When trying to create kretprobe with the wrong function symbol in tracefs;
The error is triggered in the register_trace_kprobe() and recorded as
FAIL_REG_PROBE issue,
Example:
$ cd /sys/kernel/debug/tracing
$ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events
bash: echo: write error: Invalid argument
$ cat error_log
[142797.347877] trace_kprobe: error: Failed to register probe event
Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0
^
This error can be detected in the parameter parsing stage, the effect of
applying this patch is as follows:
$ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events
bash: echo: write error: Invalid argument
$ cat error_log
[415.89]trace_kprobe: error: Retprobe address must be an function entry
Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0
^
v2 changes:
- Added !strchr(symbol, ':') to check whether symbol is really bad
or from a module.
Signed-off-by: Jianlin Lv <jianlin...@arm.com>
---
v2: added !strchr(symbol, ':') to check really bad symbol or from module.
v4: added changelog and code comments.
---
kernel/trace/trace_kprobe.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index e6fba1798771..384208a38f82 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -830,7 +830,8 @@ static int trace_kprobe_create(int argc, const char *argv[])
flags |= TPARG_FL_RETURN;
if (kprobe_on_func_entry(NULL, symbol, offset))
flags |= TPARG_FL_FENTRY;
- if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
+ /* Check whether symbol is really bad or from a module */
+ if (!strchr(symbol, ':') && is_return && !(flags &
TPARG_FL_FENTRY)) {
trace_probe_log_err(0, BAD_RETPROBE);
goto parse_error;
}
--
2.25.1
