Messages in this thread | | | Subject | Re: kmemleak not tainted | From | Catalin Marinas <> | Date | Tue, 07 Jul 2009 13:47:39 +0100 |
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On Tue, 2009-07-07 at 14:51 +0300, Sergey Senozhatsky wrote: > kernel: [ 1917.133154] INFO: RCU detected CPU 0 stall (t=485140/3000 jiffies)
That's the relevant message. With CONFIG_RCU_CPU_STALL_DETECTOR you may get these messages.
> static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias) > { > unsigned long flags; > struct kmemleak_object *object = NULL; > > rcu_read_lock(); > read_lock_irqsave(&kmemleak_lock, flags); > if (ptr >= min_addr && ptr < max_addr) > object = lookup_object(ptr, alias); > >> read_unlock_irqrestore(&kmemleak_lock, flags); > > /* check whether the object is still available */ > if (object && !get_object(object)) > object = NULL; > rcu_read_unlock(); > > return object; > }
It just happened here because that's where the interrupts were enabled and the timer routine invoked. The rcu-locked region above should be pretty short (just a tree look-up).
What I think happens is that the kmemleak thread runs for several seconds for scanning the memory and there may not be any context switches. I have a patch to add more cond_resched() calls throughout the kmemleak_scan() function which I hope will get merged. I don't get any of these messages with CONFIG_PREEMPT enabled.
-- Catalin
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