I have checked by setting conditional breakpoints that task->mm is always NULL in those locations. I have also found that task remains NULL many times, but surprisingly the trace_mark() successfully puts the task->pid in the trace file. I am confused as to what is happening ... > On Mon, May 11, 2009 at 8:16 PM, Mulyadi Santosa > <mulyadi.santosa@xxxxxxxxx> wrote: >> Always? hmm strange. sure you did the deferencing to task_struct correctly? look at the following parts of the diff: --------------------------------- diff --git a/kernel/sched.c b/kernel/sched.c index ad1962d..00731d4 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2283,8 +2283,8 @@ out_activate: out_running: trace_mark(kernel_sched_wakeup, - "pid %d state %ld ## rq %p task %p rq->curr %p", - p->pid, p->state, rq, p, rq->curr); + "pid %d state %ld ## rq %p task %p rq->curr %p rq_load %lu page_flt_rate %llu", + p->pid, p->state, rq, p, rq->curr, rq->load.weight, p->mm->page_flt_rate); check_preempt_curr(rq, p); p->state = TASK_RUNNING; @@ -2418,8 +2418,8 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) inc_nr_running(rq); } trace_mark(kernel_sched_wakeup_new, - "pid %d state %ld ## rq %p task %p rq->curr %p", - p->pid, p->state, rq, p, rq->curr); + "pid %d state %ld ## rq %p task %p rq->curr %p rq_load %lu page_flt_rate %llu", + p->pid, p->state, rq, p, rq->curr, rq->load.weight, p->mm->page_flt_rate); check_preempt_curr(rq, p); #ifdef CONFIG_SMP if (p->sched_class->task_wake_up) @@ -2594,9 +2594,9 @@ context_switch(struct rq *rq, struct task_struct *prev, prepare_task_switch(rq, prev, next); trace_mark(kernel_sched_schedule, "prev_pid %d next_pid %d prev_state %ld " - "## rq %p prev %p next %p", + "## rq %p prev %p next %p rq_load %lu page_flt_rate %llu", prev->pid, next->pid, prev->state, - rq, prev, next); + rq, prev, next, rq->load.weight, next->mm->page_flt_rate); mm = next->mm; oldmm = prev->active_mm; /* --------------------------------- -- Regards, Sukanto Ghosh -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ