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| author | Wilson Kok <wkok@cumulusnetworks.com> | 2015-06-05 09:52:57 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-06-08 00:24:54 +0200 |
| commit | 1d7c49037b12016e7056b9f2c990380e2187e766 (patch) | |
| tree | eddf23c9e9aa73e2e91447ea9ff8ed2f087d63eb | |
| parent | amd-xgbe: Use disable_irq_nosync from within timer function (diff) | |
| download | linux-1d7c49037b12016e7056b9f2c990380e2187e766.tar.xz linux-1d7c49037b12016e7056b9f2c990380e2187e766.zip | |
bridge: use _bh spinlock variant for br_fdb_update to avoid lockup
br_fdb_update() can be called in process context in the following way:
br_fdb_add() -> __br_fdb_add() -> br_fdb_update() (if NTF_USE flag is set)
so we need to use spin_lock_bh because there are softirq users of the
hash_lock. One easy way to reproduce this is to modify the bridge utility
to set NTF_USE, enable stp and then set maxageing to a low value so
br_fdb_cleanup() is called frequently and then just add new entries in
a loop. This happens because br_fdb_cleanup() is called from timer/softirq
context. These locks were _bh before commit f8ae737deea1
("[BRIDGE]: forwarding remove unneeded preempt and bh diasables")
and at the time that commit was correct because br_fdb_update() couldn't be
called from process context, but that changed after commit:
292d1398983f ("bridge: add NTF_USE support")
Signed-off-by: Wilson Kok <wkok@cumulusnetworks.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Fixes: 292d1398983f ("bridge: add NTF_USE support")
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/bridge/br_fdb.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c index e0670d7054f9..7eacc8ae9779 100644 --- a/net/bridge/br_fdb.c +++ b/net/bridge/br_fdb.c @@ -569,7 +569,7 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source, fdb_notify(br, fdb, RTM_NEWNEIGH); } } else { - spin_lock(&br->hash_lock); + spin_lock_bh(&br->hash_lock); if (likely(!fdb_find(head, addr, vid))) { fdb = fdb_create(head, source, addr, vid); if (fdb) { @@ -581,7 +581,7 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source, /* else we lose race and someone else inserts * it first, don't bother updating */ - spin_unlock(&br->hash_lock); + spin_unlock_bh(&br->hash_lock); } } |