| Message ID | 20200319221141.8814-1-cai@lca.pw |
|---|---|
| State | New |
| Headers | show |
| Series | ipv4: fix a RCU-list bug in inet_dump_fib() | expand |
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index 577db1d50a24..5e441282d647 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -987,6 +987,8 @@ static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb) if (filter.flags & RTM_F_PREFIX) return skb->len; + rcu_read_lock(); + if (filter.table_id) { tb = fib_get_table(net, filter.table_id); if (!tb) { @@ -1004,8 +1006,6 @@ static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb) s_h = cb->args[0]; s_e = cb->args[1]; - rcu_read_lock(); - for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) { e = 0; head = &net->ipv4.fib_table_hash[h];
There is a place, inet_dump_fib() fib_table_dump fn_trie_dump_leaf() hlist_for_each_entry_rcu() without rcu_read_lock() triggers a warning, WARNING: suspicious RCU usage ----------------------------- net/ipv4/fib_trie.c:2216 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 ip/1923: #0: ffffffff8ce76e40 (rtnl_mutex){+.+.}, at: netlink_dump+0xd6/0x840 Call Trace: dump_stack+0xa1/0xea lockdep_rcu_suspicious+0x103/0x10d fn_trie_dump_leaf+0x581/0x590 fib_table_dump+0x15f/0x220 inet_dump_fib+0x4ad/0x5d0 netlink_dump+0x350/0x840 __netlink_dump_start+0x315/0x3e0 rtnetlink_rcv_msg+0x4d1/0x720 netlink_rcv_skb+0xf0/0x220 rtnetlink_rcv+0x15/0x20 netlink_unicast+0x306/0x460 netlink_sendmsg+0x44b/0x770 __sys_sendto+0x259/0x270 __x64_sys_sendto+0x80/0xa0 do_syscall_64+0x69/0xf4 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Signed-off-by: Qian Cai <cai@lca.pw> --- net/ipv4/fib_frontend.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)