On Wed, 2012-08-29 at 16:50 +0300, Alexey Dobriyan wrote:
> On Wed, Aug 29, 2012 at 7:11 AM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:
> > I'll polish this patch once LKS/LPC is over...
>
> It should oops in the following way (excuse Gmail please):
> PDEO is removed from lists
> ->pde_users is 0
> PDE won't be in purge queue -- no ->release while module is alive
>
> Current code removes PDEO and checks if PDE scheduled for removal atomically.
>
> proc_reg_release remove_proc_entry
>
> de->proc_fops = NULL;
> release = pde_opener_del(inode, file);
> rcu_read_lock();
> synchronize_rcu();
> fops = rcu_dereference(pde->proc_fops);
> if (!fops) {
> rcu_read_unlock();
> ----------------------------------
> /* NOP */
> while
> (atomic_read(&de->pde_users))
> ...
> /* NOP */
>
> pde_openers_purge(de, &purge_queue);
> /* NOP */
> while
> (!list_empty(&purge_queue))
> ...
> rmmod
>
> if (release)
> release(inode, file) /* OOPS */
Fix should be trivial, proper module refcount for example.
As I said, I would do that after LKS/LPC, there is no hurry.
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