kernel/include/trace/events/tcp.h, branch linux-4.15.y

tcp: Avoid preprocessor directives in tracepoint macro args

2017-12-26T22:25:22Z

Using a preprocessor directive to check for CONFIG_IPV6 in the middle of a DECLARE_EVENT_CLASS macro's arg list causes sparse to report a series of errors: ./include/trace/events/tcp.h:68:1: error: directive in argument list ./include/trace/events/tcp.h:75:1: error: directive in argument list ./include/trace/events/tcp.h:144:1: error: directive in argument list ./include/trace/events/tcp.h:151:1: error: directive in argument list ./include/trace/events/tcp.h:216:1: error: directive in argument list ./include/trace/events/tcp.h:223:1: error: directive in argument list ./include/trace/events/tcp.h:274:1: error: directive in argument list ./include/trace/events/tcp.h:281:1: error: directive in argument list Once sparse finds an error, it stops printing warnings for the file it is checking. This masks any sparse warnings that would normally be reported for the core TCP code. Instead, handle the preprocessor conditionals in a couple of auxiliary macros. This also has the benefit of reducing duplicate code. Cc: David Ahern Signed-off-by: Mat Martineau Signed-off-by: David S. Miller

tcp: add tracepoint trace_tcp_retransmit_synack()

2017-11-03T01:12:45Z

This tracepoint can be used to trace synack retransmits. It maintains pointer to struct request_sock. We cannot simply reuse trace_tcp_retransmit_skb() here, because the sk here is the LISTEN socket. The IP addresses and ports should be extracted from struct request_sock. Note that, like many other tracepoints, this patch uses IS_ENABLED in TP_fast_assign macro, which triggers sparse warning like: ./include/trace/events/tcp.h:274:1: error: directive in argument list ./include/trace/events/tcp.h:281:1: error: directive in argument list However, there is no good solution to avoid these warnings. To the best of our knowledge, these warnings are harmless. Signed-off-by: Song Liu Acked-by: Alexei Starovoitov Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller

tcp: add tracepoint trace_tcp_set_state()

2017-10-24T00:21:25Z

This patch adds tracepoint trace_tcp_set_state. Besides usual fields (s/d ports, IP addresses), old and new state of the socket is also printed with TP_printk, with __print_symbolic(). Signed-off-by: Song Liu Signed-off-by: David S. Miller

tcp: add tracepoint trace_tcp_destroy_sock

2017-10-24T00:21:25Z

This patch adds trace event trace_tcp_destroy_sock. Signed-off-by: Song Liu Signed-off-by: David S. Miller

tcp: add tracepoint trace_tcp_receive_reset

2017-10-24T00:21:25Z

New tracepoint trace_tcp_receive_reset is added and called from tcp_reset(). This tracepoint is define with a new class tcp_event_sk. Signed-off-by: Song Liu Signed-off-by: David S. Miller

tcp: add tracepoint trace_tcp_send_reset

2017-10-24T00:21:25Z

New tracepoint trace_tcp_send_reset is added and called from tcp_v4_send_reset(), tcp_v6_send_reset() and tcp_send_active_reset(). Signed-off-by: Song Liu Signed-off-by: David S. Miller

tcp: mark trace event arguments sk and skb as const

2017-10-24T00:21:25Z

Some functions that we plan to add trace points require const sk and/or skb. So we mark these fields as const in the tracepoint. Signed-off-by: Song Liu Signed-off-by: David S. Miller

tcp: add trace event class tcp_event_sk_skb

2017-10-24T00:21:25Z

Introduce event class tcp_event_sk_skb for tcp tracepoints that have arguments sk and skb. Existing tracepoint trace_tcp_retransmit_skb() falls into this class. This patch rewrites the definition of trace_tcp_retransmit_skb() with tcp_event_sk_skb. Signed-off-by: Song Liu Signed-off-by: David S. Miller

tcp: Remove use of inet6_sk and add IPv6 checks to tracepoint

2017-10-20T12:04:58Z

386fd5da401d ("tcp: Check daddr_cache before use in tracepoint") was the second version of the tracepoint fixup patch. This patch is the delta between v2 and v3. Specifically, remove the use of inet6_sk and check sk_family as requested by Eric and add IS_ENABLED(CONFIG_IPV6) around the use of sk_v6_rcv_saddr and sk_v6_daddr as done in sock_common (noted by Cong). Signed-off-by: David Ahern Reviewed-by: Eric Dumazet Tested-by: Song Liu Signed-off-by: David S. Miller

tcp: Check daddr_cache before use in tracepoint

2017-10-18T13:15:14Z

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] [ 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 Acked-by: Cong Wang Signed-off-by: David S. Miller