mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-05 00:20:32 +00:00
printk: robustify printk
Avoid deadlocks against rq->lock and xtime_lock by deferring the klogd wakeup by polling from the timer tick. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
parent
796aadeb1b
commit
b845b517b5
4 changed files with 23 additions and 3 deletions
|
@ -200,6 +200,8 @@ extern struct ratelimit_state printk_ratelimit_state;
|
||||||
extern int printk_ratelimit(void);
|
extern int printk_ratelimit(void);
|
||||||
extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
|
extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
|
||||||
unsigned int interval_msec);
|
unsigned int interval_msec);
|
||||||
|
extern void printk_tick(void);
|
||||||
|
extern int printk_needs_cpu(int);
|
||||||
#else
|
#else
|
||||||
static inline int vprintk(const char *s, va_list args)
|
static inline int vprintk(const char *s, va_list args)
|
||||||
__attribute__ ((format (printf, 1, 0)));
|
__attribute__ ((format (printf, 1, 0)));
|
||||||
|
@ -211,6 +213,8 @@ static inline int printk_ratelimit(void) { return 0; }
|
||||||
static inline bool printk_timed_ratelimit(unsigned long *caller_jiffies, \
|
static inline bool printk_timed_ratelimit(unsigned long *caller_jiffies, \
|
||||||
unsigned int interval_msec) \
|
unsigned int interval_msec) \
|
||||||
{ return false; }
|
{ return false; }
|
||||||
|
static inline void printk_tick(void) { }
|
||||||
|
static inline int printk_needs_cpu(int) { return 0; }
|
||||||
#endif
|
#endif
|
||||||
|
|
||||||
extern void asmlinkage __attribute__((format(printf, 1, 2)))
|
extern void asmlinkage __attribute__((format(printf, 1, 2)))
|
||||||
|
|
|
@ -982,10 +982,25 @@ int is_console_locked(void)
|
||||||
return console_locked;
|
return console_locked;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
static DEFINE_PER_CPU(int, printk_pending);
|
||||||
|
|
||||||
|
void printk_tick(void)
|
||||||
|
{
|
||||||
|
if (__get_cpu_var(printk_pending)) {
|
||||||
|
__get_cpu_var(printk_pending) = 0;
|
||||||
|
wake_up_interruptible(&log_wait);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
int printk_needs_cpu(int cpu)
|
||||||
|
{
|
||||||
|
return per_cpu(printk_pending, cpu);
|
||||||
|
}
|
||||||
|
|
||||||
void wake_up_klogd(void)
|
void wake_up_klogd(void)
|
||||||
{
|
{
|
||||||
if (!oops_in_progress && waitqueue_active(&log_wait))
|
if (waitqueue_active(&log_wait))
|
||||||
wake_up_interruptible(&log_wait);
|
__get_cpu_var(printk_pending) = 1;
|
||||||
}
|
}
|
||||||
|
|
||||||
/**
|
/**
|
||||||
|
|
|
@ -255,7 +255,7 @@ void tick_nohz_stop_sched_tick(int inidle)
|
||||||
next_jiffies = get_next_timer_interrupt(last_jiffies);
|
next_jiffies = get_next_timer_interrupt(last_jiffies);
|
||||||
delta_jiffies = next_jiffies - last_jiffies;
|
delta_jiffies = next_jiffies - last_jiffies;
|
||||||
|
|
||||||
if (rcu_needs_cpu(cpu))
|
if (rcu_needs_cpu(cpu) || printk_needs_cpu(cpu))
|
||||||
delta_jiffies = 1;
|
delta_jiffies = 1;
|
||||||
/*
|
/*
|
||||||
* Do not stop the tick, if we are only one off
|
* Do not stop the tick, if we are only one off
|
||||||
|
|
|
@ -978,6 +978,7 @@ void update_process_times(int user_tick)
|
||||||
run_local_timers();
|
run_local_timers();
|
||||||
if (rcu_pending(cpu))
|
if (rcu_pending(cpu))
|
||||||
rcu_check_callbacks(cpu, user_tick);
|
rcu_check_callbacks(cpu, user_tick);
|
||||||
|
printk_tick();
|
||||||
scheduler_tick();
|
scheduler_tick();
|
||||||
run_posix_cpu_timers(p);
|
run_posix_cpu_timers(p);
|
||||||
}
|
}
|
||||||
|
|
Loading…
Reference in a new issue