BISECTED- amd-staging-drm-next, xorg-server segfault A6-6310 APU - R4 Mullins.

[Michel Dänzer]

On 2019-01-10 10:44 a.m., Przemek Socha wrote:
> Hi,
> after yesterday's fetch of amd-staging-drm-next tree from agd5f git repo my 
> xorg server is segfaulting when starting up.
> 
> I am using gentoo ~amd64, xorg-server 1.20.3, xf86-video-amdgpu-18.1.0. 
> Machine is an old Lenovo g50-45 netbook with A6-6310 APU - R4 Mullins.
> 
> - excerpt from Xorg.log:
> 
> "[    21.878] (II) AMDGPU(0): Setting screen physical size to 700 x 270
> [    21.880] (EE) 
> [    21.880] (EE) Backtrace:
> [    21.880] (EE) 0: /usr/bin/X (xorg_backtrace+0x4d) [0x559df051f0bd]
> [    21.880] (EE) 1: /usr/bin/X (0x559df0376000+0x1acc89) [0x559df0522c89]
> [    21.880] (EE) 2: /lib64/libpthread.so.0 (0x7f6f2edad000+0x14560) 
> [0x7f6f2edc1560]
> [    21.880] (EE) 3: /usr/lib64/xorg/modules/drivers/amdgpu_drv.so 
> (0x7f6f2f32b000+0x14fce) [0x7f6f2f33ffce]
> [    21.880] (EE) 4: /usr/lib64/xorg/modules/drivers/amdgpu_drv.so 
> (0x7f6f2f32b000+0xd1c4) [0x7f6f2f3381c4]
> [    21.880] (EE) 5: /usr/bin/X (0x559df0376000+0xdf024) [0x559df0455024]
> [    21.881] (EE) 6: /usr/bin/X (InitRootWindow+0x11) [0x559df03f8761]
> [    21.881] (EE) 7: /usr/bin/X (0x559df0376000+0x5b574) [0x559df03d1574]
> [    21.881] (EE) 8: /lib64/libc.so.6 (__libc_start_main+0xee) 
> [0x7f6f2ec054ce]
> [    21.881] (EE) 9: /usr/bin/X (_start+0x2a) [0x559df03bb00a]
> [    21.881] (EE) 
> [    21.881] (EE) Segmentation fault at address 0x4
> [    21.881] (EE) 
> Fatal server error:
> [    21.881] (EE) Caught signal 11 (Segmentation fault). Server aborting
> [    21.881] (EE) 
> [    21.881] (EE) 
> Please consult the The X.Org Foundation support 
> 	 at http://wiki.x.org
>  for help. 
> [    21.881] (EE) Please also check the log file at "/var/log/Xorg.0.log" for 
> additional information.
> [    21.881] (EE) 
> [    21.881] (II) AIGLX: Suspending AIGLX clients for VT switch
> [    21.957] (EE) Server terminated with error (1). Closing log file."
> 
> 
> I am not sure if I didn't mess up anything, but git bisect gives the results:
> 
> [...]
> 
> 79c6b898011958fba7722528d567b64e1cdc8dbe is the first bad commit
> commit 79c6b898011958fba7722528d567b64e1cdc8dbe
> Author: Yu Zhao <yuzhao at google.com>
> Date:   Mon Jan 7 15:51:14 2019 -0700
> 
>     drm/amdgpu: validate user pitch alignment
>     
>     Userspace may request pitch alignment that is not supported by GPU.
>     Some requests 32, but GPU ignores it and uses default 64 when cpp is
>     4. If GEM object is allocated based on the smaller alignment, GPU
>     DMA will go out of bound.
>     
>     Cc: stable at vger.kernel.org # v4.2+
>     Reviewed-by: Michel Dänzer <michel.daenzer at amd.com>
>     Signed-off-by: Yu Zhao <yuzhao at google.com>
> 
> :040000 040000 5338964e9975e461ceedb27f6342c2896f54607a 
> ed2f04fc9b665b27b1905fd60b7d2a3933d1fdcc M      drivers

Thanks for tracking this down. It turns out the check added by this
change is too strict for linear framebuffers. I've sent a patch
reverting it for review: https://patchwork.freedesktop.org/patch/276122/

Sorry I didn't realize this issue when reviewing this change.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer

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