From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx> 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 45ab2813d40d88fc575e753c38478de242d03f88 upstream. If a module fails to add its tracepoints due to module tainting, do not create the module event infrastructure in the debugfs directory. As the events will not work and worse yet, they will silently fail, making the user wonder why the events they enable do not display anything. Having a warning on module load and the events not visible to the users will make the cause of the problem much clearer. Link: http://lkml.kernel.org/r/20140227154923.265882695@xxxxxxxxxxx Fixes: 6d723736e472 "tracing/events: add support for modules to TRACE_EVENT" Acked-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx> Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- include/linux/tracepoint.h | 6 ++++++ kernel/trace/trace_events.c | 10 ++++++++++ kernel/tracepoint.c | 7 ++++++- 3 files changed, 22 insertions(+), 1 deletion(-) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index ebeab360d851..0ecc46e7af3d 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -60,6 +60,12 @@ struct tp_module { unsigned int num_tracepoints; struct tracepoint * const *tracepoints_ptrs; }; +bool trace_module_has_bad_taint(struct module *mod); +#else +static inline bool trace_module_has_bad_taint(struct module *mod) +{ + return false; +} #endif /* CONFIG_MODULES */ struct tracepoint_iter { diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 368a4d50cc30..b03b1f897b5e 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1763,6 +1763,16 @@ static void trace_module_add_events(struct module *mod) { struct ftrace_event_call **call, **start, **end; + if (!mod->num_trace_events) + return; + + /* Don't add infrastructure for mods without tracepoints */ + if (trace_module_has_bad_taint(mod)) { + pr_err("%s: module has bad taint, not creating trace events\n", + mod->name); + return; + } + start = mod->trace_events; end = mod->trace_events + mod->num_trace_events; diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 29f26540e9c9..031cc5655a51 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -631,6 +631,11 @@ void tracepoint_iter_reset(struct tracepoint_iter *iter) EXPORT_SYMBOL_GPL(tracepoint_iter_reset); #ifdef CONFIG_MODULES +bool trace_module_has_bad_taint(struct module *mod) +{ + return mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP)); +} + static int tracepoint_module_coming(struct module *mod) { struct tp_module *tp_mod, *iter; @@ -641,7 +646,7 @@ static int tracepoint_module_coming(struct module *mod) * module headers (for forced load), to make sure we don't cause a crash. * Staging and out-of-tree GPL modules are fine. */ - if (mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP))) + if (trace_module_has_bad_taint(mod)) return 0; mutex_lock(&tracepoints_mutex); tp_mod = kmalloc(sizeof(struct tp_module), GFP_KERNEL); -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html