From: Qian Cai <cai@lca.pw>
To: davem@davemloft.net
Cc: alexander.h.duyck@linux.intel.com, kuznet@ms2.inr.ac.ru,
kuba@kernel.org, yoshfuji@linux-ipv6.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, Qian Cai <cai@lca.pw>
Subject: [PATCH] ipv4: fix a RCU-list bug in inet_dump_fib()
Date: Thu, 19 Mar 2020 18:11:41 -0400 [thread overview]
Message-ID: <20200319221141.8814-1-cai@lca.pw> (raw)
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(-)
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];
--
2.21.0 (Apple Git-122.2)
next reply other threads:[~2020-03-19 22:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-19 22:11 Qian Cai [this message]
2020-03-19 22:15 ` [PATCH] ipv4: fix a RCU-list bug in inet_dump_fib() Qian Cai
2020-03-19 22:32 ` David Ahern
2020-03-25 3:04 ` [ipv4] f3f6f46e79: kernel-selftests.net.pmtu.sh.fail kernel test robot
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200319221141.8814-1-cai@lca.pw \
--to=cai@lca.pw \
--cc=alexander.h.duyck@linux.intel.com \
--cc=davem@davemloft.net \
--cc=kuba@kernel.org \
--cc=kuznet@ms2.inr.ac.ru \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=yoshfuji@linux-ipv6.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).