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>

1 files changed, 7 insertions, 7 deletions

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;