diff options
| author | Wilson Kok <wkok@cumulusnetworks.com> | 2015-06-05 10:52:57 +0300 |
|---|---|---|
| committer | Zefan Li <lizefan@huawei.com> | 2015-09-18 04:20:45 +0300 |
| commit | 0b6afbdd165890743b64c57c07cbc4e6e3174b35 (patch) | |
| tree | dc01ced7c4f20a848e2a5ee93bd128f3d82755fe /net | |
| parent | a5c75be0e779d38c970b4a2129c238a5bab0dad4 (diff) | |
| download | linux-0b6afbdd165890743b64c57c07cbc4e6e3174b35.tar.xz | |
bridge: use _bh spinlock variant for br_fdb_update to avoid lockup
commit 1d7c49037b12016e7056b9f2c990380e2187e766 upstream.
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>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
Diffstat (limited to '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 5ba0c844d508..b5597bb37e7a 100644 --- a/net/bridge/br_fdb.c +++ b/net/bridge/br_fdb.c @@ -440,7 +440,7 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source, fdb->updated = jiffies; } } else { - spin_lock(&br->hash_lock); + spin_lock_bh(&br->hash_lock); if (likely(!fdb_find(head, addr))) { fdb = fdb_create(head, source, addr); if (fdb) @@ -449,7 +449,7 @@ 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); } } |