Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.7 71/79] net: thunderx: use spin_lock_bh in nicvf_set_rx_mode_task() | Date | Mon, 10 Aug 2020 17:21:30 +0200 |
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From: Xin Long <lucien.xin@gmail.com>
[ Upstream commit bab9693a9a8c6dd19f670408ec1e78e12a320682 ]
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/net/ethernet/cavium/thunder/nicvf_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c +++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c @@ -2041,11 +2041,11 @@ static void nicvf_set_rx_mode_task(struc /* 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); }
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