[PATCH 5.15 053/135] net/mlx5: Fix deadlock in sync reset flow

Greg Kroah-Hartman
2022-05-10T14:01:15Z

From: Moshe Shemesh <moshe@nvidia.com>

commit cb7786a76ea39f394f0a059787fe24fa8e340fb6 upstream.

The sync reset flow can lead to the following deadlock when
poll_sync_reset() is called by timer softirq and waiting on
del_timer_sync() for the same timer. Fix that by moving the part of the
flow that waits for the timer to reset_reload_work.

It fixes the following kernel Trace:
RIP: 0010:del_timer_sync+0x32/0x40
...
Call Trace:
<IRQ>
mlx5_sync_reset_clear_reset_requested+0x26/0x50 [mlx5_core]
poll_sync_reset.cold+0x36/0x52 [mlx5_core]
call_timer_fn+0x32/0x130
__run_timers.part.0+0x180/0x280
? tick_sched_handle+0x33/0x60
? tick_sched_timer+0x3d/0x80
? ktime_get+0x3e/0xa0
run_timer_softirq+0x2a/0x50
__do_softirq+0xe1/0x2d6
? hrtimer_interrupt+0x136/0x220
irq_exit+0xae/0xb0
smp_apic_timer_interrupt+0x7b/0x140
apic_timer_interrupt+0xf/0x20
</IRQ>

Fixes: 3c5193a87b0f ("net/mlx5: Use del_timer_sync in fw reset flow of halting poll")
Signed-off-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Maher Sanalla <msanalla@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c | 34 ++++++++++-----------
1 file changed, 17 insertions(+), 17 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
@@ -111,22 +111,6 @@ static void mlx5_fw_reset_complete_reloa
}
}

-static void mlx5_sync_reset_reload_work(struct work_struct *work)
-{
- struct mlx5_fw_reset *fw_reset = container_of(work, struct mlx5_fw_reset,
- reset_reload_work);
- struct mlx5_core_dev *dev = fw_reset->dev;
- int err;
-
- mlx5_enter_error_state(dev, true);
- mlx5_unload_one(dev);
- err = mlx5_health_wait_pci_up(dev);
- if (err)
- mlx5_core_err(dev, "reset reload flow aborted, PCI reads still not working\n");
- fw_reset->ret = err;
- mlx5_fw_reset_complete_reload(dev);
-}
-
static void mlx5_stop_sync_reset_poll(struct mlx5_core_dev *dev)
{
struct mlx5_fw_reset *fw_reset = dev->priv.fw_reset;
@@ -149,6 +133,23 @@ static int mlx5_sync_reset_clear_reset_r
return 0;
}

+static void mlx5_sync_reset_reload_work(struct work_struct *work)
+{
+ struct mlx5_fw_reset *fw_reset = container_of(work, struct mlx5_fw_reset,
+ reset_reload_work);
+ struct mlx5_core_dev *dev = fw_reset->dev;
+ int err;
+
+ mlx5_sync_reset_clear_reset_requested(dev, false);
+ mlx5_enter_error_state(dev, true);
+ mlx5_unload_one(dev);
+ err = mlx5_health_wait_pci_up(dev);
+ if (err)
+ mlx5_core_err(dev, "reset reload flow aborted, PCI reads still not working\n");
+ fw_reset->ret = err;
+ mlx5_fw_reset_complete_reload(dev);
+}
+
#define MLX5_RESET_POLL_INTERVAL (HZ / 10)
static void poll_sync_reset(struct timer_list *t)
{
@@ -163,7 +164,6 @@ static void poll_sync_reset(struct timer

if (fatal_error) {
mlx5_core_warn(dev, "Got Device Reset\n");
- mlx5_sync_reset_clear_reset_requested(dev, false);
queue_work(fw_reset->wq, &fw_reset->reset_reload_work);
return;
}