| From 10b6bb62ae1a49ee818fc479cf57b8900176773e Mon Sep 17 00:00:00 2001 |
| From: Vladimir Oltean <vladimir.oltean@nxp.com> |
| Date: Wed, 2 Mar 2022 21:39:39 +0200 |
| Subject: net: dcb: disable softirqs in dcbnl_flush_dev() |
| |
| From: Vladimir Oltean <vladimir.oltean@nxp.com> |
| |
| commit 10b6bb62ae1a49ee818fc479cf57b8900176773e upstream. |
| |
| 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/dcb/dcbnl.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/net/dcb/dcbnl.c |
| +++ b/net/dcb/dcbnl.c |
| @@ -2067,7 +2067,7 @@ static void dcbnl_flush_dev(struct net_d |
| { |
| 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_d |
| } |
| } |
| |
| - spin_unlock(&dcb_lock); |
| + spin_unlock_bh(&dcb_lock); |
| } |
| |
| static int dcbnl_netdevice_event(struct notifier_block *nb, |
