This is a note to let you know that I've just added the patch titled tracing: Fix race where eprobes can be called before the event to the 6.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tracing-fix-race-where-eprobes-can-be-called-before-the-event.patch and it can be found in the queue-6.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 94eedf3dded5fb472ce97bfaf3ac1c6c29c35d26 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx> Date: Thu, 17 Nov 2022 21:42:49 -0500 Subject: tracing: Fix race where eprobes can be called before the event From: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> commit 94eedf3dded5fb472ce97bfaf3ac1c6c29c35d26 upstream. The flag that tells the event to call its triggers after reading the event is set for eprobes after the eprobe is enabled. This leads to a race where the eprobe may be triggered at the beginning of the event where the record information is NULL. The eprobe then dereferences the NULL record causing a NULL kernel pointer bug. Test for a NULL record to keep this from happening. Link: https://lore.kernel.org/linux-trace-kernel/20221116192552.1066630-1-rafaelmendsr@xxxxxxxxx/ Link: https://lore.kernel.org/linux-trace-kernel/20221117214249.2addbe10@xxxxxxxxxxxxxxxxxx Cc: Linux Trace Kernel <linux-trace-kernel@xxxxxxxxxxxxxxx> Cc: Tzvetomir Stoyanov <tz.stoyanov@xxxxxxxxx> Cc: Tom Zanussi <zanussi@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Fixes: 7491e2c442781 ("tracing: Add a probe that attaches to trace events") Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> Reported-by: Rafael Mendonca <rafaelmendsr@xxxxxxxxx> Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/trace/trace_eprobe.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -560,6 +560,9 @@ static void eprobe_trigger_func(struct e { struct eprobe_data *edata = data->private_data; + if (unlikely(!rec)) + return; + __eprobe_trace_func(edata, rec); } Patches currently in stable-queue which might be from rostedt@xxxxxxxxxxx are queue-6.0/tracing-fix-race-where-eprobes-can-be-called-before-the-event.patch queue-6.0/ftrace-fix-null-pointer-dereference-in-ftrace_add_mod.patch queue-6.0/tracing-fix-memory-leak-in-tracing_read_pipe.patch queue-6.0/tracing-ring-buffer-have-polling-block-on-watermark.patch queue-6.0/ftrace-optimize-the-allocation-for-mcount-entries.patch queue-6.0/ring_buffer-do-not-deactivate-non-existant-pages.patch queue-6.0/ftrace-fix-the-possible-incorrect-kernel-message.patch queue-6.0/tracing-fix-memory-leak-in-test_gen_synth_cmd-and-test_empty_synth_event.patch queue-6.0/tracing-fix-wild-memory-access-in-register_synth_event.patch