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 5f091c6ea049d..b92d5690287b5 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",