From 10d9dda426d684e98b17161f02f77894c6de9b60 Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Fri, 7 Nov 2025 01:52:15 +0900 Subject: tracing: tprobe-events: Fix to register tracepoint correctly Since __tracepoint_user_init() calls tracepoint_user_register() without initializing tuser->tpoint with given tracpoint, it does not register tracepoint stub function as callback correctly, and tprobe does not work. Initializing tuser->tpoint correctly before tracepoint_user_register() so that it sets up tracepoint callback. I confirmed below example works fine again. echo "t sched_switch preempt prev_pid=prev->pid next_pid=next->pid" > /sys/kernel/tracing/dynamic_events echo 1 > /sys/kernel/tracing/events/tracepoints/sched_switch/enable cat /sys/kernel/tracing/trace_pipe Link: https://lore.kernel.org/all/176244793514.155515.6466348656998627773.stgit@devnote2/ Fixes: 2867495dea86 ("tracing: tprobe-events: Register tracepoint when enable tprobe event") Reported-by: Beau Belgrave Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) Tested-by: Beau Belgrave Reviewed-by: Beau Belgrave --- kernel/trace/trace_fprobe.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel/trace/trace_fprobe.c') diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c index ad9d6347b5fa..fd1b108ab639 100644 --- a/kernel/trace/trace_fprobe.c +++ b/kernel/trace/trace_fprobe.c @@ -106,13 +106,14 @@ static struct tracepoint_user *__tracepoint_user_init(const char *name, struct t if (!tuser->name) return NULL; + /* Register tracepoint if it is loaded. */ if (tpoint) { + tuser->tpoint = tpoint; ret = tracepoint_user_register(tuser); if (ret) return ERR_PTR(ret); } - tuser->tpoint = tpoint; tuser->refcount = 1; INIT_LIST_HEAD(&tuser->list); list_add(&tuser->list, &tracepoint_user_list); -- cgit v1.2.3 From c91afa7610235f89a5e8f5686aac23892ab227ed Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Fri, 7 Nov 2025 01:52:24 +0900 Subject: tracing: tprobe-events: Fix to put tracepoint_user when disable the tprobe __unregister_trace_fprobe() checks tf->tuser to put it when removing tprobe. However, disable_trace_fprobe() does not use it and only calls unregister_fprobe(). Thus it forgets to disable tracepoint_user. If the trace_fprobe has tuser, put it for unregistering the tracepoint callbacks when disabling tprobe correctly. Link: https://lore.kernel.org/all/176244794466.155515.3971904050506100243.stgit@devnote2/ Fixes: 2867495dea86 ("tracing: tprobe-events: Register tracepoint when enable tprobe event") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) Tested-by: Beau Belgrave Reviewed-by: Beau Belgrave --- kernel/trace/trace_fprobe.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/trace/trace_fprobe.c') diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c index fd1b108ab639..8001dbf16891 100644 --- a/kernel/trace/trace_fprobe.c +++ b/kernel/trace/trace_fprobe.c @@ -1514,6 +1514,10 @@ static int disable_trace_fprobe(struct trace_event_call *call, if (!trace_probe_is_enabled(tp)) { list_for_each_entry(tf, trace_probe_probe_list(tp), tp.list) { unregister_fprobe(&tf->fp); + if (tf->tuser) { + tracepoint_user_put(tf->tuser); + tf->tuser = NULL; + } } } -- cgit v1.2.3