Merge branch 'for-4.13' into for-linus

This commit is contained in:
Petr Mladek 2017-07-03 15:33:39 +02:00
commit a5707eef79
4 changed files with 51 additions and 15 deletions

View File

@ -18,12 +18,14 @@
#ifdef CONFIG_PRINTK
#define PRINTK_SAFE_CONTEXT_MASK 0x7fffffff
#define PRINTK_NMI_CONTEXT_MASK 0x80000000
#define PRINTK_SAFE_CONTEXT_MASK 0x3fffffff
#define PRINTK_NMI_DEFERRED_CONTEXT_MASK 0x40000000
#define PRINTK_NMI_CONTEXT_MASK 0x80000000
extern raw_spinlock_t logbuf_lock;
__printf(1, 0) int vprintk_default(const char *fmt, va_list args);
__printf(1, 0) int vprintk_deferred(const char *fmt, va_list args);
__printf(1, 0) int vprintk_func(const char *fmt, va_list args);
void __printk_safe_enter(void);
void __printk_safe_exit(void);

View File

@ -2720,20 +2720,29 @@ void wake_up_klogd(void)
preempt_enable();
}
int vprintk_deferred(const char *fmt, va_list args)
{
int r;
r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args);
preempt_disable();
__this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
preempt_enable();
return r;
}
int printk_deferred(const char *fmt, ...)
{
va_list args;
int r;
preempt_disable();
va_start(args, fmt);
r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args);
r = vprintk_deferred(fmt, args);
va_end(args);
__this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
preempt_enable();
return r;
}

View File

@ -80,8 +80,8 @@ static void queue_flush_work(struct printk_safe_seq_buf *s)
* happen, printk_safe_log_store() will notice the buffer->len mismatch
* and repeat the write.
*/
static int printk_safe_log_store(struct printk_safe_seq_buf *s,
const char *fmt, va_list args)
static __printf(2, 0) int printk_safe_log_store(struct printk_safe_seq_buf *s,
const char *fmt, va_list args)
{
int add;
size_t len;
@ -299,7 +299,7 @@ void printk_safe_flush_on_panic(void)
* one writer running. But the buffer might get flushed from another
* CPU, so we need to be careful.
*/
static int vprintk_nmi(const char *fmt, va_list args)
static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args)
{
struct printk_safe_seq_buf *s = this_cpu_ptr(&nmi_print_seq);
@ -308,17 +308,29 @@ static int vprintk_nmi(const char *fmt, va_list args)
void printk_nmi_enter(void)
{
this_cpu_or(printk_context, PRINTK_NMI_CONTEXT_MASK);
/*
* The size of the extra per-CPU buffer is limited. Use it only when
* the main one is locked. If this CPU is not in the safe context,
* the lock must be taken on another CPU and we could wait for it.
*/
if ((this_cpu_read(printk_context) & PRINTK_SAFE_CONTEXT_MASK) &&
raw_spin_is_locked(&logbuf_lock)) {
this_cpu_or(printk_context, PRINTK_NMI_CONTEXT_MASK);
} else {
this_cpu_or(printk_context, PRINTK_NMI_DEFERRED_CONTEXT_MASK);
}
}
void printk_nmi_exit(void)
{
this_cpu_and(printk_context, ~PRINTK_NMI_CONTEXT_MASK);
this_cpu_and(printk_context,
~(PRINTK_NMI_CONTEXT_MASK |
PRINTK_NMI_DEFERRED_CONTEXT_MASK));
}
#else
static int vprintk_nmi(const char *fmt, va_list args)
static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args)
{
return 0;
}
@ -330,7 +342,7 @@ static int vprintk_nmi(const char *fmt, va_list args)
* into itself. It uses a per-CPU buffer to store the message, just like
* NMI.
*/
static int vprintk_safe(const char *fmt, va_list args)
static __printf(1, 0) int vprintk_safe(const char *fmt, va_list args)
{
struct printk_safe_seq_buf *s = this_cpu_ptr(&safe_print_seq);
@ -351,12 +363,22 @@ void __printk_safe_exit(void)
__printf(1, 0) int vprintk_func(const char *fmt, va_list args)
{
/* Use extra buffer in NMI when logbuf_lock is taken or in safe mode. */
if (this_cpu_read(printk_context) & PRINTK_NMI_CONTEXT_MASK)
return vprintk_nmi(fmt, args);
/* Use extra buffer to prevent a recursion deadlock in safe mode. */
if (this_cpu_read(printk_context) & PRINTK_SAFE_CONTEXT_MASK)
return vprintk_safe(fmt, args);
/*
* Use the main logbuf when logbuf_lock is available in NMI.
* But avoid calling console drivers that might have their own locks.
*/
if (this_cpu_read(printk_context) & PRINTK_NMI_DEFERRED_CONTEXT_MASK)
return vprintk_deferred(fmt, args);
/* No obstacles. */
return vprintk_default(fmt, args);
}

View File

@ -86,9 +86,11 @@ void nmi_trigger_cpumask_backtrace(const cpumask_t *mask,
bool nmi_cpu_backtrace(struct pt_regs *regs)
{
static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
int cpu = smp_processor_id();
if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
arch_spin_lock(&lock);
if (regs && cpu_in_idle(instruction_pointer(regs))) {
pr_warn("NMI backtrace for cpu %d skipped: idling at pc %#lx\n",
cpu, instruction_pointer(regs));
@ -99,6 +101,7 @@ bool nmi_cpu_backtrace(struct pt_regs *regs)
else
dump_stack();
}
arch_spin_unlock(&lock);
cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
return true;
}