user/sven/linux.git/kernel/trace/trace_kprobe.c, branch v6.4.3

kernel/trace: extract common part in process_fetch_insn

2023-02-24T01:04:13Z

Each probe has an instance of process_fetch_insn respectively, but they have something in common. This patch aims to extract the common part into process_common_fetch_insn which can be shared by each probe, and they only need to focus on their special cases. Signed-off-by: Song Chen Suggested-by: Masami Hiramatsu Acked-by: Masami Hiramatsu Signed-off-by: Masami Hiramatsu

kernel/trace: Provide default impelentations defined in trace_probe_tmpl.h

2023-02-24T00:44:27Z

There are 6 function definitions in trace_probe_tmpl.h, they are: 1, fetch_store_strlen 2, fetch_store_string 3, fetch_store_strlen_user 4, fetch_store_string_user 5, probe_mem_read 6, probe_mem_read_user Every C file which includes trace_probe_tmpl.h has to implement them, otherwise it gets warnings and errors. However, some of them are identical, like kprobe and eprobe, as a result, there is a lot redundant code in those 2 files. This patch would like to provide default behaviors for those functions which kprobe and eprobe can share by just including trace_probe_kernel.h with trace_probe_tmpl.h together. It removes redundant code, increases readability, and more importantly, makes it easier to introduce a new feature based on trace probe (it's possible). Link: https://lore.kernel.org/all/1672382018-18347-1-git-send-email-chensong_2000@189.cn/ Signed-off-by: Song Chen Reported-by: kernel test robot Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google)

kernel/trace: Introduce trace_probe_print_args and use it in *probes

2023-02-24T00:44:15Z

print_probe_args is currently inplemented in trace_probe_tmpl.h and included by *probes, as a result, each probe has an identical copy. This patch will move it to trace_probe.c as an new API, each probe calls it to print their args in trace file. Link: https://lore.kernel.org/all/1672382000-18304-1-git-send-email-chensong_2000@189.cn/ Signed-off-by: Song Chen Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google)

trace/kprobe: remove duplicated calls of ring_buffer_event_data

2022-12-10T04:48:05Z

Function __kprobe_trace_func calls ring_buffer_event_data to get a ring buffer, however, it has been done in above call trace_event_buffer_reserve. So does __kretprobe_trace_func. This patch removes those duplicated calls. Link: https://lore.kernel.org/all/1666145478-4706-1-git-send-email-chensong_2000@189.cn/ Reviewed-by: Steven Rostedt (Google) Acked-by: Masami Hiramatsu (Google) Signed-off-by: Song Chen Signed-off-by: Masami Hiramatsu (Google)

tracing: Move duplicate code of trace_kprobe/eprobe.c into header

2022-10-12T17:50:00Z

The functions: fetch_store_strlen_user() fetch_store_strlen() fetch_store_string_user() fetch_store_string() are identical in both trace_kprobe.c and trace_eprobe.c. Move them into a new header file trace_probe_kernel.h to share it. This code will later be used by the synthetic events as well. Marked for stable as a fix for a crash in synthetic events requires it. Link: https://lkml.kernel.org/r/20221012104534.467668078@goodmis.org Cc: stable@vger.kernel.org Cc: Andrew Morton Cc: Tom Zanussi Acked-by: Masami Hiramatsu (Google) Reviewed-by: Tom Zanussi Fixes: bd82631d7ccdc ("tracing: Add support for dynamic strings to synthetic events") Signed-off-by: Steven Rostedt (Google)

tracing: Auto generate event name when creating a group of events

2022-07-24T23:11:17Z

Currently when creating a specific group of trace events, take kprobe event as example, the user must use the following format: p:GRP/EVENT [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS], which means user must enter EVENT name, one example is: echo 'p:usb_gadget/config_usb_cfg_link config_usb_cfg_link $arg1' >> kprobe_events It is not simple if there are too many entries because the event name is the same as symbol name. This change allows user to specify no EVENT name, format changed as: p:GRP/ [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] It will generate event name automatically and one example is: echo 'p:usb_gadget/ config_usb_cfg_link $arg1' >> kprobe_events. Link: https://lore.kernel.org/all/1656296348-16111-4-git-send-email-quic_linyyuan@quicinc.com/ Acked-by: Masami Hiramatsu (Google) Reviewed-by: Tom Zanussi Signed-off-by: Linyu Yuan Signed-off-by: Steven Rostedt (Google)

tracing/kprobes: Check whether get_kretprobe() returns NULL in kretprobe_dispatcher()

2022-06-17T21:40:06Z

There is a small chance that get_kretprobe(ri) returns NULL in kretprobe_dispatcher() when another CPU unregisters the kretprobe right after __kretprobe_trampoline_handler(). To avoid this issue, kretprobe_dispatcher() checks the get_kretprobe() return value again. And if it is NULL, it returns soon because that kretprobe is under unregistering process. This issue has been introduced when the kretprobe is decoupled from the struct kretprobe_instance by commit d741bf41d7c7 ("kprobes: Remove kretprobe hash"). Before that commit, the struct kretprob_instance::rp directly points the kretprobe and it is never be NULL. Link: https://lkml.kernel.org/r/165366693881.797669.16926184644089588731.stgit@devnote2 Reported-by: Yonghong Song Fixes: d741bf41d7c7 ("kprobes: Remove kretprobe hash") Cc: Peter Zijlstra Cc: Ingo Molnar Cc: bpf Cc: Kernel Team Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) Acked-by: Jiri Olsa Signed-off-by: Steven Rostedt (Google)

tracing: Use trace_create_file() to simplify creation of tracefs entries

2022-05-27T01:12:52Z

Creating tracefs entries with tracefs_create_file() followed by pr_warn() is tedious and repetitive, we can use trace_create_file() to simplify this process and make the code more readable. Link: https://lkml.kernel.org/r/20220114131052.534382-1-ytcoode@gmail.com Acked-by: Masami Hiramatsu (Google) Signed-off-by: Yuntao Wang Signed-off-by: Steven Rostedt (Google)

kprobes: Use rethook for kretprobe if possible

2022-03-29T02:38:09Z

Use rethook for kretprobe function return hooking if the arch sets CONFIG_HAVE_RETHOOK=y. In this case, CONFIG_KRETPROBE_ON_RETHOOK is set to 'y' automatically, and the kretprobe internal data fields switches to use rethook. If not, it continues to use kretprobe specific function return hooks. Suggested-by: Peter Zijlstra Signed-off-by: Masami Hiramatsu Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/164826162556.2455864.12255833167233452047.stgit@devnote2

tracing: Fix return value of __setup handlers

2022-03-04T18:46:13Z

__setup() handlers should generally return 1 to indicate that the boot options have been handled. Using invalid option values causes the entire kernel boot option string to be reported as Unknown and added to init's environment strings, polluting it. Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc6 kprobe_event=p,syscall_any,$arg1 trace_options=quiet trace_clock=jiffies", will be passed to user space. Run /sbin/init as init process with arguments: /sbin/init with environment: HOME=/ TERM=linux BOOT_IMAGE=/boot/bzImage-517rc6 kprobe_event=p,syscall_any,$arg1 trace_options=quiet trace_clock=jiffies Return 1 from the __setup() handlers so that init's environment is not polluted with kernel boot options. Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Link: https://lkml.kernel.org/r/20220303031744.32356-1-rdunlap@infradead.org Cc: stable@vger.kernel.org Fixes: 7bcfaf54f591 ("tracing: Add trace_options kernel command line parameter") Fixes: e1e232ca6b8f ("tracing: Add trace_clock= kernel parameter") Fixes: 970988e19eb0 ("tracing/kprobe: Add kprobe_event= boot parameter") Signed-off-by: Randy Dunlap Reported-by: Igor Zhbanov Acked-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (Google)