Hi,
On 25/08/2024 09:41, Masami Hiramatsu (Google) wrote:
Hi,
On Tue, 13 Aug 2024 13:25:40 -0400
Fernando Fernandez Mancera <[email protected]> wrote:
When initializing trace_probes::nr_args, make sure the maximum number of
probe arguments is honored. Oherwise, we can hit a NULL pointer
dereferences in multiple situations like on traceprobe_set_print_fmt().
Link: https://bugzilla.redhat.com/2303876
Sorry for replying later. I'm not sure why but I did not found this in my
mbox...
No worries!
Anyway, trace_probe_init() should return -E2BIG in this case because
it is actuall wrong value.
Can you update your patch?
I agree this is the right solution but it would mean a change in
behavior. Is that fine? Before merging 035ba76014c0, it was writing up
to the maximum number of arguments and ignoring the rest. If you confirm
it is fine to change the behavior, I will update the patch.
Thank you!
Thank you,
Fixes: 035ba76014c0 ("tracing/probes: cleanup: Set trace_probe::nr_args at
trace_probe_init")
Signed-off-by: Fernando Fernandez Mancera <[email protected]>
---
kernel/trace/trace_probe.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 39877c80d6cb..f577b5e71026 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -2043,10 +2043,14 @@ int trace_probe_init(struct trace_probe *tp, const char
*event,
goto error;
}
- tp->nr_args = nargs;
+ if (nargs > MAX_TRACE_ARGS)
+ tp->nr_args = MAX_TRACE_ARGS;
+ else
+ tp->nr_args = nargs;
+
/* Make sure pointers in args[] are NULL */
if (nargs)
- memset(tp->args, 0, sizeof(tp->args[0]) * nargs);
+ memset(tp->args, 0, sizeof(tp->args[0]) * tp->nr_args);
return 0;
