]> git.proxmox.com Git - mirror_ubuntu-focal-kernel.git/commitdiff
net: dcb: disable softirqs in dcbnl_flush_dev()
authorVladimir Oltean <vladimir.oltean@nxp.com>
Wed, 2 Mar 2022 19:39:39 +0000 (21:39 +0200)
committerStefan Bader <stefan.bader@canonical.com>
Fri, 20 May 2022 13:17:34 +0000 (15:17 +0200)
BugLink: https://bugs.launchpad.net/bugs/1969239
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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
net/dcb/dcbnl.c

index d313752ba05c55aaa0ddb1a28fe43ab9735b584d..b53d5e1d026fe6ae2590582444038e1a17cf0f65 100644 (file)
@@ -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,