Hi Chirag, Please apply this patch to your 26.5-rt9 tree for ppc64, enable CONFIG_PROVE_LOCKING (which enables CONFIG_STACKTRACE) and give it a whirl. If you get an oops, please post the console output. Thanks! -Greg ------------------ sched: add a stacktrace on enqueue_pushable error NOT FOR INCLUSION! This is to help debug an issue discovered by Chirag Jog in the thread http://lkml.org/lkml/2008/9/25/189 Signed-off-by: Gregory Haskins <ghaskins@xxxxxxxxxx> --- include/linux/sched.h | 6 ++++++ kernel/sched_rt.c | 20 +++++++++++++++++++- 2 files changed, 25 insertions(+), 1 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 67da014..53e8a6a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -87,6 +87,7 @@ struct sched_param { #include <linux/task_io_accounting.h> #include <linux/kobject.h> #include <linux/latencytop.h> +#include <linux/stacktrace.h> #include <asm/processor.h> @@ -1170,6 +1171,11 @@ struct task_struct { struct list_head tasks; struct plist_node pushable_tasks; + struct { + unsigned long data[15]; + struct stack_trace trace; + pid_t pid; + } pushable_stack; /* * ptrace_list/ptrace_children forms the list of my children diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 57a0c0d..0e6a88c 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -55,7 +55,25 @@ static void update_rt_migration(struct rq *rq) static void enqueue_pushable_task(struct rq *rq, struct task_struct *p) { - plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks); + if (plist_node_empty(&p->pushable_tasks)) { + struct stack_trace *trace = &p->pushable_stack.trace; + + trace->nr_entries = 0; + trace->max_entries = sizeof(p->pushable_stack.data)/sizeof(p->pushable_stack.data[0]); + trace->entries = &p->pushable_stack.data[0]; + trace->skip = 0; + + save_stack_trace(trace); + + p->pushable_stack.pid = current->pid; + } else { + printk(KERN_CRIT "redundant enqueue by %d detected\n", + p->pushable_stack.pid); + print_stack_trace(&p->pushable_stack.trace, 5); + + BUG_ON(!plist_node_empty(&p->pushable_tasks)); + } + plist_node_init(&p->pushable_tasks, p->prio); plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks); } -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
