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-rw-r--r--kernel/printk/Makefile1
-rw-r--r--kernel/printk/internal.h14
-rw-r--r--kernel/printk/printk.c23
-rw-r--r--kernel/printk/printk_safe.c14
4 files changed, 25 insertions, 27 deletions
diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile
index 4a2ffc39eb95..4d052fc6bcde 100644
--- a/kernel/printk/Makefile
+++ b/kernel/printk/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
obj-y = printk.o
obj-$(CONFIG_PRINTK) += printk_safe.o
obj-$(CONFIG_A11Y_BRAILLE_CONSOLE) += braille.o
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index 0f1898820cba..c8e6ab689d42 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -1,18 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* internal.h - printk internal definitions
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/percpu.h>
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 02ca827b8fac..1888f6a3b694 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/printk.c
*
@@ -86,6 +87,12 @@ static DEFINE_SEMAPHORE(console_sem);
struct console *console_drivers;
EXPORT_SYMBOL_GPL(console_drivers);
+/*
+ * System may need to suppress printk message under certain
+ * circumstances, like after kernel panic happens.
+ */
+int __read_mostly suppress_printk;
+
#ifdef CONFIG_LOCKDEP
static struct lockdep_map console_lock_dep_map = {
.name = "console_lock"
@@ -1943,6 +1950,10 @@ asmlinkage int vprintk_emit(int facility, int level,
unsigned long flags;
u64 curr_log_seq;
+ /* Suppress unimportant messages after panic happens */
+ if (unlikely(suppress_printk))
+ return 0;
+
if (level == LOGLEVEL_SCHED) {
level = LOGLEVEL_DEFAULT;
in_sched = true;
@@ -2525,10 +2536,11 @@ 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
@@ -2539,6 +2551,15 @@ 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();
}
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
index 0913b4d385de..b4045e782743 100644
--- a/kernel/printk/printk_safe.c
+++ b/kernel/printk/printk_safe.c
@@ -1,18 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* printk_safe.c - Safe printk for printk-deadlock-prone contexts
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/preempt.h>