diff options
| -rw-r--r-- | lib/vsprintf.c | 26 |
1 files changed, 15 insertions, 11 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 30c0cb8cc9bc..23920c5ff728 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -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(¬_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(¬_filled_random_ptr_key)) { spec.field_width = default_width; /* string length must be less than default_width */ return string(buf, end, "(ptrval)", spec); |