Return-path: Received: from mail2.candelatech.com ([208.74.158.173]:48181 "EHLO mail2.candelatech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754088AbcDAVMV (ORCPT ); Fri, 1 Apr 2016 17:12:21 -0400 From: greearb@candelatech.com To: ath10k@lists.infradead.org Cc: linux-wireless@vger.kernel.org, Ben Greear Subject: [PATCH v2 5/5] ath10k: Fix deadlock when peer cannot be created. Date: Fri, 1 Apr 2016 14:12:12 -0700 Message-Id: <1459545132-11295-5-git-send-email-greearb@candelatech.com> (sfid-20160401_231229_823458_DF180178) In-Reply-To: <1459545132-11295-1-git-send-email-greearb@candelatech.com> References: <1459545132-11295-1-git-send-email-greearb@candelatech.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: From: Ben Greear We must not attempt to send WMI packets while holding the data-lock, as it may deadlock: BUG: sleeping function called from invalid context at drivers/net/wireless/ath/ath10k/wmi.c:1824 in_atomic(): 1, irqs_disabled(): 0, pid: 2878, name: wpa_supplicant ============================================= [ INFO: possible recursive locking detected ] 4.4.6+ #21 Tainted: G W O --------------------------------------------- wpa_supplicant/2878 is trying to acquire lock: (&(&ar->data_lock)->rlock){+.-...}, at: [] ath10k_wmi_tx_beacons_iter+0x26/0x11a [ath10k_core] but task is already holding lock: (&(&ar->data_lock)->rlock){+.-...}, at: [] ath10k_peer_create+0x122/0x1ae [ath10k_core] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&ar->data_lock)->rlock); lock(&(&ar->data_lock)->rlock); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by wpa_supplicant/2878: #0: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x12/0x14 #1: (&ar->conf_mutex){+.+.+.}, at: [] ath10k_add_interface+0x3b/0xbda [ath10k_core] #2: (&(&ar->data_lock)->rlock){+.-...}, at: [] ath10k_peer_create+0x122/0x1ae [ath10k_core] #3: (rcu_read_lock){......}, at: [] rcu_read_lock+0x0/0x66 [mac80211] stack backtrace: CPU: 3 PID: 2878 Comm: wpa_supplicant Tainted: G W O 4.4.6+ #21 Hardware name: To be filled by O.E.M. To be filled by O.E.M./ChiefRiver, BIOS 4.6.5 06/07/2013 0000000000000000 ffff8801fcadf8f0 ffffffff8137086d ffffffff82681720 ffffffff82681720 ffff8801fcadf9b0 ffffffff8112e3be ffff8801fcadf920 0000000100000000 ffffffff82681720 ffffffffa0721500 ffff8801fcb8d348 Call Trace: [] dump_stack+0x81/0xb6 [] __lock_acquire+0xc5b/0xde7 [] ? ath10k_wmi_tx_beacons_iter+0x15/0x11a [ath10k_core] [] ? mark_lock+0x24/0x201 [] lock_acquire+0x132/0x1cb [] ? lock_acquire+0x132/0x1cb [] ? ath10k_wmi_tx_beacons_iter+0x26/0x11a [ath10k_core] [] ? ath10k_wmi_cmd_send_nowait+0x1ce/0x1ce [ath10k_core] [] _raw_spin_lock_bh+0x31/0x40 [] ? ath10k_wmi_tx_beacons_iter+0x26/0x11a [ath10k_core] [] ath10k_wmi_tx_beacons_iter+0x26/0x11a [ath10k_core] [] ? ath10k_wmi_cmd_send_nowait+0x1ce/0x1ce [ath10k_core] [] __iterate_interfaces+0x9d/0x13d [mac80211] [] ieee80211_iterate_active_interfaces_atomic+0x32/0x3e [mac80211] [] ? ath10k_wmi_cmd_send_nowait+0x1ce/0x1ce [ath10k_core] [] ath10k_wmi_tx_beacons_nowait.isra.13+0x14/0x16 [ath10k_core] [] ath10k_wmi_cmd_send+0x71/0x242 [ath10k_core] [] ath10k_wmi_peer_delete+0x3f/0x42 [ath10k_core] [] ath10k_peer_create+0x15e/0x1ae [ath10k_core] [] ath10k_add_interface+0x70d/0xbda [ath10k_core] [] drv_add_interface+0x123/0x1a5 [mac80211] [] ieee80211_do_open+0x351/0x667 [mac80211] [] ieee80211_open+0x49/0x4c [mac80211] [] __dev_open+0x88/0xde [] __dev_change_flags+0xa4/0x13a [] dev_change_flags+0x1f/0x54 [] devinet_ioctl+0x2b9/0x5c9 [] ? copy_to_user+0x32/0x38 [] inet_ioctl+0x81/0x9d [] ? inet_ioctl+0x81/0x9d [] sock_do_ioctl+0x20/0x3d [] sock_ioctl+0x222/0x22e [] do_vfs_ioctl+0x453/0x4d7 [] ? __sys_recvmsg+0x4c/0x5b [] ? __fget_light+0x48/0x6c [] SyS_ioctl+0x52/0x74 [] entry_SYSCALL_64_fastpath+0x16/0x7a Signed-off-by: Ben Greear --- drivers/net/wireless/ath/ath10k/mac.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c index 020dd25..be8345c 100644 --- a/drivers/net/wireless/ath/ath10k/mac.c +++ b/drivers/net/wireless/ath/ath10k/mac.c @@ -700,10 +700,10 @@ static int ath10k_peer_create(struct ath10k *ar, peer = ath10k_peer_find(ar, vdev_id, addr); if (!peer) { + spin_unlock_bh(&ar->data_lock); ath10k_warn(ar, "failed to find peer %pM on vdev %i after creation\n", addr, vdev_id); ath10k_wmi_peer_delete(ar, vdev_id, addr); - spin_unlock_bh(&ar->data_lock); return -ENOENT; } -- 2.4.3