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 d5f30a7da8ea8e6450250275cec5670cee3c4264 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 d5f30a7da8ea8e6450250275cec5670cee3c4264 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/all/20221117214249.2addbe10@xxxxxxxxxxxxxxxxxx/ Cc: stable@xxxxxxxxxxxxxxx Fixes: 7491e2c442781 ("tracing: Add a probe that attaches to trace events") Reported-by: Rafael Mendonca <rafaelmendsr@xxxxxxxxx> Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> 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 @@ -563,6 +563,9 @@ static void eprobe_trigger_func(struct e if (unlikely(!rec)) return; + 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/tracing-fix-issue-of-missing-one-synthetic-field.patch queue-6.0/tracing-hist-fix-wrong-return-value-in-parse_action_params.patch queue-6.0/tracing-probes-handle-system-names-with-hyphens.patch queue-6.0/tracing-hist-fix-out-of-bound-write-on-action_data.var_ref_idx.patch queue-6.0/kest.pl-fix-grub2-menu-handling-for-rebooting.patch queue-6.0/ktest.pl-minconfig-unset-configs-instead-of-just-removing-them.patch queue-6.0/tracing-fix-complicated-dependency-of-config_tracer_max_trace.patch queue-6.0/tracing-fix-infinite-loop-in-tracing_read_pipe-on-overflowed-print_trace_line.patch queue-6.0/ftrace-x86-add-back-ftrace_expected-for-ftrace-bug-reports.patch