| Message ID | 9809b6b99bf5ba2dc8d1440c7d4fc93d04a7504a.1596524550.git.lucien.xin@gmail.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | bab9693a9a8c6dd19f670408ec1e78e12a320682 |
| Headers | show |
| Series | [PATCHv2,net] net: thunderx: use spin_lock_bh in nicvf_set_rx_mode_task() | expand |
From: Xin Long <lucien.xin@gmail.com> Date: Tue, 4 Aug 2020 15:02:30 +0800 > 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> Applied and queued up for -stable, thank you.
diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c index 2ba0ce1..a82c708 100644 --- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c +++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c @@ -2042,11 +2042,11 @@ 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); }
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> --- drivers/net/ethernet/cavium/thunder/nicvf_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)