diff options
| -rw-r--r-- | kernel/printk/internal.h | 2 | ||||
| -rw-r--r-- | kernel/printk/printk_safe.c | 11 |
2 files changed, 12 insertions, 1 deletions
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h index 44468f3828f3..84706c1c934b 100644 --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -75,6 +75,7 @@ bool printk_percpu_data_ready(void); } while (0) void defer_console_output(void); +bool is_printk_legacy_deferred(void); u16 printk_parse_prefix(const char *text, int *level, enum printk_info_flags *flags); @@ -138,6 +139,7 @@ static inline bool console_is_usable(struct console *con, short flags) #define printk_safe_exit_irqrestore(flags) local_irq_restore(flags) static inline bool printk_percpu_data_ready(void) { return false; } +static inline bool is_printk_legacy_deferred(void) { return false; } static inline u64 nbcon_seq_read(struct console *con) { return 0; } static inline void nbcon_seq_force(struct console *con, u64 seq) { } static inline bool nbcon_alloc(struct console *con) { return false; } diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c index 4421ccac3113..86439fd20aab 100644 --- a/kernel/printk/printk_safe.c +++ b/kernel/printk/printk_safe.c @@ -38,6 +38,15 @@ void __printk_deferred_exit(void) __printk_safe_exit(); } +bool is_printk_legacy_deferred(void) +{ + /* + * The per-CPU variable @printk_context can be read safely in any + * context. CPU migration is always disabled when set. + */ + return (this_cpu_read(printk_context) || in_nmi()); +} + asmlinkage int vprintk(const char *fmt, va_list args) { #ifdef CONFIG_KGDB_KDB @@ -50,7 +59,7 @@ 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()) + if (is_printk_legacy_deferred()) return vprintk_deferred(fmt, args); /* No obstacles. */ |