diff options
| -rw-r--r-- | Documentation/sysctl/kernel.txt | 12 | ||||
| -rw-r--r-- | include/linux/kernel.h | 1 | ||||
| -rw-r--r-- | kernel/rcu/tree.c | 12 | ||||
| -rw-r--r-- | kernel/sysctl.c | 11 |
4 files changed, 36 insertions, 0 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index a3683ce2a2f3..33204604de6c 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -58,6 +58,7 @@ show up in /proc/sys/kernel: - panic_on_stackoverflow - panic_on_unrecovered_nmi - panic_on_warn +- panic_on_rcu_stall - perf_cpu_time_max_percent - perf_event_paranoid - perf_event_max_stack @@ -618,6 +619,17 @@ a kernel rebuild when attempting to kdump at the location of a WARN(). ============================================================== +panic_on_rcu_stall: + +When set to 1, calls panic() after RCU stall detection messages. This +is useful to define the root cause of RCU stalls using a vmcore. + +0: do not panic() when RCU stall takes place, default behavior. + +1: panic() after printing RCU stall messages. + +============================================================== + perf_cpu_time_max_percent: Hints to the kernel how much CPU time it should be allowed to diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 94aa10ffe156..c42082112ec8 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -451,6 +451,7 @@ extern int panic_on_oops; extern int panic_on_unrecovered_nmi; extern int panic_on_io_nmi; extern int panic_on_warn; +extern int sysctl_panic_on_rcu_stall; extern int sysctl_panic_on_stackoverflow; extern bool crash_kexec_post_notifiers; diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index c844b6142a86..e5ca15a461b9 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -125,6 +125,8 @@ int rcu_num_lvls __read_mostly = RCU_NUM_LVLS; /* Number of rcu_nodes at specified level. */ static int num_rcu_lvl[] = NUM_RCU_LVL_INIT; int rcu_num_nodes __read_mostly = NUM_RCU_NODES; /* Total # rcu_nodes in use. */ +/* panic() on RCU Stall sysctl. */ +int sysctl_panic_on_rcu_stall __read_mostly; /* * The rcu_scheduler_active variable transitions from zero to one just @@ -1312,6 +1314,12 @@ static void rcu_stall_kick_kthreads(struct rcu_state *rsp) } } +static inline void panic_on_rcu_stall(void) +{ + if (sysctl_panic_on_rcu_stall) + panic("RCU Stall\n"); +} + static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum) { int cpu; @@ -1391,6 +1399,8 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum) rcu_check_gp_kthread_starvation(rsp); + panic_on_rcu_stall(); + force_quiescent_state(rsp); /* Kick them all. */ } @@ -1431,6 +1441,8 @@ static void print_cpu_stall(struct rcu_state *rsp) jiffies + 3 * rcu_jiffies_till_stall_check() + 3); raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + panic_on_rcu_stall(); + /* * Attempt to revive the RCU machinery by forcing a context switch. * diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 87b2fc38398b..35f0dcb1cb4f 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1205,6 +1205,17 @@ static struct ctl_table kern_table[] = { .extra2 = &one, }, #endif +#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU) + { + .procname = "panic_on_rcu_stall", + .data = &sysctl_panic_on_rcu_stall, + .maxlen = sizeof(sysctl_panic_on_rcu_stall), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &one, + }, +#endif { } }; |