The following commit has been merged into the sched/rt branch of tip:
Commit-ID: 0e1d5731d3c1e2214249ef36dcd13ad51ad304cf
Gitweb: https://git.kernel.org/tip/0e1d5731d3c1e2214249ef36dcd13ad51ad304cf
Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
AuthorDate: Tue, 20 Aug 2024 08:35:30 +02:06
Committer: Petr Mladek <pmladek@xxxxxxxx>
CommitterDate: Wed, 21 Aug 2024 14:56:22 +02:00
printk: Check printk_deferred_enter()/_exit() usage
Add validation that printk_deferred_enter()/_exit() are called in
non-migration contexts.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: John Ogness <john.ogness@xxxxxxxxxxxxx>
Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>
Link: https://lore.kernel.org/r/20240820063001.36405-5-john.ogness@xxxxxxxxxxxxx
Signed-off-by: Petr Mladek <pmladek@xxxxxxxx>
---
include/linux/printk.h | 9 +++++----
kernel/printk/internal.h | 3 +++
kernel/printk/printk_safe.c | 12 ++++++++++++
3 files changed, 20 insertions(+), 4 deletions(-)
diff --git a/include/linux/printk.h b/include/linux/printk.h
index b937cef..eee8e97 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -161,15 +161,16 @@ int _printk(const char *fmt, ...);
*/
__printf(1, 2) __cold int _printk_deferred(const char *fmt, ...);
-extern void __printk_safe_enter(void);
-extern void __printk_safe_exit(void);
+extern void __printk_deferred_enter(void);
+extern void __printk_deferred_exit(void);
+
/*
* The printk_deferred_enter/exit macros are available only as a hack for
* some code paths that need to defer all printk console printing. Interrupts
* must be disabled for the deferred duration.
*/
-#define printk_deferred_enter __printk_safe_enter
-#define printk_deferred_exit __printk_safe_exit
+#define printk_deferred_enter() __printk_deferred_enter()
+#define printk_deferred_exit() __printk_deferred_exit()
/*
* Please don't use printk_ratelimit(), because it shares ratelimiting state
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index 398ecb4..dc8bc08 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -53,6 +53,9 @@ int vprintk_store(int facility, int level,
__printf(1, 0) int vprintk_default(const char *fmt, va_list args);
__printf(1, 0) int vprintk_deferred(const char *fmt, va_list args);
+void __printk_safe_enter(void);
+void __printk_safe_exit(void);
+
bool printk_percpu_data_ready(void);
#define printk_safe_enter_irqsave(flags) \
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
index 6d10927..4421cca 100644
--- a/kernel/printk/printk_safe.c
+++ b/kernel/printk/printk_safe.c
@@ -26,6 +26,18 @@ void __printk_safe_exit(void)
this_cpu_dec(printk_context);
}
+void __printk_deferred_enter(void)
+{
+ cant_migrate();
+ __printk_safe_enter();
+}
+
+void __printk_deferred_exit(void)
+{
+ cant_migrate();
+ __printk_safe_exit();
+}
+
asmlinkage int vprintk(const char *fmt, va_list args)
{
#ifdef CONFIG_KGDB_KDB
|