treewide: Remove uninitialized_var() usage

commit 3f649ab728cda8038259d8f14492fe400fbab911 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

9 files changed, 17 insertions, 17 deletions

diff --git a/kernel/async.c b/kernel/async.c
index 4bf1b00a28d8..e59bd2240cb8 100644
--- a/kernel/async.c
+++ b/kernel/async.c
@@ -115,7 +115,7 @@ 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) {
@@ -283,7 +283,7 @@ 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 7dc14a4d9e3c..471d3ad910aa 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1796,7 +1796,7 @@ 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/dma/debug.c b/kernel/dma/debug.c
index 7c6cd00d0fca..c345a6e2f7b7 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -963,7 +963,7 @@ 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 2bf4b6b109bf..b9c2f9b2a881 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10575,7 +10575,7 @@ 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 24342bca11f2..72ae05d65066 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1887,7 +1887,7 @@ 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 02360ec3b122..0d1cca15e66f 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -140,7 +140,7 @@ 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 3c67da9b8408..ca2a2a894839 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1398,7 +1398,7 @@ 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;
@@ -1569,7 +1569,7 @@ 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);
@@ -3083,7 +3083,7 @@ 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;
@@ -3558,7 +3558,7 @@ 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 */
@@ -3688,7 +3688,7 @@ 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;
 
@@ -3987,7 +3987,7 @@ 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 4dc79f57af82..46a6d1f7c351 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1246,7 +1246,7 @@ 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);
 
@@ -1274,7 +1274,7 @@ 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);
 
@@ -2662,7 +2662,7 @@ 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 ba8b72f9cdc0..089c0a1c44c0 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -561,7 +561,7 @@ static void rb_wake_up_waiters(struct irq_work *work)
  */
 int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool 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;