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| author | Amol Grover <frextrite@gmail.com> | 2020-05-14 21:01:03 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-05-15 04:01:07 +0300 |
| commit | 7013908c2db285cd6b48fcd427a56354beac2233 (patch) | |
| tree | 6d400465a8018a4178d60deb595baa2b80b5ca4c /net | |
| parent | a14fbcd4f157a5a97b6013289205559d246c5021 (diff) | |
| download | linux-7013908c2db285cd6b48fcd427a56354beac2233.tar.xz | |
ipmr: Add lockdep expression to ipmr_for_each_table macro
During the initialization process, ipmr_new_table() is called
to create new tables which in turn calls ipmr_get_table() which
traverses net->ipv4.mr_tables without holding the writer lock.
However, this is safe to do so as no tables exist at this time.
Hence add a suitable lockdep expression to silence the following
false-positive warning:
=============================
WARNING: suspicious RCU usage
5.7.0-rc3-next-20200428-syzkaller #0 Not tainted
-----------------------------
net/ipv4/ipmr.c:136 RCU-list traversed in non-reader section!!
ipmr_get_table+0x130/0x160 net/ipv4/ipmr.c:136
ipmr_new_table net/ipv4/ipmr.c:403 [inline]
ipmr_rules_init net/ipv4/ipmr.c:248 [inline]
ipmr_net_init+0x133/0x430 net/ipv4/ipmr.c:3089
Fixes: f0ad0860d01e ("ipv4: ipmr: support multiple tables")
Reported-by: syzbot+1519f497f2f9f08183c6@syzkaller.appspotmail.com
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Amol Grover <frextrite@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/ipmr.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index 4897f7420c8f..5c218db2dede 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -109,9 +109,10 @@ static void mroute_clean_tables(struct mr_table *mrt, int flags); static void ipmr_expire_process(struct timer_list *t); #ifdef CONFIG_IP_MROUTE_MULTIPLE_TABLES -#define ipmr_for_each_table(mrt, net) \ - list_for_each_entry_rcu(mrt, &net->ipv4.mr_tables, list, \ - lockdep_rtnl_is_held()) +#define ipmr_for_each_table(mrt, net) \ + list_for_each_entry_rcu(mrt, &net->ipv4.mr_tables, list, \ + lockdep_rtnl_is_held() || \ + list_empty(&net->ipv4.mr_tables)) static struct mr_table *ipmr_mr_table_iter(struct net *net, struct mr_table *mrt) |