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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Moni Shoua <monis@mellanox.com>,
	Leon Romanovsky <leonro@mellanox.com>,
	Saeed Mahameed <saeedm@mellanox.com>,
	Sasha Levin <sashal@kernel.org>,
	netdev@vger.kernel.org, linux-rdma@vger.kernel.org
Subject: [PATCH AUTOSEL 4.19 133/671] net/mlx5: Take lock with IRQs disabled to avoid deadlock
Date: Thu, 16 Jan 2020 11:50:42 -0500
Message-ID: <20200116165940.10720-16-sashal@kernel.org> (raw)
In-Reply-To: <20200116165940.10720-1-sashal@kernel.org>

From: Moni Shoua <monis@mellanox.com>

[ Upstream commit 33814e5d127e21f53b52e17b0722c1b57d4f4d29 ]

The lock in qp_table might be taken from process context or from
interrupt context. This may lead to a deadlock unless it is taken with
IRQs disabled.

Discovered by lockdep

================================
WARNING: inconsistent lock state
4.20.0-rc6
--------------------------------
inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W}

python/12572 [HC1[1]:SC0[0]:HE0:SE1] takes:
00000000052a4df4 (&(&table->lock)->rlock#2){?.+.}, /0x50 [mlx5_core]
{HARDIRQ-ON-W} state was registered at:
  _raw_spin_lock+0x33/0x70
  mlx5_get_rsc+0x1a/0x50 [mlx5_core]
  mlx5_ib_eqe_pf_action+0x493/0x1be0 [mlx5_ib]
  process_one_work+0x90c/0x1820
  worker_thread+0x87/0xbb0
  kthread+0x320/0x3e0
  ret_from_fork+0x24/0x30
irq event stamp: 103928
hardirqs last  enabled at (103927): [] nk+0x1a/0x1c
hardirqs last disabled at (103928): [] unk+0x1a/0x1c
softirqs last  enabled at (103924): [] tcp_sendmsg+0x31/0x40
softirqs last disabled at (103922): [] 80

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&table->lock)->rlock#2);

    lock(&(&table->lock)->rlock#2);

 *** DEADLOCK ***

Fixes: 032080ab43ac ("IB/mlx5: Lock QP during page fault handling")
Signed-off-by: Moni Shoua <monis@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/mellanox/mlx5/core/qp.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/qp.c b/drivers/net/ethernet/mellanox/mlx5/core/qp.c
index f33707ce8b6b..479ac21cdbc6 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/qp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/qp.c
@@ -44,14 +44,15 @@ static struct mlx5_core_rsc_common *mlx5_get_rsc(struct mlx5_core_dev *dev,
 {
 	struct mlx5_qp_table *table = &dev->priv.qp_table;
 	struct mlx5_core_rsc_common *common;
+	unsigned long flags;
 
-	spin_lock(&table->lock);
+	spin_lock_irqsave(&table->lock, flags);
 
 	common = radix_tree_lookup(&table->tree, rsn);
 	if (common)
 		atomic_inc(&common->refcount);
 
-	spin_unlock(&table->lock);
+	spin_unlock_irqrestore(&table->lock, flags);
 
 	if (!common) {
 		mlx5_core_warn(dev, "Async event for bogus resource 0x%x\n",
-- 
2.20.1


  parent reply index

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200116165940.10720-1-sashal@kernel.org>
2020-01-16 16:50 ` [PATCH AUTOSEL 4.19 123/671] IB/iser: Pass the correct number of entries for dma mapped SGL Sasha Levin
2020-01-16 16:50 ` [PATCH AUTOSEL 4.19 126/671] IB/mlx5: Don't override existing ip_protocol Sasha Levin
2020-01-16 16:50 ` Sasha Levin [this message]
2020-01-16 16:51 ` [PATCH AUTOSEL 4.19 167/671] iw_cxgb4: use tos when importing the endpoint Sasha Levin
2020-01-16 16:51 ` [PATCH AUTOSEL 4.19 168/671] iw_cxgb4: use tos when finding ipv6 routes Sasha Levin
2020-01-16 16:51 ` [PATCH AUTOSEL 4.19 178/671] RDMA/mlx5: Fix memory leak in case we fail to add an IB device Sasha Levin
2020-01-16 16:51 ` [PATCH AUTOSEL 4.19 201/671] net/mlx5: Delete unused FPGA QPN variable Sasha Levin
2020-01-16 16:52 ` [PATCH AUTOSEL 4.19 243/671] net/mlx5: Fix multiple updates of steering rules in parallel Sasha Levin
2020-01-16 16:52 ` [PATCH AUTOSEL 4.19 244/671] net/mlx5e: IPoIB, Fix RX checksum statistics update Sasha Levin

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