diff --git a/MAINTAINERS b/MAINTAINERS
index d7798fdde245..b2eaee98852f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22436,6 +22436,7 @@ M:	Petr Mladek <pmladek@suse.com>
 M:	John Ogness <john.ogness@linutronix.de>
 R:	Steven Rostedt <rostedt@goodmis.org>
 R:	Sergey Senozhatsky <senozhatsky@chromium.org>
+L:	printk@lists.linux.dev
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux.git
 F:	Documentation/core-api/printk-basics.rst
@@ -22444,6 +22445,7 @@ F:	kernel/printk/
 
 PRINTK INDEXING
 R:	Chris Down <chris@chrisdown.name>
+L:	printk@lists.linux.dev
 S:	Maintained
 F:	Documentation/core-api/printk-index.rst
 F:	kernel/printk/index.c
@@ -30062,6 +30064,7 @@ M:	Steven Rostedt <rostedt@goodmis.org>
 R:	Andy Shevchenko <andriy.shevchenko@linux.intel.com>
 R:	Rasmus Villemoes <linux@rasmusvillemoes.dk>
 R:	Sergey Senozhatsky <senozhatsky@chromium.org>
+L:	printk@lists.linux.dev
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux.git
 F:	Documentation/core-api/printk-formats.rst
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 9a205f94bfac..5dbcf8a9909b 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -3792,6 +3792,13 @@ static struct syscore printk_syscore = {
  * If appropriate, start nbcon kthreads and set @printk_kthreads_running.
  * If any kthreads fail to start, those consoles are unregistered.
  *
+ * Called after consoles are registered or unregistered.
+ *
+ * This MUST NOT be called within an hlist_for_each_entry_safe(console_list)
+ * loop because it can unregister multiple consoles if any kthreads fail to
+ * start. That would lead to use-after-free scenarios within the
+ * hlist_for_each_entry_safe(console_list) loop of the caller.
+ *
  * Must be called under console_list_lock().
  */
 static void printk_kthreads_check_locked(void)
@@ -4230,7 +4237,20 @@ void register_console(struct console *newcon)
 }
 EXPORT_SYMBOL(register_console);
 
-/* Must be called under console_list_lock(). */
+/*
+ * Unregister the specified console.
+ *
+ * This can be called safely from within an
+ * hlist_for_each_entry_safe(console_list) loop because it unregisters
+ * _only_ the specified console.
+ *
+ * Afterwards the caller should call printk_kthreads_check_locked() since
+ * unregistering a console may require printer threads to start/stop. Note
+ * that printk_kthreads_check_locked() cannot be called safely from within
+ * an hlist_for_each_entry_safe(console_list) loop.
+ *
+ * Must be called under console_list_lock().
+ */
 static int unregister_console_locked(struct console *console)
 {
 	bool use_device_lock = (console->flags & CON_NBCON) && console->write_atomic;
@@ -4322,9 +4342,6 @@ static int unregister_console_locked(struct console *console)
 	if (console->exit)
 		res = console->exit(console);
 
-	/* Changed console list, may require printer threads to start/stop. */
-	printk_kthreads_check_locked();
-
 	return res;
 }
 
@@ -4333,7 +4350,12 @@ int unregister_console(struct console *console)
 	int res;
 
 	console_list_lock();
+
 	res = unregister_console_locked(console);
+
+	/* Changed console list, may require printer threads to start/stop. */
+	printk_kthreads_check_locked();
+
 	console_list_unlock();
 	return res;
 }
@@ -4472,6 +4494,10 @@ static int __init printk_late_init(void)
 
 		unregister_console_locked(con);
 	}
+
+	/* Changed console list, may require printer threads to start/stop. */
+	printk_kthreads_check_locked();
+
 	console_list_unlock();
 
 	ret = cpuhp_setup_state_nocalls(CPUHP_PRINTK_DEAD, "printk:dead", NULL,
diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c
index d38e7c2f6887..46a79ec0940a 100644
--- a/kernel/printk/printk_ringbuffer.c
+++ b/kernel/printk/printk_ringbuffer.c
@@ -1237,11 +1237,9 @@ static unsigned int space_used(struct prb_data_ring *data_ring,
 	if (BLK_DATALESS(blk_lpos))
 		return 0;
 
-	if (!is_blk_wrapped(data_ring, blk_lpos->begin, blk_lpos->next)) {
-		/* Data block does not wrap. */
-		return (DATA_INDEX(data_ring, blk_lpos->next) -
-			DATA_INDEX(data_ring, blk_lpos->begin));
-	}
+	/* Data block does not wrap. */
+	if (!is_blk_wrapped(data_ring, blk_lpos->begin, blk_lpos->next))
+		return blk_lpos->next - blk_lpos->begin;
 
 	/*
 	 * For wrapping data blocks, the trailing (wasted) space is