This is a note to let you know that I've just added the patch titled mwifiex: bring down link before deleting interface to the 5.12-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mwifiex-bring-down-link-before-deleting-interface.patch and it can be found in the queue-5.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 1f9482aa8d412b4ba06ce6ab8e333fb8ca29a06e Mon Sep 17 00:00:00 2001 From: Brian Norris <briannorris@xxxxxxxxxxxx> Date: Fri, 14 May 2021 19:42:27 -0700 Subject: mwifiex: bring down link before deleting interface From: Brian Norris <briannorris@xxxxxxxxxxxx> commit 1f9482aa8d412b4ba06ce6ab8e333fb8ca29a06e upstream. We can deadlock when rmmod'ing the driver or going through firmware reset, because the cfg80211_unregister_wdev() has to bring down the link for us, ... which then grab the same wiphy lock. nl80211_del_interface() already handles a very similar case, with a nice description: /* * We hold RTNL, so this is safe, without RTNL opencount cannot * reach 0, and thus the rdev cannot be deleted. * * We need to do it for the dev_close(), since that will call * the netdev notifiers, and we need to acquire the mutex there * but don't know if we get there from here or from some other * place (e.g. "ip link set ... down"). */ mutex_unlock(&rdev->wiphy.mtx); ... Do similarly for mwifiex teardown, by ensuring we bring the link down first. Sample deadlock trace: [ 247.103516] INFO: task rmmod:2119 blocked for more than 123 seconds. [ 247.110630] Not tainted 5.12.4 #5 [ 247.115796] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 247.124557] task:rmmod state:D stack: 0 pid: 2119 ppid: 2114 flags:0x00400208 [ 247.133905] Call trace: [ 247.136644] __switch_to+0x130/0x170 [ 247.140643] __schedule+0x714/0xa0c [ 247.144548] schedule_preempt_disabled+0x88/0xf4 [ 247.149714] __mutex_lock_common+0x43c/0x750 [ 247.154496] mutex_lock_nested+0x5c/0x68 [ 247.158884] cfg80211_netdev_notifier_call+0x280/0x4e0 [cfg80211] [ 247.165769] raw_notifier_call_chain+0x4c/0x78 [ 247.170742] call_netdevice_notifiers_info+0x68/0xa4 [ 247.176305] __dev_close_many+0x7c/0x138 [ 247.180693] dev_close_many+0x7c/0x10c [ 247.184893] unregister_netdevice_many+0xfc/0x654 [ 247.190158] unregister_netdevice_queue+0xb4/0xe0 [ 247.195424] _cfg80211_unregister_wdev+0xa4/0x204 [cfg80211] [ 247.201816] cfg80211_unregister_wdev+0x20/0x2c [cfg80211] [ 247.208016] mwifiex_del_virtual_intf+0xc8/0x188 [mwifiex] [ 247.214174] mwifiex_uninit_sw+0x158/0x1b0 [mwifiex] [ 247.219747] mwifiex_remove_card+0x38/0xa0 [mwifiex] [ 247.225316] mwifiex_pcie_remove+0xd0/0xe0 [mwifiex_pcie] [ 247.231451] pci_device_remove+0x50/0xe0 [ 247.235849] device_release_driver_internal+0x110/0x1b0 [ 247.241701] driver_detach+0x5c/0x9c [ 247.245704] bus_remove_driver+0x84/0xb8 [ 247.250095] driver_unregister+0x3c/0x60 [ 247.254486] pci_unregister_driver+0x2c/0x90 [ 247.259267] cleanup_module+0x18/0xcdc [mwifiex_pcie] Fixes: a05829a7222e ("cfg80211: avoid holding the RTNL when calling the driver") Cc: stable@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/linux-wireless/98392296-40ee-6300-369c-32e16cff3725@xxxxxxxxx/ Link: https://lore.kernel.org/linux-wireless/ab4d00ce52f32bd8e45ad0448a44737e@xxxxxxxxx/ Reported-by: Maximilian Luz <luzmaximilian@xxxxxxxxx> Reported-by: dave@xxxxxxxxx Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx> Tested-by: Maximilian Luz <luzmaximilian@xxxxxxxxx> Tested-by: Dave Olsthoorn <dave@xxxxxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210515024227.2159311-1-briannorris@xxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/wireless/marvell/mwifiex/main.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) --- a/drivers/net/wireless/marvell/mwifiex/main.c +++ b/drivers/net/wireless/marvell/mwifiex/main.c @@ -1445,11 +1445,18 @@ static void mwifiex_uninit_sw(struct mwi if (!priv) continue; rtnl_lock(); - wiphy_lock(adapter->wiphy); if (priv->netdev && - priv->wdev.iftype != NL80211_IFTYPE_UNSPECIFIED) + priv->wdev.iftype != NL80211_IFTYPE_UNSPECIFIED) { + /* + * Close the netdev now, because if we do it later, the + * netdev notifiers will need to acquire the wiphy lock + * again --> deadlock. + */ + dev_close(priv->wdev.netdev); + wiphy_lock(adapter->wiphy); mwifiex_del_virtual_intf(adapter->wiphy, &priv->wdev); - wiphy_unlock(adapter->wiphy); + wiphy_unlock(adapter->wiphy); + } rtnl_unlock(); } Patches currently in stable-queue which might be from briannorris@xxxxxxxxxxxx are queue-5.12/mwifiex-bring-down-link-before-deleting-interface.patch