diff options
| author | Kuniyuki Iwashima <kuniyu@google.com> | 2026-09-14 01:14:01 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2026-09-15 15:13:22 +0200 |
| commit | 8e759cd1f6444a946bd1fd2b2b29eea582eea1d5 (patch) | |
| tree | 6b5c9ca4b112aaec71080297328ca7548cfbb06d | |
| parent | 0654f4dba1fbc697f2653aba30cd68587fcbf10e (diff) | |
| download | linux-next-8e759cd1f6444a946bd1fd2b2b29eea582eea1d5.tar.gz linux-next-8e759cd1f6444a946bd1fd2b2b29eea582eea1d5.zip | |
tcp: Don't call skb_clone_and_charge_r() for close()d listener in tcp_v6_do_rcv().
tcp_v6_do_rcv() no longer calls skb_clone_and_charge_r() for
TCP_LISTEN since commit 073d89808c06 ("net: fix data-races around
sk->sk_forward_alloc").
However, there is still a small race window between tcp_v6_rcv()
and tcp_v6_do_rcv(), where concurrent close() changes TCP_LISTEN
to TCP_CLOSE, causing skb_clone_and_charge_r() to be called
locklessly and resulting in the splat below. [0]
Let's avoid calling skb_clone_and_charge_r() for TCP_CLOSE as well.
This is fine for non-listeners because tcp_rcv_state_process()
drops skb for TCP_CLOSE and opt_skb was freed immediately anyway.
[0]:
sk->sk_forward_alloc
WARNING: net/ipv4/af_inet.c:162 at inet_sock_destruct+0x64d/0x810 net/ipv4/af_inet.c:162, CPU#1: ksoftirqd/1/28
Modules linked in:
CPU: 1 UID: 0 PID: 28 Comm: ksoftirqd/1 Not tainted 7.2.0 #17 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
RIP: 0010:inet_sock_destruct+0x64d/0x810 net/ipv4/af_inet.c:162
Code: 3d 49 ff e9 06 fd ff ff e8 d0 5b 83 f8 90 0f 0b 90 e9 35 fe ff ff e8 c2 5b 83 f8 90 0f 0b 90 e9 c5 fe ff ff e8 b4 5b 83 f8 90 <0f> 0b 90 e9 04 ff ff ff e8 a6 5b 83 f8 90 0f 0b 90 e9 65 fe ff ff
RSP: 0018:ffffc90000677bb8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8880117bde80 RCX: ffffffff8957eb41
RDX: ffff88801dad5d00 RSI: ffffffff8957ec3c RDI: 0000000000000005
RBP: 00000000fffff000 R08: ffffffff8957eb41 R09: 00000000fffff000
R10: 0000000000000005 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff8880117bdf10 R14: ffffffff81c08eb7 R15: 0000000000000003
FS: 0000000000000000(0000) GS:ffff8880d7ae5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f93a1021138 CR3: 00000000207a9000 CR4: 0000000000350ef0
Call Trace:
<TASK>
__sk_destruct+0x82/0xae0 net/core/sock.c:2356
rcu_do_batch kernel/rcu/tree.c:2645 [inline]
rcu_core+0x59c/0x1100 kernel/rcu/tree.c:2897
handle_softirqs+0x1e4/0x9b0 kernel/softirq.c:622
run_ksoftirqd kernel/softirq.c:1076 [inline]
run_ksoftirqd+0x38/0x60 kernel/softirq.c:1068
smpboot_thread_fn+0x458/0xc80 kernel/smpboot.c:160
kthread+0x396/0x4a0 kernel/kthread.c:436
ret_from_fork+0x8e0/0xe40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets")
Reported-by: Taras Madan <tarasmadan@google.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260914011420.115556-1-kuniyu@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index df9c29eb5c1f..7fa4ed2fd4f1 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1604,7 +1604,8 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) by tcp. Feel free to propose better solution. --ANK (980728) */ - if (np->rxopt.all && sk->sk_state != TCP_LISTEN) + if (np->rxopt.all && + !((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))) opt_skb = skb_clone_and_charge_r(skb, sk); if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ |