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authorMoni Shoua <monis@mellanox.com>2018-12-26 18:21:21 +0100
committerSaeed Mahameed <saeedm@mellanox.com>2019-01-25 21:00:28 +0100
commit33814e5d127e21f53b52e17b0722c1b57d4f4d29 (patch)
tree9fdb2f476fc7ae022cf262632bb079e224fbeaea
parentnet/mlx5e: Fix wrong private flag usage causing checksum disable (diff)
downloadlinux-33814e5d127e21f53b52e17b0722c1b57d4f4d29.tar.xz
linux-33814e5d127e21f53b52e17b0722c1b57d4f4d29.zip
net/mlx5: Take lock with IRQs disabled to avoid deadlock
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>
-rw-r--r--drivers/net/ethernet/mellanox/mlx5/core/qp.c5
1 files 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 388f205a497f..370ca94b6775 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_qp_table *table, u32 rsn)
{
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);
return common;
}