On Tue, Jul 21, 2015 at 03:32:50PM +0800, Pan Xinhui wrote:
> yes, we may access an freed memory at that time. Because entry is
> stored in rb-tree. Need lock when we access it.
Ah, we touch entry, right.
> > improve the comments over memtype_lock to explain what exactly it protects.
> >
> lock is needed when we access the data stored in rb-tree. :)
I didn't ask you what it protects - I can do my own grepping and read
pat_rbtree.c just fine - I asked you to update the comment.
> I find another bug, although it's very hard to hit.
> just in reserve_memtype()
> ----------------------------------
> err = rbt_memtype_check_insert(new, new_type);
> if (err) {
> printk(KERN_INFO "reserve_memtype failed [mem
> %#010Lx-%#010Lx], track %s, req %s\n",
> start, end - 1,
> cattr_name(new->type), cattr_name(req_type));
> kfree(new);
> spin_unlock(&memtype_lock);
>
> return err;
> }
>
> spin_unlock(&memtype_lock); //this unlock may cause problems because
> the next dprintk access *new*
Yes.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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