4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jack Morgenstein jackm@dev.mellanox.co.il
[ Upstream commit d546b67cda015fb92bfee93d5dc0ceadb91deaee ]
spin_lock/unlock was used instead of spin_un/lock_irq in a procedure used in process space, on a spinlock which can be grabbed in an interrupt.
This caused the stack trace below to be displayed (on kernel 4.17.0-rc1 compiled with Lock Debugging enabled):
[ 154.661474] WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected [ 154.668909] 4.17.0-rc1-rdma_rc_mlx+ #3 Tainted: G I [ 154.675856] ----------------------------------------------------- [ 154.682706] modprobe/10159 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: [ 154.690254] 00000000f3b0e495 (&(&qp_table->lock)->rlock){+.+.}, at: mlx4_qp_remove+0x20/0x50 [mlx4_core] [ 154.700927] and this task is already holding: [ 154.707461] 0000000094373b5d (&(&cq->lock)->rlock/1){....}, at: destroy_qp_common+0x111/0x560 [mlx4_ib] [ 154.718028] which would create a new lock dependency: [ 154.723705] (&(&cq->lock)->rlock/1){....} -> (&(&qp_table->lock)->rlock){+.+.} [ 154.731922] but this new dependency connects a SOFTIRQ-irq-safe lock: [ 154.740798] (&(&cq->lock)->rlock){..-.} [ 154.740800] ... which became SOFTIRQ-irq-safe at: [ 154.752163] _raw_spin_lock_irqsave+0x3e/0x50 [ 154.757163] mlx4_ib_poll_cq+0x36/0x900 [mlx4_ib] [ 154.762554] ipoib_tx_poll+0x4a/0xf0 [ib_ipoib] ... to a SOFTIRQ-irq-unsafe lock: [ 154.815603] (&(&qp_table->lock)->rlock){+.+.} [ 154.815604] ... which became SOFTIRQ-irq-unsafe at: [ 154.827718] ... [ 154.827720] _raw_spin_lock+0x35/0x50 [ 154.833912] mlx4_qp_lookup+0x1e/0x50 [mlx4_core] [ 154.839302] mlx4_flow_attach+0x3f/0x3d0 [mlx4_core]
Since mlx4_qp_lookup() is called only in process space, we can simply replace the spin_un/lock calls with spin_un/lock_irq calls.
Fixes: 6dc06c08bef1 ("net/mlx4: Fix the check in attaching steering rules") Signed-off-by: Jack Morgenstein jackm@dev.mellanox.co.il Signed-off-by: Tariq Toukan tariqt@mellanox.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/mellanox/mlx4/qp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx4/qp.c +++ b/drivers/net/ethernet/mellanox/mlx4/qp.c @@ -386,11 +386,11 @@ struct mlx4_qp *mlx4_qp_lookup(struct ml struct mlx4_qp_table *qp_table = &mlx4_priv(dev)->qp_table; struct mlx4_qp *qp;
- spin_lock(&qp_table->lock); + spin_lock_irq(&qp_table->lock);
qp = __mlx4_qp_lookup(dev, qpn);
- spin_unlock(&qp_table->lock); + spin_unlock_irq(&qp_table->lock); return qp; }