return widen_string(buf, buf - buf_start, end, spec);
}
- static noinline_for_stack
- char *pointer_string(char *buf, char *end, const void *ptr,
- struct printf_spec spec)
- {
- spec.base = 16;
- spec.flags |= SMALL;
- if (spec.field_width == -1) {
- spec.field_width = 2 * sizeof(ptr);
- spec.flags |= ZEROPAD;
- }
-
- 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(¬_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 = {
/* Maps a pointer to a 32 bit unique identifier. */
static char *ptr_to_id(char *buf, char *end, void *ptr, struct printf_spec spec)
{
+ const char *str = sizeof(ptr) == 8 ? "(____ptrval____)" : "(ptrval)";
unsigned long hashval;
- const int default_width = 2 * sizeof(ptr);
- if (unlikely(!have_filled_random_ptr_key)) {
+ if (static_branch_unlikely(¬_filled_random_ptr_key)) {
- spec.field_width = default_width;
+ spec.field_width = 2 * sizeof(ptr);
/* string length must be less than default_width */
- return string(buf, end, "(ptrval)", spec);
+ return string(buf, end, str, spec);
}
#ifdef CONFIG_64BIT