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authorIdo Schimmel <idosch@mellanox.com>2020-07-29 11:34:36 +0300
committerDavid S. Miller <davem@davemloft.net>2020-07-29 22:04:54 +0300
commitb5141915b5aec3b29a63db869229e3741ebce258 (patch)
tree0fb3c7d45c1714d6ccaed469fd018e1d38043e64 /drivers/net/vxlan.c
parent1ed06dbc213e1408ab60faa3ac0c0855a3ddc52d (diff)
downloadlinux-b5141915b5aec3b29a63db869229e3741ebce258.tar.xz
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>
Diffstat (limited to 'drivers/net/vxlan.c')
-rw-r--r--drivers/net/vxlan.c10
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;