diff options
| author | Ido Schimmel <idosch@mellanox.com> | 2020-07-29 11:34:36 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-07-29 12:04:54 -0700 |
| commit | b5141915b5aec3b29a63db869229e3741ebce258 (patch) | |
| tree | 0fb3c7d45c1714d6ccaed469fd018e1d38043e64 | |
| parent | 1ed06dbc213e1408ab60faa3ac0c0855a3ddc52d (diff) | |
| download | linux-b5141915b5aec3b29a63db869229e3741ebce258.tar.bz2 | |
vxlan: Ensure FDB dump is performed under RCU
The commit cited below removed the RCU read-side critical section from
rtnl_fdb_dump() which means that the ndo_fdb_dump() callback is invoked
without RCU protection.
This results in the following warning [1] in the VXLAN driver, which
relied on the callback being invoked from an RCU read-side critical
section.
Fix this by calling rcu_read_lock() in the VXLAN driver, as already done
in the bridge driver.
[1]
WARNING: suspicious RCU usage
5.8.0-rc4-custom-01521-g481007553ce6 #29 Not tainted
-----------------------------
drivers/net/vxlan.c:1379 RCU-list traversed in non-reader section!!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
1 lock held by bridge/166:
#0: ffffffff85a27850 (rtnl_mutex){+.+.}-{3:3}, at: netlink_dump+0xea/0x1090
stack backtrace:
CPU: 1 PID: 166 Comm: bridge Not tainted 5.8.0-rc4-custom-01521-g481007553ce6 #29
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-2.fc32 04/01/2014
Call Trace:
dump_stack+0x100/0x184
lockdep_rcu_suspicious+0x153/0x15d
vxlan_fdb_dump+0x51e/0x6d0
rtnl_fdb_dump+0x4dc/0xad0
netlink_dump+0x540/0x1090
__netlink_dump_start+0x695/0x950
rtnetlink_rcv_msg+0x802/0xbd0
netlink_rcv_skb+0x17a/0x480
rtnetlink_rcv+0x22/0x30
netlink_unicast+0x5ae/0x890
netlink_sendmsg+0x98a/0xf40
__sys_sendto+0x279/0x3b0
__x64_sys_sendto+0xe6/0x1a0
do_syscall_64+0x54/0xa0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fe14fa2ade0
Code: Bad RIP value.
RSP: 002b:00007fff75bb5b88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00005614b1ba0020 RCX: 00007fe14fa2ade0
RDX: 000000000000011c RSI: 00007fff75bb5b90 RDI: 0000000000000003
RBP: 00007fff75bb5b90 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00005614b1b89160
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Fixes: 5e6d24358799 ("bridge: netlink dump interface at par with brctl")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/vxlan.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 89d85dcb200e..5efe1e28f270 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -1376,6 +1376,7 @@ static int vxlan_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb, for (h = 0; h < FDB_HASH_SIZE; ++h) { struct vxlan_fdb *f; + rcu_read_lock(); hlist_for_each_entry_rcu(f, &vxlan->fdb_head[h], hlist) { struct vxlan_rdst *rd; @@ -1387,8 +1388,10 @@ static int vxlan_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb, cb->nlh->nlmsg_seq, RTM_NEWNEIGH, NLM_F_MULTI, NULL); - if (err < 0) + if (err < 0) { + rcu_read_unlock(); goto out; + } skip_nh: *idx += 1; continue; @@ -1403,12 +1406,15 @@ skip_nh: cb->nlh->nlmsg_seq, RTM_NEWNEIGH, NLM_F_MULTI, rd); - if (err < 0) + if (err < 0) { + rcu_read_unlock(); goto out; + } skip: *idx += 1; } } + rcu_read_unlock(); } out: return err; |