations changing the state or configuration of the firmware. With this we can drop the rcu read lock. Cc: stable@vger.kernel.org Signed-off-by: Bjorn Andersson <redacted> Signed-off-by: Kalle Valo <redacted>
Patch applied to ath-next branch of ath.git, thanks. 39efc7cc7ccf wcn36xx: Introduce mutual exclusion of fw configuration -- https://patchwork.kernel.org/patch/9877987/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches