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| author | Eric Dumazet <edumazet@google.com> | 2012-08-28 12:33:07 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-08-30 13:33:08 -0400 |
| commit | c5ae7d41927dbd208c885d4794e30617ad6cdf12 (patch) | |
| tree | aa172acd3759bbcd191dac36336d1a6f123139a7 | |
| parent | 5c879d2094946081af934739850c7260e8b25d3c (diff) | |
| download | blackbird-obmc-linux-c5ae7d41927dbd208c885d4794e30617ad6cdf12.tar.gz blackbird-obmc-linux-c5ae7d41927dbd208c885d4794e30617ad6cdf12.zip | |
ipv4: must use rcu protection while calling fib_lookup
Following lockdep splat was reported by Pavel Roskin :
[ 1570.586223] ===============================
[ 1570.586225] [ INFO: suspicious RCU usage. ]
[ 1570.586228] 3.6.0-rc3-wl-main #98 Not tainted
[ 1570.586229] -------------------------------
[ 1570.586231] /home/proski/src/linux/net/ipv4/route.c:645 suspicious rcu_dereference_check() usage!
[ 1570.586233]
[ 1570.586233] other info that might help us debug this:
[ 1570.586233]
[ 1570.586236]
[ 1570.586236] rcu_scheduler_active = 1, debug_locks = 0
[ 1570.586238] 2 locks held by Chrome_IOThread/4467:
[ 1570.586240] #0: (slock-AF_INET){+.-...}, at: [<ffffffff814f2c0c>] release_sock+0x2c/0xa0
[ 1570.586253] #1: (fnhe_lock){+.-...}, at: [<ffffffff815302fc>] update_or_create_fnhe+0x2c/0x270
[ 1570.586260]
[ 1570.586260] stack backtrace:
[ 1570.586263] Pid: 4467, comm: Chrome_IOThread Not tainted 3.6.0-rc3-wl-main #98
[ 1570.586265] Call Trace:
[ 1570.586271] [<ffffffff810976ed>] lockdep_rcu_suspicious+0xfd/0x130
[ 1570.586275] [<ffffffff8153042c>] update_or_create_fnhe+0x15c/0x270
[ 1570.586278] [<ffffffff815305b3>] __ip_rt_update_pmtu+0x73/0xb0
[ 1570.586282] [<ffffffff81530619>] ip_rt_update_pmtu+0x29/0x90
[ 1570.586285] [<ffffffff815411dc>] inet_csk_update_pmtu+0x2c/0x80
[ 1570.586290] [<ffffffff81558d1e>] tcp_v4_mtu_reduced+0x2e/0xc0
[ 1570.586293] [<ffffffff81553bc4>] tcp_release_cb+0xa4/0xb0
[ 1570.586296] [<ffffffff814f2c35>] release_sock+0x55/0xa0
[ 1570.586300] [<ffffffff815442ef>] tcp_sendmsg+0x4af/0xf50
[ 1570.586305] [<ffffffff8156fc60>] inet_sendmsg+0x120/0x230
[ 1570.586308] [<ffffffff8156fb40>] ? inet_sk_rebuild_header+0x40/0x40
[ 1570.586312] [<ffffffff814f4bdd>] ? sock_update_classid+0xbd/0x3b0
[ 1570.586315] [<ffffffff814f4c50>] ? sock_update_classid+0x130/0x3b0
[ 1570.586320] [<ffffffff814ec435>] do_sock_write+0xc5/0xe0
[ 1570.586323] [<ffffffff814ec4a3>] sock_aio_write+0x53/0x80
[ 1570.586328] [<ffffffff8114bc83>] do_sync_write+0xa3/0xe0
[ 1570.586332] [<ffffffff8114c5a5>] vfs_write+0x165/0x180
[ 1570.586335] [<ffffffff8114c805>] sys_write+0x45/0x90
[ 1570.586340] [<ffffffff815d2722>] system_call_fastpath+0x16/0x1b
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/route.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 24fd4c596643..82cf2a722b23 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -934,12 +934,14 @@ static u32 __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) if (mtu < ip_rt_min_pmtu) mtu = ip_rt_min_pmtu; + rcu_read_lock(); if (fib_lookup(dev_net(rt->dst.dev), fl4, &res) == 0) { struct fib_nh *nh = &FIB_RES_NH(res); update_or_create_fnhe(nh, fl4->daddr, 0, mtu, jiffies + ip_rt_mtu_expires); } + rcu_read_unlock(); return mtu; } |
