Re: [PATCH] drm/ttm: fix error handling in ttm_bo_handle_move_mem()

[Dan Carpenter <dan.carpenter@oracle.com>]

On Wed, Jun 16, 2021 at 10:47:14AM +0200, Christian König wrote:
> 
> 
> Am 16.06.21 um 10:37 schrieb Dan Carpenter:
> > On Wed, Jun 16, 2021 at 08:46:33AM +0200, Christian König wrote:
> > > Sending the first message didn't worked, so let's try again.
> > > 
> > > Am 16.06.21 um 08:30 schrieb Dan Carpenter:
> > > > There are three bugs here:
> > > > 1) We need to call unpopulate() if ttm_tt_populate() succeeds.
> > > > 2) The "new_man = ttm_manager_type(bdev, bo->mem.mem_type);" assignment
> > > >      was wrong and it was really assigning "new_mem = old_mem;".  There
> > > >      is no need for this assignment anyway as we already have the value
> > > >      for "new_mem".
> > > > 3) The (!new_man->use_tt) condition is reversed.
> > > > 
> > > > Fixes: ba4e7d973dd0 ("drm: Add the TTM GPU memory manager subsystem.")
> > > > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > > > ---
> > > > This is from reading the code and I can't swear that I have understood
> > > > it correctly.  My nouveau driver is currently unusable and this patch
> > > > has not helped.  But hopefully if I fix enough bugs eventually it will
> > > > start to work.
> > > Well NAK, the code previously looked quite well and you are breaking it now.
> > > 
> > > What's the problem with nouveau?
> > > 
> > The new Firefox seems to excersize nouveau more than the old one so
> > when I start 10 firefox windows it just hangs the graphics.
> > 
> > I've added debug code and it seems like the problem is that
> > nv50_mem_new() is failing.
> 
> Sounds like it is running out of memory to me.
> 
> Do you have a dmesg?
> 

At first there was a very straight forward use after free bug which I
fixed.
https://lore.kernel.org/nouveau/YMinJwpIei9n1Pn1@mwanda/T/#u

But now the use after free is gone the only thing in dmesg is:
"[TTM] Buffer eviction failed".  And I have some firmware missing.

[  205.489763] rfkill: input handler disabled
[  205.678292] nouveau 0000:01:00.0: Direct firmware load for nouveau/nva8_fuc084 failed with error -2
[  205.678300] nouveau 0000:01:00.0: Direct firmware load for nouveau/nva8_fuc084d failed with error -2
[  205.678302] nouveau 0000:01:00.0: msvld: unable to load firmware data
[  205.678304] nouveau 0000:01:00.0: msvld: init failed, -19
[  296.150632] [TTM] Buffer eviction failed
[  417.084265] [TTM] Buffer eviction failed
[  447.295961] [TTM] Buffer eviction failed
[  510.800231] [TTM] Buffer eviction failed
[  556.101384] [TTM] Buffer eviction failed
[  616.495790] [TTM] Buffer eviction failed
[  692.014007] [TTM] Buffer eviction failed

The eviction failed message only shows up a minute after the hang so it
seems more like a symptom than a root cause.

regards,
dan carpenter