diff options
Diffstat (limited to 'kernel/rcu/tree_stall.h')
| -rw-r--r-- | kernel/rcu/tree_stall.h | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 29cf096b5d20..353da30bd558 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -482,6 +482,36 @@ static void rcu_check_gp_kthread_starvation(void) } } +/* Complain about missing wakeups from expired fqs wait timer */ +static void rcu_check_gp_kthread_expired_fqs_timer(void) +{ + struct task_struct *gpk = rcu_state.gp_kthread; + short gp_state; + unsigned long jiffies_fqs; + int cpu; + + /* + * Order reads of .gp_state and .jiffies_force_qs. + * Matching smp_wmb() is present in rcu_gp_fqs_loop(). + */ + gp_state = smp_load_acquire(&rcu_state.gp_state); + jiffies_fqs = READ_ONCE(rcu_state.jiffies_force_qs); + + if (gp_state == RCU_GP_WAIT_FQS && + time_after(jiffies, jiffies_fqs + RCU_STALL_MIGHT_MIN) && + gpk && !READ_ONCE(gpk->on_rq)) { + cpu = task_cpu(gpk); + pr_err("%s kthread timer wakeup didn't happen for %ld jiffies! g%ld f%#x %s(%d) ->state=%#lx\n", + rcu_state.name, (jiffies - jiffies_fqs), + (long)rcu_seq_current(&rcu_state.gp_seq), + data_race(rcu_state.gp_flags), + gp_state_getname(RCU_GP_WAIT_FQS), RCU_GP_WAIT_FQS, + gpk->state); + pr_err("\tPossible timer handling issue on cpu=%d timer-softirq=%u\n", + cpu, kstat_softirqs_cpu(TIMER_SOFTIRQ, cpu)); + } +} + static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps) { int cpu; @@ -543,6 +573,7 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps) WRITE_ONCE(rcu_state.jiffies_stall, jiffies + 3 * rcu_jiffies_till_stall_check() + 3); + rcu_check_gp_kthread_expired_fqs_timer(); rcu_check_gp_kthread_starvation(); panic_on_rcu_stall(); @@ -578,6 +609,7 @@ static void print_cpu_stall(unsigned long gps) jiffies - gps, (long)rcu_seq_current(&rcu_state.gp_seq), totqlen); + rcu_check_gp_kthread_expired_fqs_timer(); rcu_check_gp_kthread_starvation(); rcu_dump_cpu_stacks(); |