On Mon, Oct 16, 2006 at 11:15:11AM -0700, Andrew Morton wrote:
> On Mon, 16 Oct 2006 01:54:39 -0700
> Ravikiran G Thirumalai <[email protected]> wrote:
>
> The problem is obvious: we have some data (the array caches) and we have a
> data structure which is used to look up that data (cpu_online_map). But
> we're releasing the lock while these two things are in an inconsistent
> state.
>
> So you could have fixed this by taking cache_chain_mutex in CPU_UP_PREPARE
> and releasing it in CPU_ONLINE and CPU_UP_CANCELED.
Hmm, yes. I suppose so. Maybe we can do away with other uses of
lock_cpu_hotplug() in slab.c as well then! Will give it a shot. Slab
locking might look uglier than what it already is though no?
>
> > list_for_each_entry(cachep, &cache_chain, next) {
> > @@ -4087,6 +4088,7 @@ ssize_t slabinfo_write(struct file *file
> > }
> > }
> > mutex_unlock(&cache_chain_mutex);
> > + unlock_cpu_hotplug();
> > if (res >= 0)
> > res = count;
> > return res;
>
> Given that this lock_cpu_hotplug() happens at a high level I guess it'll
> avoid the usual lock_cpu_hotplug() horrors and we can live with it. I
> assume lockdep was enabled when you were testing this?
Not when I tested it. I just retested with lockdep on and things seemed
fine on a SMP.
Thanks,
Kiran
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
