Merge tag 'printk-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

Pull printk updates from Petr Mladek:

 - Do not try to get the console lock when it is not need or useful in
   panic()

 - Replace the global console_suspended state by a per-console flag

 - Export symbols needed for dumping the raw printk buffer in panic()

 - Fix documentation of printf formats for integer types

 - Moved Sergey Senozhatsky to the reviewer role

 - Misc cleanups

* tag 'printk-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
  printk: export symbols for debug modules
  lib: test_scanf: Add explicit type cast to result initialization in test_number_prefix()
  printk: ringbuffer: Fix truncating buffer size min_t cast
  printk: Rename abandon_console_lock_in_panic() to other_cpu_in_panic()
  printk: Add per-console suspended state
  printk: Consolidate console deferred printing
  printk: Do not take console lock for console_flush_on_panic()
  printk: Keep non-panic-CPUs out of console lock
  printk: Reduce console_unblank() usage in unsafe scenarios
  kdb: Do not assume write() callback available
  docs: printk-formats: Treat char as always unsigned
  docs: printk-formats: Fix hex printing of signed values
  MAINTAINERS: adjust printk/vsprintf entries

Documentation/core-api/printk-formats.rst

@@ -15,9 +15,10 @@ Integer types
 
 	If variable is of Type,		use printk format specifier:
 	------------------------------------------------------------
-		char			%d or %x
+		signed char		%d or %hhx
 		unsigned char		%u or %x
-		short int		%d or %x
+		char			%u or %x
+		short int		%d or %hx
 		unsigned short int	%u or %x
 		int			%d or %x
 		unsigned int		%u or %x
@@ -27,9 +28,9 @@ Integer types
 		unsigned long long	%llu or %llx
 		size_t			%zu or %zx
 		ssize_t			%zd or %zx
-		s8			%d or %x
+		s8			%d or %hhx
 		u8			%u or %x
-		s16			%d or %x
+		s16			%d or %hx
 		u16			%u or %x
 		s32			%d or %x
 		u32			%u or %x

MAINTAINERS

@@ -17176,9 +17176,9 @@ F:	kernel/sched/psi.c
 
 PRINTK
 M:	Petr Mladek <pmladek@suse.com>
-M:	Sergey Senozhatsky <senozhatsky@chromium.org>
 R:	Steven Rostedt <rostedt@goodmis.org>
 R:	John Ogness <john.ogness@linutronix.de>
+R:	Sergey Senozhatsky <senozhatsky@chromium.org>
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux.git
 F:	include/linux/printk.h
@@ -23072,9 +23072,9 @@ F:	drivers/net/vrf.c
 VSPRINTF
 M:	Petr Mladek <pmladek@suse.com>
 M:	Steven Rostedt <rostedt@goodmis.org>
-M:	Sergey Senozhatsky <senozhatsky@chromium.org>
 R:	Andy Shevchenko <andriy.shevchenko@linux.intel.com>
 R:	Rasmus Villemoes <linux@rasmusvillemoes.dk>
+R:	Sergey Senozhatsky <senozhatsky@chromium.org>
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux.git
 F:	Documentation/core-api/printk-formats.rst

include/linux/console.h

@@ -154,6 +154,8 @@ static inline int con_debug_leave(void)
  *			receiving the printk spam for obvious reasons.
  * @CON_EXTENDED:	The console supports the extended output format of
  *			/dev/kmesg which requires a larger output buffer.
+ * @CON_SUSPENDED:	Indicates if a console is suspended. If true, the
+ *			printing callbacks must not be called.
  */
 enum cons_flags {
 	CON_PRINTBUFFER		= BIT(0),
@@ -163,6 +165,7 @@ enum cons_flags {
 	CON_ANYTIME		= BIT(4),
 	CON_BRL			= BIT(5),
 	CON_EXTENDED		= BIT(6),
+	CON_SUSPENDED		= BIT(7),
 };
 
 /**

kernel/debug/kdb/kdb_io.c

@@ -590,6 +590,8 @@ static void kdb_msg_write(const char *msg, int msg_len)
 			continue;
 		if (c == dbg_io_ops->cons)
 			continue;
+		if (!c->write)
+			continue;
 		/*
 		 * Set oops_in_progress to encourage the console drivers to
 		 * disregard their internal spin locks: in the current calling

kernel/printk/internal.h

@@ -103,3 +103,5 @@ struct printk_message {
 	u64			seq;
 	unsigned long		dropped;
 };
+
+bool other_cpu_in_panic(void);

kernel/printk/printk_ringbuffer.c

@@ -1735,7 +1735,7 @@ static bool copy_data(struct prb_data_ring *data_ring,
 	if (!buf || !buf_size)
 		return true;
 
-	data_size = min_t(u16, buf_size, len);
+	data_size = min_t(unsigned int, buf_size, len);
 
 	memcpy(&buf[0], data, data_size); /* LMM(copy_data:A) */
 	return true;

kernel/printk/printk_safe.c

@@ -38,13 +38,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 	 * Use the main logbuf even in NMI. But avoid calling console
 	 * drivers that might have their own locks.
 	 */
-	if (this_cpu_read(printk_context) || in_nmi()) {
-		int len;
-
-		len = vprintk_store(0, LOGLEVEL_DEFAULT, NULL, fmt, args);
-		defer_console_output();
-		return len;
-	}
+	if (this_cpu_read(printk_context) || in_nmi())
+		return vprintk_deferred(fmt, args);
 
 	/* No obstacles. */
 	return vprintk_default(fmt, args);

lib/test_scanf.c

@@ -606,7 +606,7 @@ static void __init numbers_slice(void)
 #define test_number_prefix(T, str, scan_fmt, expect0, expect1, n_args, fn)	\
 do {										\
 	const T expect[2] = { expect0, expect1 };				\
-	T result[2] = {~expect[0], ~expect[1]};					\
+	T result[2] = { (T)~expect[0], (T)~expect[1] };				\
 										\
 	_test(fn, &expect, str, scan_fmt, n_args, &result[0], &result[1]);	\
 } while (0)