| Message ID | 1508270973-23789-1-git-send-email-dsahern@gmail.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [v3,net-next] tcp: Remove use of daddr_cache in tracepoint | expand |
On Tue, Oct 17, 2017 at 1:09 PM, David Ahern <dsahern@gmail.com> wrote: > 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 > > Remove use of ipv6_pinfo in favor of data in sock_common. > > 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>
On Tue, 2017-10-17 at 13:09 -0700, David Ahern wrote: > 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: > Remove use of ipv6_pinfo in favor of data in sock_common. > > Fixes: e086101b150a ("tcp: add a tracepoint for tcp retransmission") > Signed-off-by: David Ahern <dsahern@gmail.com> > --- Reviewed-by: Eric Dumazet <edumazet@google.com> Thanks David !
From: David Ahern <dsahern@gmail.com> Date: Tue, 17 Oct 2017 13:09:33 -0700 > 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: ... > Remove use of ipv6_pinfo in favor of data in sock_common. > > Fixes: e086101b150a ("tcp: add a tracepoint for tcp retransmission") > Signed-off-by: David Ahern <dsahern@gmail.com> This doesn't apply to net-next, please respin. Thanks.
diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h index 3d1cbd072b7e..271812216ce3 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; @@ -44,12 +43,15 @@ TRACE_EVENT(tcp_retransmit_skb, p32 = (__be32 *) __entry->daddr; *p32 = inet->inet_daddr; - if (np) { +#if IS_ENABLED(CONFIG_IPV6) + if (sk->sk_family == AF_INET6) { 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); - } else { + *pin6 = sk->sk_v6_daddr; + } else +#endif + { pin6 = (struct in6_addr *)__entry->saddr_v6; ipv6_addr_set_v4mapped(inet->inet_saddr, pin6); pin6 = (struct in6_addr *)__entry->daddr_v6;
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 Remove use of ipv6_pinfo in favor of data in sock_common. Fixes: e086101b150a ("tcp: add a tracepoint for tcp retransmission") Signed-off-by: David Ahern <dsahern@gmail.com> --- v3 - remove use of inet6_sk and check sk_family (requested by Eric) - Add IS_ENABLED(CONFIG_IPV6) around use of sk_v6_rcv_saddr and sk_v6_daddr as done in sock_common (noted by Cong) v2 - remove np and get addresses from sock_common include/trace/events/tcp.h | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)