Re: [PATCHv4 02/17] zram: do not use per-CPU compression streams

[Sergey Senozhatsky]

On (25/02/09 01:20), Sergey Senozhatsky wrote:
> So I moved lockdep class keys to per-zram device and per-zsmalloc pool
> to separate the lockdep chains.  Looks like that did the trick.
> 
> 
[..]
> 
> [ 1714.900906] [    T172] Chain exists of:
>                             ptlock_ptr(ptdesc)#2 --> zram-entry->lock --> &zstrm->lock
> 
> [ 1714.903183] [    T172]  Possible unsafe locking scenario:
> 
> [ 1714.904463] [    T172]        CPU0                    CPU1
> [ 1714.905380] [    T172]        ----                    ----
> [ 1714.906293] [    T172]   lock(&zstrm->lock);
> [ 1714.907006] [    T172]                                lock(zram-entry->lock);
> [ 1714.908204] [    T172]                                lock(&zstrm->lock);
> [ 1714.909347] [    T172]   lock(ptlock_ptr(ptdesc)#2);
> [ 1714.910179] [    T172]
>                            *** DEADLOCK ***

Actually, let me look at this more.  Maybe I haven't figured it out yet.