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| author | Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-08-20 09:43:19 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-08-25 11:40:28 +0200 |
| commit | 1c7e569c0eceb9977017952c1892b71c8903ec9d (patch) | |
| tree | d4fa6f04586b80c5af41a47789532ed1fba78c2e /kernel | |
| parent | 830426469f773f69be65f609841a0c2970a7d677 (diff) | |
| download | linux-1c7e569c0eceb9977017952c1892b71c8903ec9d.tar.gz linux-1c7e569c0eceb9977017952c1892b71c8903ec9d.tar.bz2 linux-1c7e569c0eceb9977017952c1892b71c8903ec9d.zip | |
tracing/eprobes: Fix reading of string fields
commit f04dec93466a0481763f3b56cdadf8076e28bfbf upstream.
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 <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace_eprobe.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c index 815c02855dab..32688357c6da 100644 --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -320,6 +320,24 @@ static unsigned long get_event_field(struct fetch_insn *code, void *rec) addr = rec + field->offset; + if (is_string_field(field)) { + switch (field->filter_type) { + case FILTER_DYN_STRING: + val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff)); + break; + case FILTER_STATIC_STRING: + val = (unsigned long)addr; + break; + case FILTER_PTR_STRING: + val = (unsigned long)(*(char *)addr); + break; + default: + WARN_ON_ONCE(1); + return 0; + } + return val; + } + switch (field->size) { case 1: if (field->is_signed) |