[merged] panic-add-an-option-to-replay-all-the-printk-message-in-buffer.patch removed from -mm tree

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The patch titled
     Subject: panic: add an option to replay all the printk message in buffer
has been removed from the -mm tree.  Its filename was
     panic-add-an-option-to-replay-all-the-printk-message-in-buffer.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Feng Tang <feng.tang@xxxxxxxxx>
Subject: panic: add an option to replay all the printk message in buffer

Currently on panic, kernel will lower the loglevel and print out pending
printk msg only with console_flush_on_panic().

Add an option for users to configure the "panic_print" to replay all dmesg
in buffer, some of which they may have never seen due to the loglevel
setting, which will help panic debugging.

[feng.tang@xxxxxxxxx: keep the original console_flush_on_panic() inside panic()]
  Link: http://lkml.kernel.org/r/1556199137-14163-1-git-send-email-feng.tang@xxxxxxxxx
[feng.tang@xxxxxxxxx: use logbuf lock to protect the console log index]
  Link: http://lkml.kernel.org/r/1556269868-22654-1-git-send-email-feng.tang@xxxxxxxxx
Link: http://lkml.kernel.org/r/1556095872-36838-1-git-send-email-feng.tang@xxxxxxxxx
Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>
Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>
Cc: Aaro Koskinen <aaro.koskinen@xxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 Documentation/admin-guide/kernel-parameters.txt |    1 +
 arch/powerpc/kernel/traps.c                     |    2 +-
 include/linux/console.h                         |    7 ++++++-
 kernel/panic.c                                  |    6 +++++-
 kernel/printk/printk.c                          |   12 +++++++++++-
 5 files changed, 24 insertions(+), 4 deletions(-)

--- a/arch/powerpc/kernel/traps.c~panic-add-an-option-to-replay-all-the-printk-message-in-buffer
+++ a/arch/powerpc/kernel/traps.c
@@ -179,7 +179,7 @@ extern void panic_flush_kmsg_end(void)
 	kmsg_dump(KMSG_DUMP_PANIC);
 	bust_spinlocks(0);
 	debug_locks_off();
-	console_flush_on_panic();
+	console_flush_on_panic(CONSOLE_FLUSH_PENDING);
 }
 
 static unsigned long oops_begin(struct pt_regs *regs)
--- a/Documentation/admin-guide/kernel-parameters.txt~panic-add-an-option-to-replay-all-the-printk-message-in-buffer
+++ a/Documentation/admin-guide/kernel-parameters.txt
@@ -3212,6 +3212,7 @@
 			bit 2: print timer info
 			bit 3: print locks info if CONFIG_LOCKDEP is on
 			bit 4: print ftrace buffer
+			bit 5: print all printk messages in buffer
 
 	panic_on_warn	panic() instead of WARN().  Useful to cause kdump
 			on a WARN().
--- a/include/linux/console.h~panic-add-an-option-to-replay-all-the-printk-message-in-buffer
+++ a/include/linux/console.h
@@ -166,6 +166,11 @@ struct console {
 extern int console_set_on_cmdline;
 extern struct console *early_console;
 
+enum con_flush_mode {
+	CONSOLE_FLUSH_PENDING,
+	CONSOLE_REPLAY_ALL,
+};
+
 extern int add_preferred_console(char *name, int idx, char *options);
 extern void register_console(struct console *);
 extern int unregister_console(struct console *);
@@ -175,7 +180,7 @@ extern int console_trylock(void);
 extern void console_unlock(void);
 extern void console_conditional_schedule(void);
 extern void console_unblank(void);
-extern void console_flush_on_panic(void);
+extern void console_flush_on_panic(enum con_flush_mode mode);
 extern struct tty_driver *console_device(int *);
 extern void console_stop(struct console *);
 extern void console_start(struct console *);
--- a/kernel/panic.c~panic-add-an-option-to-replay-all-the-printk-message-in-buffer
+++ a/kernel/panic.c
@@ -51,6 +51,7 @@ EXPORT_SYMBOL_GPL(panic_timeout);
 #define PANIC_PRINT_TIMER_INFO		0x00000004
 #define PANIC_PRINT_LOCK_INFO		0x00000008
 #define PANIC_PRINT_FTRACE_INFO		0x00000010
+#define PANIC_PRINT_ALL_PRINTK_MSG	0x00000020
 unsigned long panic_print;
 
 ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
@@ -134,6 +135,9 @@ EXPORT_SYMBOL(nmi_panic);
 
 static void panic_print_sys_info(void)
 {
+	if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG)
+		console_flush_on_panic(CONSOLE_REPLAY_ALL);
+
 	if (panic_print & PANIC_PRINT_TASK_INFO)
 		show_state();
 
@@ -277,7 +281,7 @@ void panic(const char *fmt, ...)
 	 * panic() is not being callled from OOPS.
 	 */
 	debug_locks_off();
-	console_flush_on_panic();
+	console_flush_on_panic(CONSOLE_FLUSH_PENDING);
 
 	panic_print_sys_info();
 
--- a/kernel/printk/printk.c~panic-add-an-option-to-replay-all-the-printk-message-in-buffer
+++ a/kernel/printk/printk.c
@@ -2535,10 +2535,11 @@ void console_unblank(void)
 
 /**
  * console_flush_on_panic - flush console content on panic
+ * @mode: flush all messages in buffer or just the pending ones
  *
  * Immediately output all pending messages no matter what.
  */
-void console_flush_on_panic(void)
+void console_flush_on_panic(enum con_flush_mode mode)
 {
 	/*
 	 * If someone else is holding the console lock, trylock will fail
@@ -2549,6 +2550,15 @@ void console_flush_on_panic(void)
 	 */
 	console_trylock();
 	console_may_schedule = 0;
+
+	if (mode == CONSOLE_REPLAY_ALL) {
+		unsigned long flags;
+
+		logbuf_lock_irqsave(flags);
+		console_seq = log_first_seq;
+		console_idx = log_first_idx;
+		logbuf_unlock_irqrestore(flags);
+	}
 	console_unlock();
 }
 
_

Patches currently in -mm which might be from feng.tang@xxxxxxxxx are





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