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| author | Eric Dumazet <edumazet@google.com> | 2013-03-22 14:38:28 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-03-24 17:27:27 -0400 |
| commit | 9979a55a833883242e3a29f3596676edd7199c46 (patch) | |
| tree | 062be0cfd4d65c4344f414f484b7242175861f62 /net/core | |
| parent | f4541d60a449afd40448b06496dcd510f505928e (diff) | |
| download | linux-9979a55a833883242e3a29f3596676edd7199c46.tar.bz2 | |
net: remove a WARN_ON() in net_enable_timestamp()
The WARN_ON(in_interrupt()) in net_enable_timestamp() can get false
positive, in socket clone path, run from softirq context :
[ 3641.624425] WARNING: at net/core/dev.c:1532 net_enable_timestamp+0x7b/0x80()
[ 3641.668811] Call Trace:
[ 3641.671254] <IRQ> [<ffffffff80286817>] warn_slowpath_common+0x87/0xc0
[ 3641.677871] [<ffffffff8028686a>] warn_slowpath_null+0x1a/0x20
[ 3641.683683] [<ffffffff80742f8b>] net_enable_timestamp+0x7b/0x80
[ 3641.689668] [<ffffffff80732ce5>] sk_clone_lock+0x425/0x450
[ 3641.695222] [<ffffffff8078db36>] inet_csk_clone_lock+0x16/0x170
[ 3641.701213] [<ffffffff807ae449>] tcp_create_openreq_child+0x29/0x820
[ 3641.707663] [<ffffffff807d62e2>] ? ipt_do_table+0x222/0x670
[ 3641.713354] [<ffffffff807aaf5b>] tcp_v4_syn_recv_sock+0xab/0x3d0
[ 3641.719425] [<ffffffff807af63a>] tcp_check_req+0x3da/0x530
[ 3641.724979] [<ffffffff8078b400>] ? inet_hashinfo_init+0x60/0x80
[ 3641.730964] [<ffffffff807ade6f>] ? tcp_v4_rcv+0x79f/0xbe0
[ 3641.736430] [<ffffffff807ab9bd>] tcp_v4_do_rcv+0x38d/0x4f0
[ 3641.741985] [<ffffffff807ae14a>] tcp_v4_rcv+0xa7a/0xbe0
Its safe at this point because the parent socket owns a reference
on the netstamp_needed, so we cant have a 0 -> 1 transition, which
requires to lock a mutex.
Instead of refining the check, lets remove it, as all known callers
are safe. If it ever changes in the future, static_key_slow_inc()
will complain anyway.
Reported-by: Laurent Chavey <chavey@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/dev.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index d540ced1f6c6..b13e5c766c11 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1545,7 +1545,6 @@ void net_enable_timestamp(void) return; } #endif - WARN_ON(in_interrupt()); static_key_slow_inc(&netstamp_needed); } EXPORT_SYMBOL(net_enable_timestamp); |