Hello Byungchul, Sorry, I'll make sure I Cc you next time. Jan Kara's updated patch set
http://marc.info/?l=linux-kernel&m=145787625506342 it's quite close to what you have done in this patch, but Jan's patch also solves a number of more likely to happen cases. have time to take a look? the lock debug patch in your series is different. can we settle down async printk first and then return to it? it's not so simple... On (03/11/16 19:37), Byungchul Park wrote: [..] > int printk_deferred(const char *fmt, ...) > { > va_list args; > int r; > > preempt_disable(); > + > va_start(args, fmt); > - r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args); > + r = vprintk_deferred(fmt, args); > va_end(args); > + printk_pending_output(); > > - __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT); > - irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); > preempt_enable(); > > return r; vprintk_deferred() does vprintk_emit()->{spin_lock()} again? cosole_lock() is moved out of sight, but logbug_lock is still there. wouldn't this (in the worst case) result in endless loop after all? sorry if I'm missing something. -ss
