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2025-05-29Merge tag 'trace-v6.16' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing updates from Steven Rostedt: - Have module addresses get updated in the persistent ring buffer The addresses of the modules from the previous boot are saved in the persistent ring buffer. If the same modules are loaded and an address is in the old buffer points to an address that was both saved in the persistent ring buffer and is loaded in memory, shift the address to point to the address that is loaded in memory in the trace event. - Print function names for irqs off and preempt off callsites When ignoring the print fmt of a trace event and just printing the fields directly, have the fields for preempt off and irqs off events still show the function name (via kallsyms) instead of just showing the raw address. - Clean ups of the histogram code The histogram functions saved over 800 bytes on the stack to process events as they come in. Instead, create per-cpu buffers that can hold this information and have a separate location for each context level (thread, softirq, IRQ and NMI). Also add some more comments to the code. - Add "common_comm" field for histograms Add "common_comm" that uses the current->comm as a field in an event histogram and acts like any of the other fields of the event. - Show "subops" in the enabled_functions file When the function graph infrastructure is used, a subsystem has a "subops" that it attaches its callback function to. Instead of the enabled_functions just showing a function calling the function that calls the subops functions, also show the subops functions that will get called for that function too. - Add "copy_trace_marker" option to instances There are cases where an instance is created for tooling to write into, but the old tooling has the top level instance hardcoded into the application. New tools want to consume the data from an instance and not the top level buffer. By adding a copy_trace_marker option, whenever the top instance trace_marker is written into, a copy of it is also written into the instance with this option set. This allows new tools to read what old tools are writing into the top buffer. If this option is cleared by the top instance, then what is written into the trace_marker is not written into the top instance. This is a way to redirect the trace_marker writes into another instance. - Have tracepoints created by DECLARE_TRACE() use trace_<name>_tp() If a tracepoint is created by DECLARE_TRACE() instead of TRACE_EVENT(), then it will not be exposed via tracefs. Currently there's no way to differentiate in the kernel the tracepoint functions between those that are exposed via tracefs or not. A calling convention has been made manually to append a "_tp" prefix for events created by DECLARE_TRACE(). Instead of doing this manually, force it so that all DECLARE_TRACE() events have this notation. - Use __string() for task->comm in some sched events Instead of hardcoding the comm to be TASK_COMM_LEN in some of the scheduler events use __string() which makes it dynamic. Note, if these events are parsed by user space it they may break, and the event may have to be converted back to the hardcoded size. - Have function graph "depth" be unsigned to the user Internally to the kernel, the "depth" field of the function graph event is signed due to -1 being used for end of boundary. What actually gets recorded in the event itself is zero or positive. Reflect this to user space by showing "depth" as unsigned int and be consistent across all events. - Allow an arbitrary long CPU string to osnoise_cpus_write() The filtering of which CPUs to write to can exceed 256 bytes. If a machine has 256 CPUs, and the filter is to filter every other CPU, the write would take a string larger than 256 bytes. Instead of using a fixed size buffer on the stack that is 256 bytes, allocate it to handle what is passed in. - Stop having ftrace check the per-cpu data "disabled" flag The "disabled" flag in the data structure passed to most ftrace functions is checked to know if tracing has been disabled or not. This flag was added back in 2008 before the ring buffer had its own way to disable tracing. The "disable" flag is now not always set when needed, and the ring buffer flag should be used in all locations where the disabled is needed. Since the "disable" flag is redundant and incorrect, stop using it. Fix up some locations that use the "disable" flag to use the ring buffer info. - Use a new tracer_tracing_disable/enable() instead of data->disable flag There's a few cases that set the data->disable flag to stop tracing, but this flag is not consistently used. It is also an on/off switch where if a function set it and calls another function that sets it, the called function may incorrectly enable it. Use a new trace_tracing_disable() and tracer_tracing_enable() that uses a counter and can be nested. These use the ring buffer flags which are always checked making the disabling more consistent. - Save the trace clock in the persistent ring buffer Save what clock was used for tracing in the persistent ring buffer and set it back to that clock after a reboot. - Remove unused reference to a per CPU data pointer in mmiotrace functions - Remove unused buffer_page field from trace_array_cpu structure - Remove more strncpy() instances - Other minor clean ups and fixes * tag 'trace-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (36 commits) tracing: Fix compilation warning on arm32 tracing: Record trace_clock and recover when reboot tracing/sched: Use __string() instead of fixed lengths for task->comm tracepoint: Have tracepoints created with DECLARE_TRACE() have _tp suffix tracing: Cleanup upper_empty() in pid_list tracing: Allow the top level trace_marker to write into another instances tracing: Add a helper function to handle the dereference arg in verifier tracing: Remove unnecessary "goto out" that simply returns ret is trigger code tracing: Fix error handling in event_trigger_parse() tracing: Rename event_trigger_alloc() to trigger_data_alloc() tracing: Replace deprecated strncpy() with strscpy() for stack_trace_filter_buf tracing: Remove unused buffer_page field from trace_array_cpu structure tracing: Use atomic_inc_return() for updating "disabled" counter in irqsoff tracer tracing: Convert the per CPU "disabled" counter to local from atomic tracing: branch: Use trace_tracing_is_on_cpu() instead of "disabled" field ring-buffer: Add ring_buffer_record_is_on_cpu() tracing: Do not use per CPU array_buffer.data->disabled for cpumask ftrace: Do not disabled function graph based on "disabled" field tracing: kdb: Use tracer_tracing_on/off() instead of setting per CPU disabled tracing: Use tracer_tracing_disable() instead of "disabled" field for ftrace_dump_one() ...
2025-05-15tcp: add tcp_rcvbuf_grow() tracepointEric Dumazet
Provide a new tracepoint to better understand tcp_rcv_space_adjust() (currently broken) behavior. Call it only when tcp_rcv_space_adjust() has a chance to make a change. I chose to leave trace_tcp_rcv_space_adjust() as is, because commit 6163849d289b ("net: introduce a new tracepoint for tcp_rcv_space_adjust") intent was to get it called after each data delivery to user space. Tested: Pair of hosts in the same rack. Ideally, sk->sk_rcvbuf should be kept small. echo "4096 131072 33554432" >/proc/sys/net/ipv4/tcp_rmem ./netserver perf record -C10 -e tcp:tcp_rcvbuf_grow sleep 30 <launch from client : netperf -H server -T,10> Trace for a TS enabled TCP flow (with standard ms granularity) perf script // We can see that sk_rcvbuf is growing very fast to tcp_mem[2] 260.500397: tcp:tcp_rcvbuf_grow: time=291 rtt_us=274 copied=110592 inq=0 space=41080 ooo=0 scaling_ratio=230 rcvbuf=131072 ... 260.501333: tcp:tcp_rcvbuf_grow: time=555 rtt_us=364 copied=333824 inq=0 space=110592 ooo=0 scaling_ratio=230 rcvbuf=1399144 ... 260.501664: tcp:tcp_rcvbuf_grow: time=331 rtt_us=330 copied=798720 inq=0 space=333824 ooo=0 scaling_ratio=230 rcvbuf=4110551 ... 260.502003: tcp:tcp_rcvbuf_grow: time=340 rtt_us=330 copied=1040384 inq=49152 space=798720 ooo=0 scaling_ratio=230 rcvbuf=7006410 ... 260.502483: tcp:tcp_rcvbuf_grow: time=479 rtt_us=330 copied=2658304 inq=49152 space=1040384 ooo=0 scaling_ratio=230 rcvbuf=7006410 ... 260.502899: tcp:tcp_rcvbuf_grow: time=416 rtt_us=413 copied=4026368 inq=147456 space=2658304 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.504233: tcp:tcp_rcvbuf_grow: time=493 rtt_us=487 copied=4800512 inq=196608 space=4026368 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.504792: tcp:tcp_rcvbuf_grow: time=559 rtt_us=551 copied=5672960 inq=49152 space=4800512 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.506614: tcp:tcp_rcvbuf_grow: time=610 rtt_us=607 copied=6688768 inq=180224 space=5672960 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.507280: tcp:tcp_rcvbuf_grow: time=666 rtt_us=656 copied=6868992 inq=49152 space=6688768 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.507979: tcp:tcp_rcvbuf_grow: time=699 rtt_us=699 copied=7000064 inq=0 space=6868992 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.508681: tcp:tcp_rcvbuf_grow: time=703 rtt_us=699 copied=7208960 inq=0 space=7000064 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.509426: tcp:tcp_rcvbuf_grow: time=744 rtt_us=737 copied=7569408 inq=0 space=7208960 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.510213: tcp:tcp_rcvbuf_grow: time=787 rtt_us=770 copied=7880704 inq=49152 space=7569408 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.511013: tcp:tcp_rcvbuf_grow: time=801 rtt_us=798 copied=8339456 inq=0 space=7880704 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.511860: tcp:tcp_rcvbuf_grow: time=847 rtt_us=824 copied=8601600 inq=49152 space=8339456 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.512710: tcp:tcp_rcvbuf_grow: time=850 rtt_us=846 copied=8814592 inq=65536 space=8601600 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.514428: tcp:tcp_rcvbuf_grow: time=871 rtt_us=865 copied=8855552 inq=49152 space=8814592 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.515333: tcp:tcp_rcvbuf_grow: time=905 rtt_us=882 copied=9228288 inq=49152 space=8855552 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.516237: tcp:tcp_rcvbuf_grow: time=905 rtt_us=896 copied=9371648 inq=49152 space=9228288 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.517149: tcp:tcp_rcvbuf_grow: time=911 rtt_us=909 copied=9543680 inq=49152 space=9371648 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.518070: tcp:tcp_rcvbuf_grow: time=921 rtt_us=921 copied=9793536 inq=0 space=9543680 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.520895: tcp:tcp_rcvbuf_grow: time=948 rtt_us=947 copied=10203136 inq=114688 space=9793536 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.521853: tcp:tcp_rcvbuf_grow: time=959 rtt_us=954 copied=10293248 inq=57344 space=10203136 ooo=0 scaling_ratio=230 rcvbuf=24691992 ... 260.522818: tcp:tcp_rcvbuf_grow: time=964 rtt_us=959 copied=10330112 inq=0 space=10293248 ooo=0 scaling_ratio=230 rcvbuf=24691992 ... 260.524760: tcp:tcp_rcvbuf_grow: time=979 rtt_us=969 copied=10633216 inq=49152 space=10330112 ooo=0 scaling_ratio=230 rcvbuf=24691992 ... 260.526709: tcp:tcp_rcvbuf_grow: time=975 rtt_us=973 copied=12013568 inq=163840 space=10633216 ooo=0 scaling_ratio=230 rcvbuf=25136755 ... 260.527694: tcp:tcp_rcvbuf_grow: time=985 rtt_us=976 copied=12025856 inq=32768 space=12013568 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.530655: tcp:tcp_rcvbuf_grow: time=991 rtt_us=986 copied=12050432 inq=98304 space=12025856 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.533626: tcp:tcp_rcvbuf_grow: time=993 rtt_us=989 copied=12124160 inq=0 space=12050432 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.538606: tcp:tcp_rcvbuf_grow: time=1000 rtt_us=994 copied=12222464 inq=49152 space=12124160 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.545605: tcp:tcp_rcvbuf_grow: time=1005 rtt_us=998 copied=12263424 inq=81920 space=12222464 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.553626: tcp:tcp_rcvbuf_grow: time=1005 rtt_us=999 copied=12320768 inq=12288 space=12263424 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.589749: tcp:tcp_rcvbuf_grow: time=1001 rtt_us=1000 copied=12398592 inq=16384 space=12320768 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.806577: tcp:tcp_rcvbuf_grow: time=1010 rtt_us=1000 copied=12402688 inq=32768 space=12398592 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 261.002386: tcp:tcp_rcvbuf_grow: time=1002 rtt_us=1000 copied=12419072 inq=98304 space=12402688 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 261.803432: tcp:tcp_rcvbuf_grow: time=1013 rtt_us=1000 copied=12468224 inq=49152 space=12419072 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 261.829533: tcp:tcp_rcvbuf_grow: time=1004 rtt_us=1000 copied=12615680 inq=0 space=12468224 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 265.505435: tcp:tcp_rcvbuf_grow: time=1007 rtt_us=1000 copied=12632064 inq=32768 space=12615680 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... We also see rtt_us going gradually to 1000 usec, causing massive overshoot. Trace for a usec TS enabled TCP flow (us granularity) perf script // We can see that sk_rcvbuf is growing to a smaller value, thanks to tight rtt_us values. 1509.273955: tcp:tcp_rcvbuf_grow: time=396 rtt_us=377 copied=110592 inq=0 space=41080 ooo=0 scaling_ratio=230 rcvbuf=131072 ... 1509.274366: tcp:tcp_rcvbuf_grow: time=412 rtt_us=365 copied=129024 inq=0 space=110592 ooo=0 scaling_ratio=230 rcvbuf=1399144 ... 1509.274738: tcp:tcp_rcvbuf_grow: time=372 rtt_us=355 copied=194560 inq=0 space=129024 ooo=0 scaling_ratio=230 rcvbuf=1399144 ... 1509.275020: tcp:tcp_rcvbuf_grow: time=282 rtt_us=257 copied=401408 inq=0 space=194560 ooo=0 scaling_ratio=230 rcvbuf=1399144 ... 1509.275190: tcp:tcp_rcvbuf_grow: time=170 rtt_us=144 copied=741376 inq=229376 space=401408 ooo=0 scaling_ratio=230 rcvbuf=3021625 ... 1509.275300: tcp:tcp_rcvbuf_grow: time=110 rtt_us=110 copied=1146880 inq=65536 space=741376 ooo=0 scaling_ratio=230 rcvbuf=4642390 ... 1509.275449: tcp:tcp_rcvbuf_grow: time=149 rtt_us=106 copied=1310720 inq=737280 space=1146880 ooo=0 scaling_ratio=230 rcvbuf=5498637 ... 1509.275560: tcp:tcp_rcvbuf_grow: time=111 rtt_us=107 copied=1388544 inq=430080 space=1310720 ooo=0 scaling_ratio=230 rcvbuf=5498637 ... 1509.275674: tcp:tcp_rcvbuf_grow: time=114 rtt_us=113 copied=1495040 inq=421888 space=1388544 ooo=0 scaling_ratio=230 rcvbuf=5498637 ... 1509.275800: tcp:tcp_rcvbuf_grow: time=126 rtt_us=126 copied=1572864 inq=77824 space=1495040 ooo=0 scaling_ratio=230 rcvbuf=5498637 ... 1509.275968: tcp:tcp_rcvbuf_grow: time=168 rtt_us=161 copied=1863680 inq=172032 space=1572864 ooo=0 scaling_ratio=230 rcvbuf=5498637 ... 1509.276129: tcp:tcp_rcvbuf_grow: time=161 rtt_us=161 copied=1941504 inq=204800 space=1863680 ooo=0 scaling_ratio=230 rcvbuf=5782790 ... 1509.276288: tcp:tcp_rcvbuf_grow: time=159 rtt_us=158 copied=1990656 inq=131072 space=1941504 ooo=0 scaling_ratio=230 rcvbuf=5782790 ... 1509.276900: tcp:tcp_rcvbuf_grow: time=228 rtt_us=226 copied=2883584 inq=266240 space=1990656 ooo=0 scaling_ratio=230 rcvbuf=5782790 ... 1509.277819: tcp:tcp_rcvbuf_grow: time=242 rtt_us=236 copied=3022848 inq=0 space=2883584 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.278072: tcp:tcp_rcvbuf_grow: time=253 rtt_us=247 copied=3055616 inq=49152 space=3022848 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.279560: tcp:tcp_rcvbuf_grow: time=268 rtt_us=264 copied=3133440 inq=180224 space=3055616 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.279833: tcp:tcp_rcvbuf_grow: time=274 rtt_us=270 copied=3424256 inq=0 space=3133440 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.282187: tcp:tcp_rcvbuf_grow: time=277 rtt_us=273 copied=3465216 inq=180224 space=3424256 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.284685: tcp:tcp_rcvbuf_grow: time=292 rtt_us=292 copied=3481600 inq=147456 space=3465216 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.284983: tcp:tcp_rcvbuf_grow: time=297 rtt_us=295 copied=3702784 inq=45056 space=3481600 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.285596: tcp:tcp_rcvbuf_grow: time=311 rtt_us=310 copied=3723264 inq=40960 space=3702784 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.285909: tcp:tcp_rcvbuf_grow: time=313 rtt_us=304 copied=3846144 inq=196608 space=3723264 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.291654: tcp:tcp_rcvbuf_grow: time=322 rtt_us=311 copied=3960832 inq=49152 space=3846144 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.291986: tcp:tcp_rcvbuf_grow: time=333 rtt_us=330 copied=4075520 inq=360448 space=3960832 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.292319: tcp:tcp_rcvbuf_grow: time=332 rtt_us=332 copied=4079616 inq=65536 space=4075520 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.292666: tcp:tcp_rcvbuf_grow: time=348 rtt_us=347 copied=4177920 inq=212992 space=4079616 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.293015: tcp:tcp_rcvbuf_grow: time=349 rtt_us=345 copied=4276224 inq=262144 space=4177920 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.293371: tcp:tcp_rcvbuf_grow: time=356 rtt_us=346 copied=4415488 inq=49152 space=4276224 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.515798: tcp:tcp_rcvbuf_grow: time=424 rtt_us=411 copied=4833280 inq=81920 space=4415488 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Wei Wang <weiwan@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Link: https://patch.msgid.link/20250513193919.1089692-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-14tracepoint: Have tracepoints created with DECLARE_TRACE() have _tp suffixSteven Rostedt
Most tracepoints in the kernel are created with TRACE_EVENT(). The TRACE_EVENT() macro (and DECLARE_EVENT_CLASS() and DEFINE_EVENT() where in reality, TRACE_EVENT() is just a helper macro that calls those other two macros), will create not only a tracepoint (the function trace_<event>() used in the kernel), it also exposes the tracepoint to user space along with defining what fields will be saved by that tracepoint. There are a few places that tracepoints are created in the kernel that are not exposed to userspace via tracefs. They can only be accessed from code within the kernel. These tracepoints are created with DEFINE_TRACE() Most of these tracepoints end with "_tp". This is useful as when the developer sees that, they know that the tracepoint is for in-kernel only (meaning it can only be accessed inside the kernel, either directly by the kernel or indirectly via modules and BPF programs) and is not exposed to user space. Instead of making this only a process to add "_tp", enforce it by making the DECLARE_TRACE() append the "_tp" suffix to the tracepoint. This requires adding DECLARE_TRACE_EVENT() macros for the TRACE_EVENT() macro to use that keeps the original name. Link: https://lore.kernel.org/all/20250418083351.20a60e64@gandalf.local.home/ Cc: netdev <netdev@vger.kernel.org> Cc: Jiri Olsa <olsajiri@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Ahern <dsahern@kernel.org> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Breno Leitao <leitao@debian.org> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Gabriele Monaco <gmonaco@redhat.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lore.kernel.org/20250510163730.092fad5b@gandalf.local.home Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-04-17trace: tcp: Add const qualifier to skb parameter in tcp_probe eventBreno Leitao
Change the tcp_probe tracepoint to accept a const struct sk_buff parameter instead of a non-const one. This improves type safety and better reflects that the skb is not modified within the tracepoint implementation. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250416-tcp_probe-v1-1-1edc3c5a1cb8@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-10trace: tcp: Add tracepoint for tcp_sendmsg_locked()Breno Leitao
Add a tracepoint to monitor TCP send operations, enabling detailed visibility into TCP message transmission. Create a new tracepoint within the tcp_sendmsg_locked function, capturing traditional fields along with size_goal, which indicates the optimal data size for a single TCP segment. Additionally, a reference to the struct sock sk is passed, allowing direct access for BPF programs. The implementation is largely based on David's patch[1] and suggestions. Link: https://lore.kernel.org/all/70168c8f-bf52-4279-b4c4-be64527aa1ac@kernel.org/ [1] Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250408-tcpsendmsg-v3-2-208b87064c28@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-18trace: tcp: Add tracepoint for tcp_cwnd_reduction()Breno Leitao
Add a lightweight tracepoint to monitor TCP congestion window adjustments via tcp_cwnd_reduction(). This tracepoint enables tracking of: - TCP window size fluctuations - Active socket behavior - Congestion window reduction events Meta has been using BPF programs to monitor this function for years. Adding a proper tracepoint provides a stable API for all users who need to monitor TCP congestion window behavior. Use DECLARE_TRACE instead of TRACE_EVENT to avoid creating trace event infrastructure and exporting to tracefs, keeping the implementation minimal. (Thanks Steven Rostedt) Given that this patch creates a rawtracepoint, you could hook into it using regular tooling, like bpftrace, using regular rawtracepoint infrastructure, such as: rawtracepoint:tcp_cwnd_reduction_tp { .... } Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250214-cwnd_tracepoint-v2-1-ef8d15162d95@debian.org Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-09-11tcp: Use skb__nullable in trace_tcp_send_resetPhilo Lu
Replace skb with skb__nullable as the argument name. The suffix tells bpf verifier through btf that the arg could be NULL and should be checked in tp_btf prog. For now, this is the only nullable argument in tcp tracepoints. Signed-off-by: Philo Lu <lulie@linux.alibaba.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Link: https://lore.kernel.org/r/20240911033719.91468-4-lulie@linux.alibaba.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2024-06-12net/tcp: Add tcp-md5 and tcp-ao tracepointsDmitry Safonov
Instead of forcing userspace to parse dmesg (that's what currently is happening, at least in codebase of my current company), provide a better way, that can be enabled/disabled in runtime. Currently, there are already tcp events, add hashing related ones there, too. Rasdaemon currently exercises net_dev_xmit_timeout, devlink_health_report, but it'll be trivial to teach it to deal with failed hashes. Otherwise, BGP may trace/log them itself. Especially exciting for possible investigations is key rotation (RNext_key requests). Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-04-26rstreason: make it work in trace worldJason Xing
At last, we should let it work by introducing this reset reason in trace world. One of the possible expected outputs is: ... tcp_send_reset: skbaddr=xxx skaddr=xxx src=xxx dest=xxx state=TCP_ESTABLISHED reason=NOT_SPECIFIED Signed-off-by: Jason Xing <kernelxing@tencent.com> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-04-03trace: tcp: fully support trace_tcp_send_resetJason Xing
Prior to this patch, what we can see by enabling trace_tcp_send is only happening under two circumstances: 1) active rst mode 2) non-active rst mode and based on the full socket That means the inconsistency occurs if we use tcpdump and trace simultaneously to see how rst happens. It's necessary that we should take into other cases into considerations, say: 1) time-wait socket 2) no socket ... By parsing the incoming skb and reversing its 4-tuple can we know the exact 'flow' which might not exist. Samples after applied this patch: 1. tcp_send_reset: skbaddr=XXX skaddr=XXX src=ip:port dest=ip:port state=TCP_ESTABLISHED 2. tcp_send_reset: skbaddr=000...000 skaddr=XXX src=ip:port dest=ip:port state=UNKNOWN Note: 1) UNKNOWN means we cannot extract the right information from skb. 2) skbaddr/skaddr could be 0 Signed-off-by: Jason Xing <kernelxing@tencent.com> Link: https://lore.kernel.org/r/20240401073605.37335-3-kerneljasonxing@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-04-03trace: adjust TP_STORE_ADDR_PORTS_SKB() parametersJason Xing
Introducing entry_saddr and entry_daddr parameters in this macro for later use can help us record the reverse 4-tuple by analyzing the 4-tuple of the incoming skb when receiving. Signed-off-by: Jason Xing <kernelxing@tencent.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20240401073605.37335-2-kerneljasonxing@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-03-29net: port TP_STORE_ADDR_PORTS_SKB macro to be tcp/udp independentBalazs Scheidler
This patch moves TP_STORE_ADDR_PORTS_SKB() to a common header and removes the TCP specific implementation details. Previously the macro assumed the skb passed as an argument is a TCP packet, the implementation now uses an argument to the L4 header and uses that to extract the source/destination ports, which happen to be named the same in "struct tcphdr" and "struct udphdr" Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Signed-off-by: Balazs Scheidler <balazs.scheidler@axoflow.com> Link: https://lore.kernel.org/r/9e306f78260dfbbdc7353ba5f864cc027a409540.1711475011.git.balazs.scheidler@axoflow.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-03-26trace: move to TP_STORE_ADDRS related macro to net_probe_common.hJason Xing
Put the macro into another standalone file for better extension. Some tracepoints can use this common part in the future. Signed-off-by: Jason Xing <kernelxing@tencent.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-03-08tcp: Add skb addr and sock addr to arguments of tracepoint tcp_probe.fuyuanli
It is useful to expose skb addr and sock addr to user in tracepoint tcp_probe, so that we can get more information while monitoring receiving of tcp data, by ebpf or other ways. For example, we need to identify a packet by seq and end_seq when calculate transmit latency between layer 2 and layer 4 by ebpf, but which is not available in tcp_probe, so we can only use kprobe hooking tcp_rcv_established to get them. But we can use tcp_probe directly if skb addr and sock addr are available, which is more efficient. Signed-off-by: fuyuanli <fuyuanli@didiglobal.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-03-07tcp: add tracing of skbaddr in tcp_event_skb classJason Xing
Use the existing parameter and print the address of skbaddr as other trace functions do. Signed-off-by: Jason Xing <kernelxing@tencent.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-03-07tcp: add tracing of skb/skaddr in tcp_event_sk_skb classJason Xing
Printing the addresses can help us identify the exact skb/sk for those system in which it's not that easy to run BPF program. As we can see, it already fetches those, then use it directly and it will print like below: ...tcp_retransmit_skb: skbaddr=XXX skaddr=XXX family=AF_INET... Signed-off-by: Jason Xing <kernelxing@tencent.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2023-08-09tcp: add missing family to tcp_set_ca_state() tracepointEric Dumazet
Before this code is copied, add the missing family, as we did in commit 3dd344ea84e1 ("net: tracepoint: exposing sk_family in all tcp:tracepoints") Fixes: 15fcdf6ae116 ("tcp: Add tracepoint for tcp_set_ca_state") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Ping Gan <jacky_gam_2001@163.com> Cc: Manjusaka <me@manjusaka.me> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://lore.kernel.org/r/20230808084923.2239142-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-03-17inet: preserve const qualifier in inet_sk()Eric Dumazet
We can change inet_sk() to propagate const qualifier of its argument. This should avoid some potential errors caused by accidental (const -> not_const) promotion. Other helpers like tcp_sk(), udp_sk(), raw_sk() will be handled in separate patch series. v2: use container_of_const() as advised by Jakub and Linus Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/netdev/20230315142841.3a2ac99a@kernel.org/ Link: https://lore.kernel.org/netdev/CAHk-=wiOf12nrYEF2vJMcucKjWPN-Ns_SW9fA7LwST_2Dzp7rw@mail.gmail.com/ Signed-off-by: David S. Miller <davem@davemloft.net>
2022-04-07tcp: Add tracepoint for tcp_set_ca_statePing Gan
The congestion status of a tcp flow may be updated since there is congestion between tcp sender and receiver. It makes sense to add tracepoint for congestion status set function to summate cc status duration and evaluate the performance of network and congestion algorithm. the backgound of this patch is below. Link: https://github.com/iovisor/bcc/pull/3899 Signed-off-by: Ping Gan <jacky_gam_2001@163.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20220406010956.19656-1-jacky_gam_2001@163.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-06tcp: add accessors to read/set tp->snd_cwndEric Dumazet
We had various bugs over the years with code breaking the assumption that tp->snd_cwnd is greater than zero. Lately, syzbot reported the WARN_ON_ONCE(!tp->prior_cwnd) added in commit 8b8a321ff72c ("tcp: fix zero cwnd in tcp_cwnd_reduction") can trigger, and without a repro we would have to spend considerable time finding the bug. Instead of complaining too late, we want to catch where and when tp->snd_cwnd is set to an illegal value. Signed-off-by: Eric Dumazet <edumazet@google.com> Suggested-by: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Link: https://lore.kernel.org/r/20220405233538.947344-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-05-14tcp: add tracepoint for checksum errorsJakub Kicinski
Add a tracepoint for capturing TCP segments with a bad checksum. This makes it easy to identify sources of bad frames in the fleet (e.g. machines with faulty NICs). It should also help tools like IOvisor's tcpdrop.py which are used today to get detailed information about such packets. We don't have a socket in many cases so we must open code the address extraction based just on the skb. v2: add missing export for ipv6=m Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-02-04net: tracepoint: exposing sk_family in all tcp:tracepointsHariharan Ananthakrishnan
Similar to sock:inet_sock_set_state tracepoint, expose sk_family to distinguish AF_INET and AF_INET6 families. The following tcp tracepoints are updated: tcp:tcp_destroy_sock tcp:tcp_rcv_space_adjust tcp:tcp_retransmit_skb tcp:tcp_send_reset tcp:tcp_receive_reset tcp:tcp_retransmit_synack tcp:tcp_probe Signed-off-by: Hariharan Ananthakrishnan <hari@netflix.com> Signed-off-by: Brendan Gregg <bgregg@netflix.com> Link: https://lore.kernel.org/r/20210129001210.344438-1-hari@netflix.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2019-11-09tcp: remove redundant new line from tcp_event_sk_skbTony Lu
This removes '\n' from trace event class tcp_event_sk_skb to avoid redundant new blank line and make output compact. Fixes: af4325ecc24f ("tcp: expose sk_state in tcp_retransmit_skb tracepoint") Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-26tcp: expose sk_state in tcp_retransmit_skb tracepointYafang Shao
After sk_state exposed, we can get in which state this retransmission occurs. That could give us more detail for dignostic. For example, if this retransmission occurs in SYN_SENT state, it may also indicates that the syn packet may be dropped on the remote peer due to syn backlog queue full and then we could check the remote peer. BTW,SYNACK retransmission is traced in tcp_retransmit_synack tracepoint. Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-31tcp: minor optimization around tcp_hdr() usage in receive pathYafang Shao
This is additional to the commit ea1627c20c34 ("tcp: minor optimizations around tcp_hdr() usage"). At this point, skb->data is same with tcp_hdr() as tcp header has not been pulled yet. So use the less expensive one to get the tcp header. Remove the third parameter of tcp_rcv_established() and put it into the function body. Furthermore, the local variables are listed as a reverse christmas tree :) Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-29tcp: use data length instead of skb->len in tcp_probeYafang Shao
skb->len is meaningless to user. data length could be more helpful, with which we can easily filter out the packet without payload. Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-23net: introduce a new tracepoint for tcp_rcv_space_adjustYafang Shao
tcp_rcv_space_adjust is called every time data is copied to user space, introducing a tcp tracepoint for which could show us when the packet is copied to user. When a tcp packet arrives, tcp_rcv_established() will be called and with the existed tracepoint tcp_probe we could get the time when this packet arrives. Then this packet will be copied to user, and tcp_rcv_space_adjust will be called and with this new introduced tracepoint we could get the time when this packet is copied to user. With these two tracepoints, we could figure out whether the user program processes this packet immediately or there's latency. Hence in the printk message, sk_cookie is printed as a key to relate tcp_rcv_space_adjust with tcp_probe. Maybe we could export sockfd in this new tracepoint as well, then we could relate this new tracepoint with epoll/read/recv* tracepoints, and finally that could show us the whole lifespan of this packet. But we could also implement that with pid as these functions are executed in process context. Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16net: Remove unused tcp_set_state tracepointAndrey Ignatov
This tracepoint was replaced by inet_sock_set_state in 563e0bb and not used anywhere in the kernel anymore. Remove it. Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-02net: dccp: Add DCCP sendmsg trace eventMasami Hiramatsu
Add DCCP sendmsg trace event (dccp/dccp_probe) for replacing dccpprobe. User can trace this event via ftrace or perftools. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-02net: tcp: Add trace events for TCP congestion window tracingMasami Hiramatsu
This adds an event to trace TCP stat variables with slightly intrusive trace-event. This uses ftrace/perf event log buffer to trace those state, no needs to prepare own ring-buffer, nor custom user apps. User can use ftrace to trace this event as below; # cd /sys/kernel/debug/tracing # echo 1 > events/tcp/tcp_probe/enable (run workloads) # cat trace Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-29Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
net/ipv6/ip6_gre.c is a case of parallel adds. include/trace/events/tcp.h is a little bit more tricky. The removal of in-trace-macro ifdefs in 'net' paralleled with moving show_tcp_state_name and friends over to include/trace/events/sock.h in 'net-next'. Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-26tcp: Avoid preprocessor directives in tracepoint macro argsMat Martineau
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 <dsahern@gmail.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-20net: tracepoint: replace tcp_set_state tracepoint with inet_sock_set_state ↵Yafang Shao
tracepoint As sk_state is a common field for struct sock, so the state transition tracepoint should not be a TCP specific feature. Currently it traces all AF_INET state transition, so I rename this tracepoint to inet_sock_set_state tracepoint with some minor changes and move it into trace/events/sock.h. We dont need to create a file named trace/events/inet_sock.h for this one single tracepoint. Two helpers are introduced to trace sk_state transition - void inet_sk_state_store(struct sock *sk, int newstate); - void inet_sk_set_state(struct sock *sk, int state); As trace header should not be included in other header files, so they are defined in sock.c. The protocol such as SCTP maybe compiled as a ko, hence export inet_sk_set_state(). Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-20tcp: Export to userspace the TCP state names for the trace eventsSteven Rostedt (VMware)
The TCP trace events (specifically tcp_set_state), maps emums to symbol names via __print_symbolic(). But this only works for reading trace events from the tracefs trace files. If perf or trace-cmd were to record these events, the event format file does not convert the enum names into numbers, and you get something like: __print_symbolic(REC->oldstate, { TCP_ESTABLISHED, "TCP_ESTABLISHED" }, { TCP_SYN_SENT, "TCP_SYN_SENT" }, { TCP_SYN_RECV, "TCP_SYN_RECV" }, { TCP_FIN_WAIT1, "TCP_FIN_WAIT1" }, { TCP_FIN_WAIT2, "TCP_FIN_WAIT2" }, { TCP_TIME_WAIT, "TCP_TIME_WAIT" }, { TCP_CLOSE, "TCP_CLOSE" }, { TCP_CLOSE_WAIT, "TCP_CLOSE_WAIT" }, { TCP_LAST_ACK, "TCP_LAST_ACK" }, { TCP_LISTEN, "TCP_LISTEN" }, { TCP_CLOSING, "TCP_CLOSING" }, { TCP_NEW_SYN_RECV, "TCP_NEW_SYN_RECV" }) Where trace-cmd and perf do not know the values of those enums. Use the TRACE_DEFINE_ENUM() macros that will have the trace events convert the enum strings into their values at system boot. This will allow perf and trace-cmd to see actual numbers and not enums: __print_symbolic(REC->oldstate, { 1, "TCP_ESTABLISHED" }, { 2, "TCP_SYN_SENT" }, { 3, "TCP_SYN_RECV" }, { 4, "TCP_FIN_WAIT1" }, { 5, "TCP_FIN_WAIT2" }, { 6, "TCP_TIME_WAIT" }, { 7, "TCP_CLOSE" }, { 8, "TCP_CLOSE_WAIT" }, { 9, "TCP_LAST_ACK" }, { 10, "TCP_LISTEN" }, { 11, "TCP_CLOSING" }, { 12, "TCP_NEW_SYN_RECV" }) Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-03tcp: add tracepoint trace_tcp_retransmit_synack()Song Liu
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 <songliubraving@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-24tcp: add tracepoint trace_tcp_set_state()Song Liu
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 <songliubraving@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-24tcp: add tracepoint trace_tcp_destroy_sockSong Liu
This patch adds trace event trace_tcp_destroy_sock. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-24tcp: add tracepoint trace_tcp_receive_resetSong Liu
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 <songliubraving@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-24tcp: add tracepoint trace_tcp_send_resetSong Liu
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 <songliubraving@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-24tcp: mark trace event arguments sk and skb as constSong Liu
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 <songliubraving@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-24tcp: add trace event class tcp_event_sk_skbSong Liu
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 <songliubraving@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-20tcp: Remove use of inet6_sk and add IPv6 checks to tracepointDavid Ahern
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 <dsahern@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Tested-by: Song Liu <songliubraving@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-18tcp: Check daddr_cache before use in tracepointDavid Ahern
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>
2017-10-18tcp: Use pI6c in tcp tracepointDavid Ahern
The compact form for IPv6 addresses is more user friendly than the full version. For example: compact: 2001:db8:1::1 full: 2001:0db8:0001:0000:0000:0000:0000:0004i Update the tcp tracepoint to show the compact form. Signed-off-by: David Ahern <dsahern@gmail.com> Acked-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-14tcp: add a tracepoint for tcp retransmissionCong Wang
We need a real-time notification for tcp retransmission for monitoring. Of course we could use ftrace to dynamically instrument this kernel function too, however we can't retrieve the connection information at the same time, for example perf-tools [1] reads /proc/net/tcp for socket details, which is slow when we have a lots of connections. Therefore, this patch adds a tracepoint for __tcp_retransmit_skb() and exposes src/dst IP addresses and ports of the connection. This also makes it easier to integrate into perf. Note, I expose both IPv4 and IPv6 addresses at the same time: for a IPv4 socket, v4 mapped address is used as IPv6 addresses, for a IPv6 socket, LOOPBACK4_IPV6 is already filled by kernel. Also, add sk and skb pointers as they are useful for BPF. 1. https://github.com/brendangregg/perf-tools/blob/master/net/tcpretrans Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Neal Cardwell <ncardwell@google.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Brendan Gregg <bgregg@netflix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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