diff options
Diffstat (limited to 'kernel/printk')
| -rw-r--r-- | kernel/printk/printk.c | 9 | ||||
| -rw-r--r-- | kernel/printk/printk_safe.c | 16 |
2 files changed, 20 insertions, 5 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index f96b22db5fe7..31b5e7919d62 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2092,8 +2092,15 @@ static int __init console_setup(char *str) char *s, *options, *brl_options = NULL; int idx; - if (str[0] == 0) + /* + * console="" or console=null have been suggested as a way to + * disable console output. Use ttynull that has been created + * for exacly this purpose. + */ + if (str[0] == 0 || strcmp(str, "null") == 0) { + __add_preferred_console("ttynull", 0, NULL, NULL); return 1; + } if (_braille_console_setup(&str, &brl_options)) return 1; diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c index 64f8046586b6..477f19e645d1 100644 --- a/kernel/printk/printk_safe.c +++ b/kernel/printk/printk_safe.c @@ -56,6 +56,8 @@ struct printk_safe_seq_buf { static DEFINE_PER_CPU(struct printk_safe_seq_buf, safe_print_seq); static DEFINE_PER_CPU(int, printk_context); +static DEFINE_RAW_SPINLOCK(safe_read_lock); + #ifdef CONFIG_PRINTK_NMI static DEFINE_PER_CPU(struct printk_safe_seq_buf, nmi_print_seq); #endif @@ -194,8 +196,6 @@ static void report_message_lost(struct printk_safe_seq_buf *s) */ static void __printk_safe_flush(struct irq_work *work) { - static raw_spinlock_t read_lock = - __RAW_SPIN_LOCK_INITIALIZER(read_lock); struct printk_safe_seq_buf *s = container_of(work, struct printk_safe_seq_buf, work); unsigned long flags; @@ -209,7 +209,7 @@ static void __printk_safe_flush(struct irq_work *work) * different CPUs. This is especially important when printing * a backtrace. */ - raw_spin_lock_irqsave(&read_lock, flags); + raw_spin_lock_irqsave(&safe_read_lock, flags); i = 0; more: @@ -246,7 +246,7 @@ more: out: report_message_lost(s); - raw_spin_unlock_irqrestore(&read_lock, flags); + raw_spin_unlock_irqrestore(&safe_read_lock, flags); } /** @@ -292,6 +292,14 @@ void printk_safe_flush_on_panic(void) raw_spin_lock_init(&logbuf_lock); } + if (raw_spin_is_locked(&safe_read_lock)) { + if (num_online_cpus() > 1) + return; + + debug_locks_off(); + raw_spin_lock_init(&safe_read_lock); + } + printk_safe_flush(); } |