tracepoints: Prevent null probe from being added (4c69e6ea) · Commits · 戴 / test

Somehow tracepoint_entry_add_probe() function allows a null probe function. And, this may lead to unexpected results since the number of probe functions in an entry can be counted by checking whether a probe is null or not in the for-loop. This patch prevents a null probe from being added. In tracepoint_entry_remove_probe() function, checking probe parameter within the for-loop is moved out for code efficiency, leaving the null probe feature which removes all probe functions in the entry. Link: http://lkml.kernel.org/r/1365991995-19445-1-git-send-email-kpark3469@gmail.com Reviewed-by:

Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by:

Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by:

Sahara <keun-o.park@windriver.com> Signed-off-by:

Steven Rostedt <rostedt@goodmis.org>

kernel/tracepoint.c

+13 −8

Original line number	Diff line number	Diff line
		@@ -112,7 +112,8 @@ tracepoint_entry_add_probe(struct tracepoint_entry *entry,
		int nr_probes = 0;
		struct tracepoint_func old, new;

		WARN_ON(!probe);
		if (WARN_ON(!probe))
		return ERR_PTR(-EINVAL);

		debug_print_probes(entry);
		old = entry->funcs;
		@@ -152,13 +153,18 @@ tracepoint_entry_remove_probe(struct tracepoint_entry *entry,

		debug_print_probes(entry);
		/* (N -> M), (N > 1, M >= 0) probes */
		if (probe) {
		for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
		if (!probe \|\|
		(old[nr_probes].func == probe &&
		old[nr_probes].data == data))
		if (old[nr_probes].func == probe &&
		old[nr_probes].data == data)
		nr_del++;
		}
		}

		/*
		* If probe is NULL, then nr_probes = nr_del = 0, and then the
		* entire entry will be removed.
		*/
		if (nr_probes - nr_del == 0) {
		/* N -> 0, (N > 1) */
		entry->funcs = NULL;
		@@ -173,8 +179,7 @@ tracepoint_entry_remove_probe(struct tracepoint_entry *entry,
		if (new == NULL)
		return ERR_PTR(-ENOMEM);
		for (i = 0; old[i].func; i++)
		if (probe &&
		(old[i].func != probe \|\| old[i].data != data))
		if (old[i].func != probe \|\| old[i].data != data)
		new[j++] = old[i];
		new[nr_probes - nr_del].func = NULL;
		entry->refcount = nr_probes - nr_del;

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