Commit b61387cb authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (VMware)
Browse files

tracing/uprobe: Fix to make trace_uprobe_filter alignment safe 

Commit 99c9a923 ("tracing/uprobe: Fix double perf_event
linking on multiprobe uprobe") moved trace_uprobe_filter on
trace_probe_event. However, since it introduced a flexible
data structure with char array and type casting, the
alignment of trace_uprobe_filter can be broken.

This changes the type of the array to trace_uprobe_filter
data strucure to fix it.

Link: http://lore.kernel.org/r/20200120124022.GA14897@hirez.programming.kicks-ass.net
Link: http://lkml.kernel.org/r/157966340499.5107.10978352478952144902.stgit@devnote2



Fixes: 99c9a923 ("tracing/uprobe: Fix double perf_event linking on multiprobe uprobe")
Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent bf24daac

kernel/trace/trace_kprobe.c

+1 −1
Original line number Diff line number Diff line
@@ -290,7 +290,7 @@ static struct trace_kprobe *alloc_trace_kprobe(const char *group, 
	INIT_HLIST_NODE(&tk->rp.kp.hlist);

	INIT_LIST_HEAD(&tk->rp.kp.list);



	ret = trace_probe_init(&tk->tp, event, group, 0);

	ret = trace_probe_init(&tk->tp, event, group, false);

	if (ret < 0)

		goto error;

kernel/trace/trace_probe.c

+6 −3
Original line number Diff line number Diff line
@@ -984,16 +984,19 @@ void trace_probe_cleanup(struct trace_probe *tp) 
}



int trace_probe_init(struct trace_probe *tp, const char *event,

		     const char *group, size_t event_data_size)

		     const char *group, bool alloc_filter)

{

	struct trace_event_call *call;

	size_t size = sizeof(struct trace_probe_event);

	int ret = 0;



	if (!event || !group)

		return -EINVAL;



	tp->event = kzalloc(sizeof(struct trace_probe_event) + event_data_size,

			    GFP_KERNEL);

	if (alloc_filter)

		size += sizeof(struct trace_uprobe_filter);



	tp->event = kzalloc(size, GFP_KERNEL);

	if (!tp->event)

		return -ENOMEM;

kernel/trace/trace_probe.h

+8 −2
Original line number Diff line number Diff line
@@ -223,6 +223,12 @@ struct probe_arg { 
	const struct fetch_type	*type;	/* Type of this argument */

};



struct trace_uprobe_filter {

	rwlock_t		rwlock;

	int			nr_systemwide;

	struct list_head	perf_events;

};



/* Event call and class holder */

struct trace_probe_event {

	unsigned int			flags;	/* For TP_FLAG_* */
@@ -230,7 +236,7 @@ struct trace_probe_event { 
	struct trace_event_call		call;

	struct list_head 		files;

	struct list_head		probes;

	char				data[0];

	struct trace_uprobe_filter	filter[0];

};



struct trace_probe {
@@ -323,7 +329,7 @@ static inline bool trace_probe_has_single_file(struct trace_probe *tp) 
}



int trace_probe_init(struct trace_probe *tp, const char *event,

		     const char *group, size_t event_data_size);

		     const char *group, bool alloc_filter);

void trace_probe_cleanup(struct trace_probe *tp);

int trace_probe_append(struct trace_probe *tp, struct trace_probe *to);

void trace_probe_unlink(struct trace_probe *tp);

kernel/trace/trace_uprobe.c

+7 −22
Original line number Diff line number Diff line
@@ -34,12 +34,6 @@ struct uprobe_trace_entry_head { 
#define DATAOF_TRACE_ENTRY(entry, is_return)		\

	((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))



struct trace_uprobe_filter {

	rwlock_t		rwlock;

	int			nr_systemwide;

	struct list_head	perf_events;

};



static int trace_uprobe_create(int argc, const char **argv);

static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev);

static int trace_uprobe_release(struct dyn_event *ev);
@@ -263,14 +257,6 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 
}

NOKPROBE_SYMBOL(process_fetch_insn)



static struct trace_uprobe_filter *

trace_uprobe_get_filter(struct trace_uprobe *tu)

{

	struct trace_probe_event *event = tu->tp.event;



	return (struct trace_uprobe_filter *)&event->data[0];

}



static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)

{

	rwlock_init(&filter->rwlock);
@@ -358,8 +344,7 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) 
	if (!tu)

		return ERR_PTR(-ENOMEM);



	ret = trace_probe_init(&tu->tp, event, group,

				sizeof(struct trace_uprobe_filter));

	ret = trace_probe_init(&tu->tp, event, group, true);

	if (ret < 0)

		goto error;
@@ -367,7 +352,7 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) 
	tu->consumer.handler = uprobe_dispatcher;

	if (is_ret)

		tu->consumer.ret_handler = uretprobe_dispatcher;

	init_trace_uprobe_filter(trace_uprobe_get_filter(tu));

	init_trace_uprobe_filter(tu->tp.event->filter);

	return tu;



error:
@@ -1076,7 +1061,7 @@ static void __probe_event_disable(struct trace_probe *tp) 
	struct trace_uprobe *tu;



	tu = container_of(tp, struct trace_uprobe, tp);

	WARN_ON(!uprobe_filter_is_empty(trace_uprobe_get_filter(tu)));

	WARN_ON(!uprobe_filter_is_empty(tu->tp.event->filter));



	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {

		tu = container_of(pos, struct trace_uprobe, tp);
@@ -1117,7 +1102,7 @@ static int probe_event_enable(struct trace_event_call *call, 
	}



	tu = container_of(tp, struct trace_uprobe, tp);

	WARN_ON(!uprobe_filter_is_empty(trace_uprobe_get_filter(tu)));

	WARN_ON(!uprobe_filter_is_empty(tu->tp.event->filter));



	if (enabled)

		return 0;
@@ -1281,7 +1266,7 @@ static int uprobe_perf_close(struct trace_event_call *call, 
		return -ENODEV;



	tu = container_of(tp, struct trace_uprobe, tp);

	if (trace_uprobe_filter_remove(trace_uprobe_get_filter(tu), event))

	if (trace_uprobe_filter_remove(tu->tp.event->filter, event))

		return 0;



	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
@@ -1306,7 +1291,7 @@ static int uprobe_perf_open(struct trace_event_call *call, 
		return -ENODEV;



	tu = container_of(tp, struct trace_uprobe, tp);

	if (trace_uprobe_filter_add(trace_uprobe_get_filter(tu), event))

	if (trace_uprobe_filter_add(tu->tp.event->filter, event))

		return 0;



	list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
@@ -1328,7 +1313,7 @@ static bool uprobe_perf_filter(struct uprobe_consumer *uc, 
	int ret;



	tu = container_of(uc, struct trace_uprobe, consumer);

	filter = trace_uprobe_get_filter(tu);

	filter = tu->tp.event->filter;



	read_lock(&filter->rwlock);

	ret = __uprobe_perf_filter(filter, mm);

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