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Merge branch 'for-6.1-hash-pointer-init' into for-linus

This commit is contained in:
Petr Mladek 2022-10-04 15:55:44 +02:00
parent dc453dd89d 6f0ac3b52a
commit da743a92e5
1 changed files with 26 additions and 21 deletions
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47
lib/vsprintf.c
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@ -750,37 +750,42 @@ 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_FALSE(filled_random_ptr_key);
static bool filled_random_ptr_key __read_mostly;
static siphash_key_t ptr_key __read_mostly;
static void fill_ptr_key_workfn(struct work_struct *work);
static DECLARE_DELAYED_WORK(fill_ptr_key_work, fill_ptr_key_workfn);
static void enable_ptr_key_workfn(struct work_struct *work)
static void fill_ptr_key_workfn(struct work_struct *work)
{
static_branch_enable(&filled_random_ptr_key);
if (!rng_is_initialized()) {
queue_delayed_work(system_unbound_wq, &fill_ptr_key_work, HZ * 2);
return;
}
get_random_bytes(&ptr_key, sizeof(ptr_key));
/* Pairs with smp_rmb() before reading ptr_key. */
smp_wmb();
WRITE_ONCE(filled_random_ptr_key, true);
}
static int __init vsprintf_init_hashval(void)
{
fill_ptr_key_workfn(NULL);
return 0;
}
subsys_initcall(vsprintf_init_hashval)
/* 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_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() ||
!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);
}
if (!READ_ONCE(filled_random_ptr_key))
return -EBUSY;
/* Pairs with smp_wmb() after writing ptr_key. */
smp_rmb();
#ifdef CONFIG_64BIT
hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key);