linux/kernel/trace/trace_eprobe.c, branch v6.0

tracing/eprobes: Have event probes be consistent with kprobes and uprobes

2022-08-21T19:56:08Z

Currently, if a symbol "@" is attempted to be used with an event probe (eprobes), it will cause a NULL pointer dereference crash. Both kprobes and uprobes can reference data other than the main registers. Such as immediate address, symbols and the current task name. Have eprobes do the same thing. For "comm", if "comm" is used and the event being attached to does not have the "comm" field, then make it the "$comm" that kprobes has. This is consistent to the way histograms and filters work. Link: https://lkml.kernel.org/r/20220820134401.136924220@goodmis.org Cc: stable@vger.kernel.org Cc: Ingo Molnar Cc: Andrew Morton Cc: Masami Hiramatsu Cc: Tzvetomir Stoyanov Cc: Tom Zanussi Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events") Signed-off-by: Steven Rostedt (Google)

tracing/eprobes: Fix reading of string fields

2022-08-21T19:56:08Z

Currently when an event probe (eprobe) hooks to a string field, it does not display it as a string, but instead as a number. This makes the field rather useless. Handle the different kinds of strings, dynamic, static, relational/dynamic etc. Now when a string field is used, the ":string" type can be used to display it: echo "e:sw sched/sched_switch comm=$next_comm:string" > dynamic_events Link: https://lkml.kernel.org/r/20220820134400.959640191@goodmis.org Cc: stable@vger.kernel.org Cc: Ingo Molnar Cc: Andrew Morton Cc: Tzvetomir Stoyanov Cc: Tom Zanussi Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events") Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google)

tracing: React to error return from traceprobe_parse_event_name()

2022-08-21T19:56:07Z

The function traceprobe_parse_event_name() may set the first two function arguments to a non-null value and still return -EINVAL to indicate an unsuccessful completion of the function. Hence, it is not sufficient to just check the result of the two function arguments for being not null, but the return value also needs to be checked. Commit 95c104c378dc ("tracing: Auto generate event name when creating a group of events") changed the error-return-value checking of the second traceprobe_parse_event_name() invocation in __trace_eprobe_create() and removed checking the return value to jump to the error handling case. Reinstate using the return value in the error-return-value checking. Link: https://lkml.kernel.org/r/20220811071734.20700-1-lukas.bulwahn@gmail.com Fixes: 95c104c378dc ("tracing: Auto generate event name when creating a group of events") Acked-by: Linyu Yuan Signed-off-by: Lukas Bulwahn Signed-off-by: Steven Rostedt (Google)

tracing/eprobe: Show syntax error logs in error_log file

2022-08-02T19:22:55Z

Show the syntax errors for event probes in error_log file as same as other dynamic events, so that user can understand what is the problem. Link: https://lkml.kernel.org/r/165932113556.2850673.3483079297896607612.stgit@devnote2 Signed-off-by: Masami Hiramatsu (Google) 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: eprobe: Remove duplicate is_good_name() operation

2022-07-24T23:11:17Z

traceprobe_parse_event_name() already validate SYSTEM and EVENT name, there is no need to call is_good_name() after it. Link: https://lore.kernel.org/all/1656296348-16111-3-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: eprobe: Add missing log index

2022-07-24T23:11:17Z

Add trace_probe_log_set_index(1) to allow report correct error if user input wrong SYSTEM.EVENT format. Link: https://lore.kernel.org/all/1656296348-16111-2-git-send-email-quic_linyyuan@quicinc.com/ Reviewed-by: Tom Zanussi Signed-off-by: Linyu Yuan Signed-off-by: Steven Rostedt (Google)

tracing: Remove check of list iterator against head past the loop body

2022-04-27T21:19:31Z

When list_for_each_entry() completes the iteration over the whole list without breaking the loop, the iterator value will be a bogus pointer computed based on the head element. While it is safe to use the pointer to determine if it was computed based on the head element, either with list_entry_is_head() or &pos->member == head, using the iterator variable after the loop should be avoided. In preparation to limit the scope of a list iterator to the list traversal loop, use a dedicated pointer to point to the found element [1]. Link: https://lkml.kernel.org/r/20220427170734.819891-5-jakobkoschel@gmail.com Cc: Ingo Molnar Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ Signed-off-by: Jakob Koschel Signed-off-by: Steven Rostedt (Google)

tracing: Have existing event_command.parse() implementations use helpers

2022-04-26T21:58:50Z

Simplify the existing event_command.parse() implementations by having them make use of the helper functions previously introduced. Link: https://lkml.kernel.org/r/b353e3427a81f9d3adafd98fd7d73e78a8209f43.1644010576.git.zanussi@kernel.org Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (Google)

tracing: Remove redundant trigger_ops params

2022-04-26T21:58:50Z

Since event_trigger_data contains the .ops trigger_ops field, there's no reason to pass the trigger_ops separately. Remove it as a param from functions whenever event_trigger_data is passed. Link: https://lkml.kernel.org/r/9856c9bc81bde57077f5b8d6f8faa47156c6354a.1644010575.git.zanussi@kernel.org Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (Google)