From: Vladimir Oltean <vladimir.oltean@nxp.com> stable inclusion from stable-v5.10.104 commit 988f4f29cc44cb2c08d667901425dd7b093fe7cc bugzilla: https://gitee.com/openeuler/kernel/issues/I56XAC Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 10b6bb62ae1a49ee818fc479cf57b8900176773e ] Ido Schimmel points out that since commit 52cff74eef5d ("dcbnl : Disable software interrupts before taking dcb_lock"), the DCB API can be called by drivers from softirq context. One such in-tree example is the chelsio cxgb4 driver: dcb_rpl -> cxgb4_dcb_handle_fw_update -> dcb_ieee_setapp If the firmware for this driver happened to send an event which resulted in a call to dcb_ieee_setapp() at the exact same time as another DCB-enabled interface was unregistering on the same CPU, the softirq would deadlock, because the interrupted process was already holding the dcb_lock in dcbnl_flush_dev(). Fix this unlikely event by using spin_lock_bh() in dcbnl_flush_dev() as in the rest of the dcbnl code. Fixes: 91b0383fef06 ("net: dcb: flush lingering app table entries for unregistered devices") Reported-by: Ido Schimmel <idosch@idosch.org> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Link: https://lore.kernel.org/r/20220302193939.1368823-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yu Liao <liaoyu15@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- net/dcb/dcbnl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c index 799ff0efcc55..2535d3dfb92c 100644 --- a/net/dcb/dcbnl.c +++ b/net/dcb/dcbnl.c @@ -2067,7 +2067,7 @@ static void dcbnl_flush_dev(struct net_device *dev) { struct dcb_app_type *itr, *tmp; - spin_lock(&dcb_lock); + spin_lock_bh(&dcb_lock); list_for_each_entry_safe(itr, tmp, &dcb_app_list, list) { if (itr->ifindex == dev->ifindex) { @@ -2076,7 +2076,7 @@ static void dcbnl_flush_dev(struct net_device *dev) } } - spin_unlock(&dcb_lock); + spin_unlock_bh(&dcb_lock); } static int dcbnl_netdevice_event(struct notifier_block *nb, -- 2.20.1