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tracing/fprobe-event: Assume fprobe is a return event by $retval 

Assume the fprobe event is a return event if there is $retval is
used in the probe's argument without %return. e.g.

echo 'f:myevent vfs_read $retval' >> dynamic_events

then 'myevent' is a return probe event.

Link: https://lore.kernel.org/all/169272160261.160970.13613040161560998787.stgit@devnote2/

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu (Google) 2023-08-23 01:26:42 +09:00
parent 27973e5c64
commit 08c9306fc2
2 changed files with 45 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
kernel/trace/trace_fprobe.c
View File

@ -898,6 +898,46 @@ static struct tracepoint *find_tracepoint(const char *tp_name)
return data.tpoint;
}
static int parse_symbol_and_return(int argc, const char *argv[],
char **symbol, bool *is_return,
bool is_tracepoint)
{
char *tmp = strchr(argv[1], '%');
int i;
if (tmp) {
int len = tmp - argv[1];
if (!is_tracepoint && !strcmp(tmp, "%return")) {
*is_return = true;
} else {
trace_probe_log_err(len, BAD_ADDR_SUFFIX);
return -EINVAL;
}
*symbol = kmemdup_nul(argv[1], len, GFP_KERNEL);
} else
*symbol = kstrdup(argv[1], GFP_KERNEL);
if (!*symbol)
return -ENOMEM;
if (*is_return)
return 0;
/* If there is $retval, this should be a return fprobe. */
for (i = 2; i < argc; i++) {
tmp = strstr(argv[i], "$retval");
if (tmp && !isalnum(tmp[7]) && tmp[7] != '_') {
*is_return = true;
/*
* NOTE: Don't check is_tracepoint here, because it will
* be checked when the argument is parsed.
*/
break;
}
}
return 0;
}
static int __trace_fprobe_create(int argc, const char *argv[])
{
/*
@ -927,7 +967,7 @@ static int __trace_fprobe_create(int argc, const char *argv[])
struct trace_fprobe *tf = NULL;
int i, len, new_argc = 0, ret = 0;
bool is_return = false;
char *symbol = NULL, *tmp = NULL;
char *symbol = NULL;
const char *event = NULL, *group = FPROBE_EVENT_SYSTEM;
const char **new_argv = NULL;
int maxactive = 0;
@ -983,20 +1023,10 @@ static int __trace_fprobe_create(int argc, const char *argv[])
trace_probe_log_set_index(1);
/* a symbol(or tracepoint) must be specified */
symbol = kstrdup(argv[1], GFP_KERNEL);
if (!symbol)
return -ENOMEM;
tmp = strchr(symbol, '%');
if (tmp) {
if (!is_tracepoint && !strcmp(tmp, "%return")) {
*tmp = '\0';
is_return = true;
} else {
trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
ret = parse_symbol_and_return(argc, argv, &symbol, &is_return, is_tracepoint);
if (ret < 0)
goto parse_error;
}
}
if (!is_return && maxactive) {
trace_probe_log_set_index(0);
trace_probe_log_err(1, BAD_MAXACT_TYPE);

2
tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
View File

@ -30,11 +30,11 @@ check_error 'f:^ vfs_read' # NO_EVENT_NAME
check_error 'f:foo/^12345678901234567890123456789012345678901234567890123456789012345 vfs_read' # EVENT_TOO_LONG
check_error 'f:foo/^bar.1 vfs_read' # BAD_EVENT_NAME
check_error 'f vfs_read ^$retval' # RETVAL_ON_PROBE
check_error 'f vfs_read ^$stack10000' # BAD_STACK_NUM
check_error 'f vfs_read ^$arg10000' # BAD_ARG_NUM
check_error 'f vfs_read $retval ^$arg1' # BAD_VAR
check_error 'f vfs_read ^$none_var' # BAD_VAR
check_error 'f vfs_read ^'$REG # BAD_VAR