[Intel-gfx] [PATCH 1/2] drm/i915/gem: Replace reloc chain with terminator on error unwind

[Chris Wilson]

Quoting Pavel Machek (2020-08-19 20:47:23)
> Hi!
> 
> > > Yep, my machines are low on memory.
> > > 
> > > But ... test did not work that well. I have dead X and blinking
> > > screen. Machine still works reasonably well over ssh, so I guess
> > > that's an improvement.
> > 
> > > [ 7744.718473] BUG: unable to handle page fault for address: f8c00000
> > > [ 7744.718484] #PF: supervisor write access in kernel mode
> > > [ 7744.718487] #PF: error_code(0x0002) - not-present page
> > > [ 7744.718491] *pdpt = 0000000031b0b001 *pde = 0000000000000000 
> > > [ 7744.718500] Oops: 0002 [#1] PREEMPT SMP PTI
> > > [ 7744.718506] CPU: 0 PID: 3004 Comm: Xorg Not tainted 5.9.0-rc1-next-20200819+ #134
> > > [ 7744.718509] Hardware name: LENOVO 17097HU/17097HU, BIOS 7BETD8WW (2.19 ) 03/31/2011
> > > [ 7744.718518] EIP: eb_relocate_vma+0xdbf/0xf20
> > 
> > To save me guessing, paste the above location into
> >       ./scripts/decode_stacktrace.sh ./vmlinux . ./drivers/gpu/drm/i915
> > 
> > The f8c00000 is something running off the end of a kmap, but I didn't
> > spot a path were we would ignore an error and keep on writing.
> > Nevertheless it must exist.
> 
> Like this?
> 
> $ ./scripts/decode_stacktrace.sh ./vmlinux . ./drivers/gpu/drm/i915
> f8c00000
> f8c00000
> eb_relocate_vma+0xdbf/0xf20
> eb_relocate_vma (i915_gem_execbuffer.c:?) 

Ok, that didn't work as well as I'm used to. Thanks,
-Chris