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| author | Vladimir Oltean <vladimir.oltean@nxp.com> | 2022-03-02 21:39:39 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-03-03 08:01:55 -0800 |
| commit | 10b6bb62ae1a49ee818fc479cf57b8900176773e (patch) | |
| tree | 805e60ea72baec1086592d580c33cb6b3ee99b99 /net/dcb | |
| parent | 8ccffe9ac3239e549beaa0a9d5e1a1eac94e866c (diff) | |
| download | lwn-10b6bb62ae1a49ee818fc479cf57b8900176773e.tar.gz lwn-10b6bb62ae1a49ee818fc479cf57b8900176773e.zip | |
net: dcb: disable softirqs in dcbnl_flush_dev()
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>
Diffstat (limited to 'net/dcb')
| -rw-r--r-- | net/dcb/dcbnl.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c index 36c91273daac..dc4fb699b56c 100644 --- a/net/dcb/dcbnl.c +++ b/net/dcb/dcbnl.c @@ -2077,7 +2077,7 @@ 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) { @@ -2086,7 +2086,7 @@ 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, |