On Tue, 30 Mar 2010 13:56:34 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > That new BUG_ON() is triggering in Troels's machine when a bluetooth > keyboard is enabled or disabled. See > (https://bugzilla.kernel.org/show_bug.cgi?id=15648. > > I guess the question is: how did a kernel thread get a non-zero > task->rss_stat.count[i]? If that's expected and OK then we will need > to take some kernel-thread-avoidance action there. > It seems my fault that it's not initialized to be 0 at do_fork(), copy_process. About do_exit, do_exit() does this check. So, tsk->mm can be NULL. 949 if (group_dead) { 950 hrtimer_cancel(&tsk->signal->real_timer); 951 exit_itimers(tsk->signal); 952 if (tsk->mm) 953 setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm); 954 } > Could whoever fixes this please also make __sync_task_rss_stat() > static. > Ah, yes. I should do so. > I'll toss this over to Rafael/Maciej for tracking as a post-2.6.33 > regression. > > Thanks. > == task->rss_stat wasn't initialized to 0 at copy_process(). at exit, tsk->mm may be NULL. And __sync_task_rss_stat() should be static. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> --- kernel/exit.c | 3 ++- kernel/fork.c | 3 +++ mm/memory.c | 2 +- 3 files changed, 6 insertions(+), 2 deletions(-) Index: mmotm-2.6.34-Mar24/kernel/exit.c =================================================================== --- mmotm-2.6.34-Mar24.orig/kernel/exit.c +++ mmotm-2.6.34-Mar24/kernel/exit.c @@ -950,7 +950,8 @@ NORET_TYPE void do_exit(long code) acct_update_integrals(tsk); /* sync mm's RSS info before statistics gathering */ - sync_mm_rss(tsk, tsk->mm); + if (tsk->mm) + sync_mm_rss(tsk, tsk->mm); group_dead = atomic_dec_and_test(&tsk->signal->live); if (group_dead) { hrtimer_cancel(&tsk->signal->real_timer); Index: mmotm-2.6.34-Mar24/mm/memory.c =================================================================== --- mmotm-2.6.34-Mar24.orig/mm/memory.c +++ mmotm-2.6.34-Mar24/mm/memory.c @@ -124,7 +124,7 @@ core_initcall(init_zero_pfn); #if defined(SPLIT_RSS_COUNTING) -void __sync_task_rss_stat(struct task_struct *task, struct mm_struct *mm) +static void __sync_task_rss_stat(struct task_struct *task, struct mm_struct *mm) { int i; Index: mmotm-2.6.34-Mar24/kernel/fork.c =================================================================== --- mmotm-2.6.34-Mar24.orig/kernel/fork.c +++ mmotm-2.6.34-Mar24/kernel/fork.c @@ -1060,6 +1060,9 @@ static struct task_struct *copy_process( p->prev_utime = cputime_zero; p->prev_stime = cputime_zero; #endif +#if defined(SPLIT_RSS_COUNTING) + memset(&p->rss_stat, 0, sizeof(p->rss_stat)); +#endif p->default_timer_slack_ns = current->timer_slack_ns; -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
