Revert "drivers/tty: Explicitly pass current to show_stack"

This reverts commit 9f12cea96f47f98d612a0a0b84f950a0163731bf.

Mark writes:
Unfortunately, this patch will result in erroneous stack traces
on some architectures. Sorry about this; I should have verified
this more thoroughly before sending the series out.

Please drop the patch at your earliest convenience.

Cc: Mark Rutland <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/sysrq.c

···
 
 	spin_lock_irqsave(&show_lock, flags);
 	pr_info("CPU%d:\n", smp_processor_id());
-	show_stack(current, NULL);
+	show_stack(NULL, NULL);
 	spin_unlock_irqrestore(&show_lock, flags);
 }