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Diffstat (limited to 'lib/vsprintf.c')
-rw-r--r--lib/vsprintf.c66
1 files changed, 22 insertions, 44 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 20e9887faaaa..fb77f7bfd126 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -750,60 +750,38 @@ static int __init debug_boot_weak_hash_enable(char *str)
}
early_param("debug_boot_weak_hash", debug_boot_weak_hash_enable);
-static DEFINE_STATIC_KEY_TRUE(not_filled_random_ptr_key);
-static siphash_key_t ptr_key __read_mostly;
+static DEFINE_STATIC_KEY_FALSE(filled_random_ptr_key);
static void enable_ptr_key_workfn(struct work_struct *work)
{
- get_random_bytes(&ptr_key, sizeof(ptr_key));
- /* Needs to run from preemptible context */
- static_branch_disable(&not_filled_random_ptr_key);
+ static_branch_enable(&filled_random_ptr_key);
}
-static DECLARE_WORK(enable_ptr_key_work, enable_ptr_key_workfn);
-
-static int fill_random_ptr_key(struct notifier_block *nb,
- unsigned long action, void *data)
-{
- /* This may be in an interrupt handler. */
- queue_work(system_unbound_wq, &enable_ptr_key_work);
- return 0;
-}
-
-static struct notifier_block random_ready = {
- .notifier_call = fill_random_ptr_key
-};
-
-static int __init initialize_ptr_random(void)
-{
- int ret;
-
- /* Don't bother waiting for RNG to be ready if RDRAND is mixed in already. */
- if (rng_has_arch_random()) {
- enable_ptr_key_workfn(&enable_ptr_key_work);
- return 0;
- }
-
- ret = register_random_ready_notifier(&random_ready);
- if (!ret) {
- return 0;
- } else if (ret == -EALREADY) {
- /* This is in preemptible context */
- enable_ptr_key_workfn(&enable_ptr_key_work);
- return 0;
- }
-
- return ret;
-}
-early_initcall(initialize_ptr_random);
-
/* Maps a pointer to a 32 bit unique identifier. */
static inline int __ptr_to_hashval(const void *ptr, unsigned long *hashval_out)
{
+ static siphash_key_t ptr_key __read_mostly;
unsigned long hashval;
- if (static_branch_unlikely(&not_filled_random_ptr_key))
- return -EAGAIN;
+ if (!static_branch_likely(&filled_random_ptr_key)) {
+ static bool filled = false;
+ static DEFINE_SPINLOCK(filling);
+ static DECLARE_WORK(enable_ptr_key_work, enable_ptr_key_workfn);
+ unsigned long flags;
+
+ if (!system_unbound_wq ||
+ (!rng_is_initialized() && !rng_has_arch_random()) ||
+ !spin_trylock_irqsave(&filling, flags))
+ return -EAGAIN;
+
+ if (!filled) {
+ get_random_bytes(&ptr_key, sizeof(ptr_key));
+ queue_work(system_unbound_wq, &enable_ptr_key_work);
+ filled = true;
+ }
+ spin_unlock_irqrestore(&filling, flags);
+ }
+
#ifdef CONFIG_64BIT
hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key);