Re: [PATCH] tcp: another fix of uncloning packets before mangling them

The following warning was caught：

[937151.638394] Call Trace:
[937151.638401]  [<ffffffff8163f2f6>] dump_stack+0x19/0x1b
[937151.638405]  [<ffffffff8107dd70>] warn_slowpath_common+0x70/0xb0
[937151.638407]  [<ffffffff8107deba>] warn_slowpath_null+0x1a/0x20
[937151.638410]  [<ffffffff8158bb7b>] tcp_set_skb_tso_segs+0xeb/0x100
[937151.638412]  [<ffffffff8158bbc7>] tcp_init_tso_segs+0x37/0x50
[937151.638414]  [<ffffffff8158d7b9>] tcp_write_xmit+0x1d9/0xce0
[937151.638417]  [<ffffffff8158e53e>] __tcp_push_pending_frames+0x2e/0xc0
[937151.638419]  [<ffffffff8157cf3c>] tcp_push+0xec/0x120
[937151.638421]  [<ffffffff81580728>] tcp_sendmsg+0xc8/0xc20
[937151.638424]  [<ffffffff815aae24>] inet_sendmsg+0x64/0xb0
[937151.638428]  [<ffffffff810b9565>] ? check_preempt_curr+0x75/0xa0
[937151.638434]  [<ffffffff81519917>] sock_aio_write+0x157/0x180
[937151.638437]  [<ffffffff811e267d>] do_sync_write+0x8d/0xd0
[937151.638440]  [<ffffffff811e2f95>] vfs_write+0x1b5/0x1e0
[937151.638442]  [<ffffffff811e393f>] SyS_write+0x7f/0xe0
[937151.638445]  [<ffffffff816513fd>] system_call_fastpath+0x16/0x1b

According commit c52e2421f736 ("tcp: must unclone packets before
mangling them"), TCP stack should make sure it owns skbs before
mangling them.
And there is another place where skb_unclone() is needed. This patch
fix that.

Signed-off-by: Wen Yang <redacted>
Tested-by: Liu Bo <redacted>
Reviewed-by: Jiang Biao <redacted>
---
 net/ipv4/tcp_output.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 597dbd7..fbe8140 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c

@@ -1793,6 +1793,9 @@ static int tcp_init_tso_segs(struct sk_buff *skb, unsigned int mss_now)
        int tso_segs = tcp_skb_pcount(skb);