| From 565b754075a05fb6a2a39b1860fa358b7ce9ef26 Mon Sep 17 00:00:00 2001 |
| From: Xin Long <lucien.xin@gmail.com> |
| Date: Tue, 4 Aug 2020 15:02:30 +0800 |
| Subject: [PATCH] net: thunderx: use spin_lock_bh in nicvf_set_rx_mode_task() |
| |
| commit bab9693a9a8c6dd19f670408ec1e78e12a320682 upstream. |
| |
| A dead lock was triggered on thunderx driver: |
| |
| CPU0 CPU1 |
| ---- ---- |
| [01] lock(&(&nic->rx_mode_wq_lock)->rlock); |
| [11] lock(&(&mc->mca_lock)->rlock); |
| [12] lock(&(&nic->rx_mode_wq_lock)->rlock); |
| [02] <Interrupt> lock(&(&mc->mca_lock)->rlock); |
| |
| The path for each is: |
| |
| [01] worker_thread() -> process_one_work() -> nicvf_set_rx_mode_task() |
| [02] mld_ifc_timer_expire() |
| [11] ipv6_add_dev() -> ipv6_dev_mc_inc() -> igmp6_group_added() -> |
| [12] dev_mc_add() -> __dev_set_rx_mode() -> nicvf_set_rx_mode() |
| |
| To fix it, it needs to disable bh on [1], so that the timer on [2] |
| wouldn't be triggered until rx_mode_wq_lock is released. So change |
| to use spin_lock_bh() instead of spin_lock(). |
| |
| Thanks to Paolo for helping with this. |
| |
| v1->v2: |
| - post to netdev. |
| |
| Reported-by: Rafael P. <rparrazo@redhat.com> |
| Tested-by: Dean Nelson <dnelson@redhat.com> |
| Fixes: 469998c861fa ("net: thunderx: prevent concurrent data re-writing by nicvf_set_rx_mode") |
| Signed-off-by: Xin Long <lucien.xin@gmail.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c |
| index 40a44dcb3d9b..f414f5651dbd 100644 |
| --- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c |
| +++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c |
| @@ -2047,11 +2047,11 @@ static void nicvf_set_rx_mode_task(struct work_struct *work_arg) |
| /* Save message data locally to prevent them from |
| * being overwritten by next ndo_set_rx_mode call(). |
| */ |
| - spin_lock(&nic->rx_mode_wq_lock); |
| + spin_lock_bh(&nic->rx_mode_wq_lock); |
| mode = vf_work->mode; |
| mc = vf_work->mc; |
| vf_work->mc = NULL; |
| - spin_unlock(&nic->rx_mode_wq_lock); |
| + spin_unlock_bh(&nic->rx_mode_wq_lock); |
| |
| __nicvf_set_rx_mode_task(mode, mc, nic); |
| } |
| -- |
| 2.27.0 |
| |