| Message ID | 20200320025421.9216-1-cai@lca.pw |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | [v2] ipv4: fix a RCU-list lock in inet_dump_fib() | expand |
On 3/19/20 8:54 PM, Qian Cai wrote: > There is a place, > > inet_dump_fib() > fib_table_dump > fn_trie_dump_leaf() > hlist_for_each_entry_rcu() > > without rcu_read_lock() will trigger 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 > > Fixes: 18a8021a7be3 ("net/ipv4: Plumb support for filtering route dumps") > Signed-off-by: Qian Cai <cai@lca.pw> > --- > > v2: Call rcu_read_unlock() before returning. > Add a "Fixes" tag per David. > > net/ipv4/fib_frontend.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c > index 577db1d50a24..213be9c050ad 100644 > --- a/net/ipv4/fib_frontend.c > +++ b/net/ipv4/fib_frontend.c > @@ -997,7 +997,9 @@ static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb) > return -ENOENT; > } > > + rcu_read_lock(); > err = fib_table_dump(tb, skb, cb, &filter); > + rcu_read_unlock(); > return skb->len ? : err; > } > > Reviewed-by: David Ahern <dsahern@gmail.com>
From: Qian Cai <cai@lca.pw> Date: Thu, 19 Mar 2020 22:54:21 -0400 > There is a place, > > inet_dump_fib() > fib_table_dump > fn_trie_dump_leaf() > hlist_for_each_entry_rcu() > > without rcu_read_lock() will trigger a warning, > > WARNING: suspicious RCU usage ... > Fixes: 18a8021a7be3 ("net/ipv4: Plumb support for filtering route dumps") > Signed-off-by: Qian Cai <cai@lca.pw> Applied and queued up for -stable, thank you.
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index 577db1d50a24..213be9c050ad 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -997,7 +997,9 @@ static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb) return -ENOENT; } + rcu_read_lock(); err = fib_table_dump(tb, skb, cb, &filter); + rcu_read_unlock(); return skb->len ? : err; }
There is a place, inet_dump_fib() fib_table_dump fn_trie_dump_leaf() hlist_for_each_entry_rcu() without rcu_read_lock() will trigger 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 Fixes: 18a8021a7be3 ("net/ipv4: Plumb support for filtering route dumps") Signed-off-by: Qian Cai <cai@lca.pw> --- v2: Call rcu_read_unlock() before returning. Add a "Fixes" tag per David. net/ipv4/fib_frontend.c | 2 ++ 1 file changed, 2 insertions(+)