[PATCH] tcp: another fix of uncloning packets before mangling them
From: Wen Yang <hidden>
Date: 2018-08-28 07:32:57
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); if (!tso_segs || (tso_segs > 1 && tcp_skb_mss(skb) != mss_now)) { + if (skb_unclone(skb, GFP_ATOMIC)) + return -ENOMEM; + tcp_set_skb_tso_segs(skb, mss_now); tso_segs = tcp_skb_pcount(skb); }
@@ -2045,6 +2048,7 @@ static int tcp_mtu_probe(struct sock *sk) int copy, len; int mss_now; int interval; + int err; /* Not currently probing/verifying, * not in recovery,
@@ -2151,7 +2155,9 @@ static int tcp_mtu_probe(struct sock *sk) if (len >= probe_size) break; } - tcp_init_tso_segs(nskb, nskb->len); + err = tcp_init_tso_segs(nskb, nskb->len); + if (unlikely(err < 0)) + return err; /* We're ready to send. If this fails, the probe will * be resegmented into mss-sized pieces by tcp_write_xmit().
@@ -2309,6 +2315,8 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle, tso_segs = tcp_init_tso_segs(skb, mss_now); BUG_ON(!tso_segs); + if (unlikely(tso_segs < 0)) + break; if (unlikely(tp->repair) && tp->repair_queue == TCP_SEND_QUEUE) { /* "skb_mstamp" is used as a start point for the retransmit timer */
--
1.8.3.1