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| author | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2023-06-06 21:39:56 +0900 |
|---|---|---|
| committer | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2023-06-06 21:39:56 +0900 |
| commit | 18b1e870a49671745c31434b18bcfdd6f20cb6a1 (patch) | |
| tree | aaca1e495b446890a1eae7efcf5b1a51348ae2d6 /kernel/trace/trace_probe.h | |
| parent | b576e09701c7d045bbe5cd85d53e2f34426aa214 (diff) | |
| download | linux-18b1e870a49671745c31434b18bcfdd6f20cb6a1.tar.gz linux-18b1e870a49671745c31434b18bcfdd6f20cb6a1.tar.bz2 linux-18b1e870a49671745c31434b18bcfdd6f20cb6a1.zip | |
tracing/probes: Add $arg* meta argument for all function args
Add the '$arg*' meta fetch argument for function-entry probe events. This
will be expanded to the all arguments of the function and the tracepoint
using BTF function argument information.
e.g.
# echo 'p vfs_read $arg*' >> dynamic_events
# echo 'f vfs_write $arg*' >> dynamic_events
# echo 't sched_overutilized_tp $arg*' >> dynamic_events
# cat dynamic_events
p:kprobes/p_vfs_read_0 vfs_read file=file buf=buf count=count pos=pos
f:fprobes/vfs_write__entry vfs_write file=file buf=buf count=count pos=pos
t:tracepoints/sched_overutilized_tp sched_overutilized_tp rd=rd overutilized=overutilized
Also, single '$arg[0-9]*' will be converted to the BTF function argument.
NOTE: This seems like a wildcard, but a fake one at this moment. This
is just for telling user that this can be expanded to several arguments.
And it is not like other $-vars, you can not use this $arg* as a part of
fetch args, e.g. specifying name "foo=$arg*" and using it in dereferences
"+0($arg*)" will lead a parse error.
Link: https://lore.kernel.org/all/168507475126.913472.18329684401466211816.stgit@mhiramat.roam.corp.google.com/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Diffstat (limited to 'kernel/trace/trace_probe.h')
| -rw-r--r-- | kernel/trace/trace_probe.h | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 7af121996ce9..e7fa2f2ed01c 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -33,7 +33,9 @@ #define MAX_ARGSTR_LEN 63 #define MAX_ARRAY_LEN 64 #define MAX_ARG_NAME_LEN 32 +#define MAX_BTF_ARGS_LEN 128 #define MAX_STRING_SIZE PATH_MAX +#define MAX_ARG_BUF_LEN (MAX_TRACE_ARGS * MAX_ARG_NAME_LEN) /* Reserved field names */ #define FIELD_STRING_IP "__probe_ip" @@ -391,6 +393,9 @@ struct traceprobe_parse_context { extern int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *argv, struct traceprobe_parse_context *ctx); +const char **traceprobe_expand_meta_args(int argc, const char *argv[], + int *new_argc, char *buf, int bufsize, + struct traceprobe_parse_context *ctx); extern int traceprobe_update_arg(struct probe_arg *arg); extern void traceprobe_free_probe_arg(struct probe_arg *arg); @@ -485,7 +490,11 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call, C(NO_EP_FILTER, "No filter rule after 'if'"), \ C(NOSUP_BTFARG, "BTF is not available or not supported"), \ C(NO_BTFARG, "This variable is not found at this probe point"),\ - C(NO_BTF_ENTRY, "No BTF entry for this probe point"), + C(NO_BTF_ENTRY, "No BTF entry for this probe point"), \ + C(BAD_VAR_ARGS, "$arg* must be an independent parameter without name etc."),\ + C(NOFENTRY_ARGS, "$arg* can be used only on function entry"), \ + C(DOUBLE_ARGS, "$arg* can be used only once in the parameters"), \ + C(ARGS_2LONG, "$arg* failed because the argument list is too long"), #undef C #define C(a, b) TP_ERR_##a |