treewide: Remove uninitialized_var() usage

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>

10 files changed, 24 insertions, 24 deletions

diff --git a/kernel/async.c b/kernel/async.c
index 4f9c1d614016..33258e6e20f8 100644
--- a/kernel/async.c
+++ b/kernel/async.c
@@ -111,7 +111,7 @@ static void async_run_entry_fn(struct work_struct *work)
 	struct async_entry *entry =
 		container_of(work, struct async_entry, work);
 	unsigned long flags;
-	ktime_t uninitialized_var(calltime), delta, rettime;
+	ktime_t calltime, delta, rettime;
 
 	/* 1) run (and print duration) */
 	if (initcall_debug && system_state < SYSTEM_RUNNING) {
@@ -287,7 +287,7 @@ EXPORT_SYMBOL_GPL(async_synchronize_full_domain);
  */
 void async_synchronize_cookie_domain(async_cookie_t cookie, struct async_domain *domain)
 {
-	ktime_t uninitialized_var(starttime), delta, endtime;
+	ktime_t starttime, delta, endtime;
 
 	if (initcall_debug && system_state < SYSTEM_RUNNING) {
 		pr_debug("async_waiting @ %i\n", task_pid_nr(current));
diff --git a/kernel/audit.c b/kernel/audit.c
index 8c201f414226..ec38479f9228 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1800,7 +1800,7 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 {
 	struct audit_buffer *ab;
 	struct timespec64 t;
-	unsigned int uninitialized_var(serial);
+	unsigned int serial;
 
 	if (audit_initialized != AUDIT_INITIALIZED)
 		return NULL;
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 683a799618ad..9d847ab851db 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -591,7 +591,7 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
 	int this_cpu, old_cpu;
 	char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
 	char *moreprompt = "more> ";
-	unsigned long uninitialized_var(flags);
+	unsigned long flags;
 
 	/* Serialize kdb_printf if multiple cpus try to write at once.
 	 * But if any cpu goes recursive in kdb, just print the output,
diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index 36c962a86bf2..d628ab09d97b 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -882,7 +882,7 @@ static int device_dma_allocations(struct device *dev, struct dma_debug_entry **o
 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
 {
 	struct device *dev = data;
-	struct dma_debug_entry *uninitialized_var(entry);
+	struct dma_debug_entry *entry;
 	int count;
 
 	if (dma_debug_disabled())
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 856d98c36f56..851fc5e0e24b 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11483,7 +11483,7 @@ SYSCALL_DEFINE5(perf_event_open,
 	struct perf_event *group_leader = NULL, *output_event = NULL;
 	struct perf_event *event, *sibling;
 	struct perf_event_attr attr;
-	struct perf_event_context *ctx, *uninitialized_var(gctx);
+	struct perf_event_context *ctx, *gctx;
 	struct file *event_file = NULL;
 	struct fd group = {NULL, 0};
 	struct task_struct *task = NULL;
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index bb0862873dba..e84eb52b646b 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -2189,7 +2189,7 @@ static void handle_swbp(struct pt_regs *regs)
 {
 	struct uprobe *uprobe;
 	unsigned long bp_vaddr;
-	int uninitialized_var(is_swbp);
+	int is_swbp;
 
 	bp_vaddr = uprobe_get_swbp_addr(regs);
 	if (bp_vaddr == get_trampoline_vaddr())
diff --git a/kernel/exit.c b/kernel/exit.c
index 727150f28103..7bcd571618dd 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -93,7 +93,7 @@ static void __exit_signal(struct task_struct *tsk)
 	struct signal_struct *sig = tsk->signal;
 	bool group_dead = thread_group_leader(tsk);
 	struct sighand_struct *sighand;
-	struct tty_struct *uninitialized_var(tty);
+	struct tty_struct *tty;
 	u64 utime, stime;
 
 	sighand = rcu_dereference_check(tsk->sighand,
diff --git a/kernel/futex.c b/kernel/futex.c
index e646661f6282..05e88562de68 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1326,7 +1326,7 @@ static int lookup_pi_state(u32 __user *uaddr, u32 uval,
 static int lock_pi_update_atomic(u32 __user *uaddr, u32 uval, u32 newval)
 {
 	int err;
-	u32 uninitialized_var(curval);
+	u32 curval;
 
 	if (unlikely(should_fail_futex(true)))
 		return -EFAULT;
@@ -1496,7 +1496,7 @@ static void mark_wake_futex(struct wake_q_head *wake_q, struct futex_q *q)
  */
 static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_state)
 {
-	u32 uninitialized_var(curval), newval;
+	u32 curval, newval;
 	struct task_struct *new_owner;
 	bool postunlock = false;
 	DEFINE_WAKE_Q(wake_q);
@@ -2370,7 +2370,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
 				struct task_struct *argowner)
 {
 	struct futex_pi_state *pi_state = q->pi_state;
-	u32 uval, uninitialized_var(curval), newval;
+	u32 uval, curval, newval;
 	struct task_struct *oldowner, *newowner;
 	u32 newtid;
 	int ret, err = 0;
@@ -2996,7 +2996,7 @@ uaddr_faulted:
  */
 static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
 {
-	u32 uninitialized_var(curval), uval, vpid = task_pid_vnr(current);
+	u32 curval, uval, vpid = task_pid_vnr(current);
 	union futex_key key = FUTEX_KEY_INIT;
 	struct futex_hash_bucket *hb;
 	struct futex_q *top_waiter;
@@ -3479,7 +3479,7 @@ err_unlock:
 static int handle_futex_death(u32 __user *uaddr, struct task_struct *curr,
 			      bool pi, bool pending_op)
 {
-	u32 uval, uninitialized_var(nval), mval;
+	u32 uval, nval, mval;
 	int err;
 
 	/* Futex address must be 32bit aligned */
@@ -3609,7 +3609,7 @@ static void exit_robust_list(struct task_struct *curr)
 	struct robust_list_head __user *head = curr->robust_list;
 	struct robust_list __user *entry, *next_entry, *pending;
 	unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
-	unsigned int uninitialized_var(next_pi);
+	unsigned int next_pi;
 	unsigned long futex_offset;
 	int rc;
 
@@ -3909,7 +3909,7 @@ static void compat_exit_robust_list(struct task_struct *curr)
 	struct compat_robust_list_head __user *head = curr->compat_robust_list;
 	struct robust_list __user *entry, *next_entry, *pending;
 	unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
-	unsigned int uninitialized_var(next_pi);
+	unsigned int next_pi;
 	compat_uptr_t uentry, next_uentry, upending;
 	compat_long_t futex_offset;
 	int rc;
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 29a8de4c50b9..84ed1d1d5013 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1723,7 +1723,7 @@ static int noop_count(struct lock_list *entry, void *data)
 static unsigned long __lockdep_count_forward_deps(struct lock_list *this)
 {
 	unsigned long  count = 0;
-	struct lock_list *uninitialized_var(target_entry);
+	struct lock_list *target_entry;
 
 	__bfs_forwards(this, (void *)&count, noop_count, &target_entry);
 
@@ -1749,7 +1749,7 @@ unsigned long lockdep_count_forward_deps(struct lock_class *class)
 static unsigned long __lockdep_count_backward_deps(struct lock_list *this)
 {
 	unsigned long  count = 0;
-	struct lock_list *uninitialized_var(target_entry);
+	struct lock_list *target_entry;
 
 	__bfs_backwards(this, (void *)&count, noop_count, &target_entry);
 
@@ -1804,7 +1804,7 @@ check_noncircular(struct held_lock *src, struct held_lock *target,
 		  struct lock_trace **const trace)
 {
 	int ret;
-	struct lock_list *uninitialized_var(target_entry);
+	struct lock_list *target_entry;
 	struct lock_list src_entry = {
 		.class = hlock_class(src),
 		.parent = NULL,
@@ -1842,7 +1842,7 @@ static noinline int
 check_redundant(struct held_lock *src, struct held_lock *target)
 {
 	int ret;
-	struct lock_list *uninitialized_var(target_entry);
+	struct lock_list *target_entry;
 	struct lock_list src_entry = {
 		.class = hlock_class(src),
 		.parent = NULL,
@@ -2244,8 +2244,8 @@ static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
 {
 	unsigned long usage_mask = 0, forward_mask, backward_mask;
 	enum lock_usage_bit forward_bit = 0, backward_bit = 0;
-	struct lock_list *uninitialized_var(target_entry1);
-	struct lock_list *uninitialized_var(target_entry);
+	struct lock_list *target_entry1;
+	struct lock_list *target_entry;
 	struct lock_list this, that;
 	int ret;
 
@@ -3438,7 +3438,7 @@ check_usage_forwards(struct task_struct *curr, struct held_lock *this,
 {
 	int ret;
 	struct lock_list root;
-	struct lock_list *uninitialized_var(target_entry);
+	struct lock_list *target_entry;
 
 	root.parent = NULL;
 	root.class = hlock_class(this);
@@ -3465,7 +3465,7 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this,
 {
 	int ret;
 	struct lock_list root;
-	struct lock_list *uninitialized_var(target_entry);
+	struct lock_list *target_entry;
 
 	root.parent = NULL;
 	root.class = hlock_class(this);
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 00867ff82412..f15471ce969e 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -577,7 +577,7 @@ static void rb_wake_up_waiters(struct irq_work *work)
  */
 int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full)
 {
-	struct ring_buffer_per_cpu *uninitialized_var(cpu_buffer);
+	struct ring_buffer_per_cpu *cpu_buffer;
 	DEFINE_WAIT(wait);
 	struct rb_irq_work *work;
 	int ret = 0;