Merge tag 'trace-v4.17-rc5-vsprintf' of... (9d38cd06) · Commits · 戴 / test

lib/vsprintf.c

+15 −11

Original line number	Diff line number	Diff line
		@@ -1669,19 +1669,22 @@ char pointer_string(char buf, char end, const void ptr,
		return number(buf, end, (unsigned long int)ptr, spec);
		}

		static bool have_filled_random_ptr_key __read_mostly;
		static DEFINE_STATIC_KEY_TRUE(not_filled_random_ptr_key);
		static siphash_key_t ptr_key __read_mostly;

		static void fill_random_ptr_key(struct random_ready_callback *unused)
		static void enable_ptr_key_workfn(struct work_struct *work)
		{
		get_random_bytes(&ptr_key, sizeof(ptr_key));
		/*
		* have_filled_random_ptr_key==true is dependent on get_random_bytes().
		* ptr_to_id() needs to see have_filled_random_ptr_key==true
		* after get_random_bytes() returns.
		*/
		smp_mb();
		WRITE_ONCE(have_filled_random_ptr_key, true);
		/* Needs to run from preemptible context */
		static_branch_disable(&not_filled_random_ptr_key);
		}

		static DECLARE_WORK(enable_ptr_key_work, enable_ptr_key_workfn);

		static void fill_random_ptr_key(struct random_ready_callback *unused)
		{
		/* This may be in an interrupt handler. */
		queue_work(system_unbound_wq, &enable_ptr_key_work);
		}

		static struct random_ready_callback random_ready = {
		@@ -1695,7 +1698,8 @@ static int __init initialize_ptr_random(void)
		if (!ret) {
		return 0;
		} else if (ret == -EALREADY) {
		fill_random_ptr_key(&random_ready);
		/* This is in preemptible context */
		enable_ptr_key_workfn(&enable_ptr_key_work);
		return 0;
		}

		@@ -1709,7 +1713,7 @@ static char ptr_to_id(char buf, char end, void ptr, struct printf_spec spec)
		unsigned long hashval;
		const int default_width = 2 * sizeof(ptr);

		if (unlikely(!have_filled_random_ptr_key)) {
		if (static_branch_unlikely(&not_filled_random_ptr_key)) {
		spec.field_width = default_width;
		/* string length must be less than default_width */
		return string(buf, end, "(ptrval)", spec);

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