From 10be6b48fd870f1076f746d614deed6b9d21ce2a Mon Sep 17 00:00:00 2001 From: Hariprasad Shenai Date: Fri, 21 Nov 2014 09:36:35 -0600 Subject: [PATCH] RDMA/cxgb4: Fix locking issue in process_mpa_request Fix the following lockdep report: ============================================= [ INFO: possible recursive locking detected ] 3.17.0+ #3 Tainted: G E --------------------------------------------- kworker/u64:3/299 is trying to acquire lock: (&epc->mutex){+.+.+.}, at: [] process_mpa_request+0x1aa/0x3e0 [iw_cxgb4] but task is already holding lock: (&epc->mutex){+.+.+.}, at: [] rx_data+0x9e/0x1f0 [iw_cxgb4] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&epc->mutex); lock(&epc->mutex); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by kworker/u64:3/299: #0: ("%s""iw_cxgb4"){.+.+.+}, at: [] process_one_work+0x13d/0x4d0 #1: (skb_work){+.+.+.}, at: [] process_one_work+0x13d/0x4d0 #2: (&epc->mutex){+.+.+.}, at: [] rx_data+0x9e/0x1f0 [iw_cxgb4] stack backtrace: CPU: 2 PID: 299 Comm: kworker/u64:3 Tainted: G E 3.17.0+ #3 Hardware name: Dell Inc. PowerEdge T110/0X744K, BIOS 1.2.1 01/28/2010 Workqueue: iw_cxgb4 process_work [iw_cxgb4] ffff8800b91593d0 ffff8800b8a2f9f8 ffffffff815df107 0000000000000001 ffff8800b9158750 ffff8800b8a2fa28 ffffffff8109f0e2 ffff8800bb768a00 ffff8800b91593d0 ffff8800b9158750 0000000000000000 ffff8800b8a2fa88 Call Trace: [] dump_stack+0x49/0x62 [] print_deadlock_bug+0xf2/0x100 [] validate_chain+0x454/0x700 [] __lock_acquire+0x3c4/0x580 [] ? process_mpa_request+0x1aa/0x3e0 [iw_cxgb4] [] lock_acquire+0x9c/0x110 [] ? process_mpa_request+0x1aa/0x3e0 [iw_cxgb4] [] mutex_lock_nested+0x4b/0x360 [] ? process_mpa_request+0x1aa/0x3e0 [iw_cxgb4] [] ? del_timer_sync+0xaa/0xd0 [] ? try_to_del_timer_sync+0x70/0x70 [] process_mpa_request+0x1aa/0x3e0 [iw_cxgb4] [] ? update_rx_credits+0xec/0x140 [iw_cxgb4] [] rx_data+0xd1/0x1f0 [iw_cxgb4] [] ? mark_held_locks+0x73/0xa0 [] ? _raw_spin_unlock_irqrestore+0x40/0x70 [] ? trace_hardirqs_on_caller+0xfd/0x1c0 [] ? trace_hardirqs_on+0xd/0x10 [] process_work+0x51/0x80 [iw_cxgb4] [] process_one_work+0x1b8/0x4d0 [] ? process_one_work+0x13d/0x4d0 [] worker_thread+0x120/0x3c0 [] ? process_one_work+0x4d0/0x4d0 [] kthread+0xde/0x100 [] ? _raw_spin_unlock_irq+0x30/0x40 [] ? __init_kthread_worker+0x70/0x70 [] ret_from_fork+0x7c/0xb0 [] ? __init_kthread_worker+0x70/0x70 Based on original work by Steve Wise . Signed-off-by: Steve Wise Signed-off-by: Hariprasad Shenai Signed-off-by: Roland Dreier --- drivers/infiniband/hw/cxgb4/cm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c index 4b8c6116c058..00756210b7a8 100644 --- a/drivers/infiniband/hw/cxgb4/cm.c +++ b/drivers/infiniband/hw/cxgb4/cm.c @@ -1640,7 +1640,8 @@ static void process_mpa_request(struct c4iw_ep *ep, struct sk_buff *skb) __state_set(&ep->com, MPA_REQ_RCVD); /* drive upcall */ - mutex_lock(&ep->parent_ep->com.mutex); + mutex_lock_nested(&ep->parent_ep->com.mutex, + SINGLE_DEPTH_NESTING); if (ep->parent_ep->com.state != DEAD) { if (connect_request_upcall(ep)) abort_connection(ep, skb, GFP_KERNEL); -- 2.20.1