Re: Radeon KMS regression still present in 2.6.33-rc6

From: Johannes Hirte
Date: Sat Jan 30 2010 - 14:50:29 EST


Am Samstag 30 Januar 2010 18:43:52 schrieb Linus Torvalds:
> On Sat, 30 Jan 2010, Kevin Winchester wrote:
> > I took a picture of the crash details:
> >
> > http://picasaweb.google.ca/kjwinchester/LinuxKernelPanic#5432580230065271
> > 634
> >
> > In case it helps, here is the gdb listing for the problem address:
> >
> > (gdb) l *(radeon_agp_init+0x1d)
> > 0xffffffff811c1592 is in radeon_agp_init
> > (drivers/gpu/drm/radeon/radeon_agp.c:136). 131 uint32_t agp_status;
> > 132 int default_mode;
> > 133 bool is_v3;
> > 134 int ret;
> > 135
> > 136 if (rdev->ddev->agp->agp_info.aper_size < 32) {
> > 137 dev_warn(rdev->dev, "AGP aperture to small (%dM) "
> > 138 "need at least 32M, disabling AGP\n",
> > 139 rdev->ddev->agp->agp_info.aper_size);
> > 140 return -EINVAL;
> >
> > Is there any other info I can provide?
>
> In your crash 'rdev->ddev->agp' is NULL. The instruction decode is:
>
> e: 55 push %rbp
> f: 48 89 e5 mov %rsp,%rbp
> 12: 41 56 push %r14
> 14: 41 55 push %r13
> 16: 41 54 push %r12
> 18: 53 push %rbx
> 19: 48 89 fb mov %rdi,%rbx
> 1c: 48 83 ec 40 sub $0x40,%rsp
> 20: 48 8b 7f 08 mov 0x8(%rdi),%rdi
> 24: 48 8b 87 20 03 00 00 mov 0x320(%rdi),%rax
> 2b:* 4c 8b 60 28 mov 0x28(%rax),%r12 <-- trapping
> instruction 2f: 49 83 fc 1f cmp $0x1f,%r12
> 33: 77 2e ja 0x63
> 35: 48 8b 3b mov (%rbx),%rdi
> 38: 48 8b 5f 10 mov 0x10(%rdi),%rbx
>
> so it's that lod of "agp_info.aper_size" that fails (you can see how it's
> trying to compare with 31, it comes from that "agp_info.aper_size < 32"
> thing.
>
> Did that DRM init happen before AGP init or something?
>
> Linus

This is caused by commit 42590a75019a50012f25a962246498dead42843

Fix is already posted:

http://marc.info/?l=linux-kernel&m=126428141429200&w=2
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