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author | Petr Mladek <pmladek@suse.com> | 2022-10-04 15:55:44 +0200 |
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committer | Petr Mladek <pmladek@suse.com> | 2022-10-04 15:55:44 +0200 |
commit | da743a92e5895eb1b225de7d9806274fdbd43061 (patch) | |
tree | fb2808ba7bf7e4f03466ea5787ba89f85063da94 /lib/vsprintf.c | |
parent | dc453dd89daacdc0da6d66234aa27e417df7edcd (diff) | |
parent | 6f0ac3b52a9075b7291a72fb338d08491c1f0a64 (diff) | |
download | linux-da743a92e5895eb1b225de7d9806274fdbd43061.tar.gz linux-da743a92e5895eb1b225de7d9806274fdbd43061.tar.bz2 linux-da743a92e5895eb1b225de7d9806274fdbd43061.zip |
Merge branch 'for-6.1-hash-pointer-init' into for-linus
Diffstat (limited to 'lib/vsprintf.c')
-rw-r--r-- | lib/vsprintf.c | 47 |
1 files changed, 26 insertions, 21 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 07b36d8b29c3..a7407ebe949c 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -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); |