diff options
| author | David Ahern <dsahern@gmail.com> | 2017-10-17 01:32:07 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-10-18 16:15:14 +0300 |
| commit | 386fd5da401dc6c4b0ab6a54d333609876b699fe (patch) | |
| tree | 671acdf97ad039785e0f0350714786ca25bfed36 /include | |
| parent | d4f4da3e13ae7a405fa1da11ff4070588e700445 (diff) | |
| download | linux-386fd5da401dc6c4b0ab6a54d333609876b699fe.tar.xz | |
tcp: Check daddr_cache before use in tracepoint
Running perf in one window to capture tcp_retransmit_skb tracepoint:
$ perf record -e tcp:tcp_retransmit_skb -a
And causing a retransmission on an active TCP session (e.g., dropping
packets in the receiver, changing MTU on the interface to 500 and back
to 1500) triggers a panic:
[ 58.543144] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[ 58.545300] IP: perf_trace_tcp_retransmit_skb+0xd0/0x145
[ 58.546770] PGD 0 P4D 0
[ 58.547472] Oops: 0000 [#1] SMP
[ 58.548328] Modules linked in: vrf
[ 58.549262] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.14.0-rc4+ #26
[ 58.551004] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[ 58.554560] task: ffffffff81a0e540 task.stack: ffffffff81a00000
[ 58.555817] RIP: 0010:perf_trace_tcp_retransmit_skb+0xd0/0x145
[ 58.557137] RSP: 0018:ffff88003fc03d68 EFLAGS: 00010282
[ 58.558292] RAX: 0000000000000000 RBX: ffffe8ffffc0ec80 RCX: ffff880038543098
[ 58.559850] RDX: 0400000000000000 RSI: ffff88003fc03d70 RDI: ffff88003fc14b68
[ 58.561099] RBP: ffff88003fc03da8 R08: 0000000000000000 R09: ffffea0000d3224a
[ 58.562005] R10: ffff88003fc03db8 R11: 0000000000000010 R12: ffff8800385428c0
[ 58.562930] R13: ffffe8ffffc0e478 R14: ffffffff81a93a40 R15: ffff88003d4f0c00
[ 58.563845] FS: 0000000000000000(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
[ 58.564873] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 58.565613] CR2: 0000000000000008 CR3: 000000003d68f004 CR4: 00000000000606f0
[ 58.566538] Call Trace:
[ 58.566865] <IRQ>
[ 58.567140] __tcp_retransmit_skb+0x4ab/0x4c6
[ 58.567704] ? tcp_set_ca_state+0x22/0x3f
[ 58.568231] tcp_retransmit_skb+0x14/0xa3
[ 58.568754] tcp_retransmit_timer+0x472/0x5e3
[ 58.569324] ? tcp_write_timer_handler+0x1e9/0x1e9
[ 58.569946] tcp_write_timer_handler+0x95/0x1e9
[ 58.570548] tcp_write_timer+0x2a/0x58
Check that daddr_cache is non-NULL before de-referencing.
Fixes: e086101b150a ("tcp: add a tracepoint for tcp retransmission")
Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
| -rw-r--r-- | include/trace/events/tcp.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h index 1ffab6d96e94..f51c130f1e0f 100644 --- a/include/trace/events/tcp.h +++ b/include/trace/events/tcp.h @@ -27,7 +27,6 @@ TRACE_EVENT(tcp_retransmit_skb, ), TP_fast_assign( - struct ipv6_pinfo *np = inet6_sk(sk); struct inet_sock *inet = inet_sk(sk); struct in6_addr *pin6; __be32 *p32; @@ -44,11 +43,12 @@ TRACE_EVENT(tcp_retransmit_skb, p32 = (__be32 *) __entry->daddr; *p32 = inet->inet_daddr; - if (np) { + /* IPv6 socket ? */ + if (inet6_sk(sk)) { pin6 = (struct in6_addr *)__entry->saddr_v6; - *pin6 = np->saddr; + *pin6 = sk->sk_v6_rcv_saddr; pin6 = (struct in6_addr *)__entry->daddr_v6; - *pin6 = *(np->daddr_cache); + *pin6 = sk->sk_v6_daddr; } else { pin6 = (struct in6_addr *)__entry->saddr_v6; ipv6_addr_set_v4mapped(inet->inet_saddr, pin6); |