Messages in this thread | | | Subject | Re: [PATCH] drm/radeon: don't add files at control minor debugfs directory | From | Christian König <> | Date | Mon, 5 Dec 2016 09:48:02 +0100 |
| |
Am 05.12.2016 um 09:39 schrieb Nicolai Stange: > Christian König <christian.koenig@amd.com> writes: > >> Am 05.12.2016 um 08:27 schrieb Daniel Vetter: >>> On Sat, Dec 03, 2016 at 03:47:00PM +0100, Nicolai Stange wrote: >>>> Since commit 8a357d10043c ("drm: Nerf DRM_CONTROL nodes"), a >>>> struct drm_device's ->control member is always NULL. >>>> >>>> In the case of CONFIG_DEBUG_FS=y, radeon_debugfs_add_files() accesses >>>> ->control->debugfs_root though. This results in the following Oops: >>>> >>>> BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 >>>> IP: radeon_debugfs_add_files+0x90/0x100 [radeon] >>>> PGD 0 >>>> Oops: 0000 [#1] SMP >>>> [...] >>>> Call Trace: >>>> ? work_on_cpu+0xb0/0xb0 >>>> radeon_fence_driver_init+0x120/0x150 [radeon] >>>> si_init+0x122/0xd50 [radeon] >>>> ? _raw_spin_unlock_irq+0x2c/0x40 >>>> ? device_pm_check_callbacks+0xb3/0xc0 >>>> radeon_device_init+0x958/0xda0 [radeon] >>>> radeon_driver_load_kms+0x9a/0x210 [radeon] >>>> drm_dev_register+0xa9/0xd0 [drm] >>>> drm_get_pci_dev+0x9c/0x1e0 [drm] >>>> radeon_pci_probe+0xb8/0xe0 [radeon] >>>> [...] >>>> >>>> Fix this by omitting the drm_debugfs_create_files() call for the >>>> control minor debugfs directory which is now non-existent anyway. >>>> >>>> Fixes: 8a357d10043c ("drm: Nerf DRM_CONTROL nodes") >>>> Signed-off-by: Nicolai Stange <nicstange@gmail.com> >>> Applied to drm-misc with Dave's irc ack, thanks for your patch. >> If it's still worth it the patch is Reviewed-by: Christian König >> <christian.koenig@amd.com>. >> >> On the other hand when ->control is always NULL, why do we still have >> ->control anyway? > Yes, I was wondering about that, too. > > Quoting from 8a357d10043c ("drm: Nerf DRM_CONTROL nodes"): > > Since I don't like dead uabi, let's remove it. But since this would be > a really big change I think it's better to start out small by simply > not registering anything. We can garbage-collect the dead code later > on, once we're sure it's really not used anywhere. > > I'd too prefer compile time errors by purging ->control here. Daniel?
Seconded.
> > >> And BTW: Please double check the other drivers as well. > # git grep '\->control' -- drivers/gpu/ > drivers/gpu/drm/amd/amdgpu/amdgpu_device.c: adev->ddev->control->debugfs_root, > drivers/gpu/drm/amd/amdgpu/amdgpu_device.c: adev->ddev->control); > drivers/gpu/drm/amd/amdgpu/amdgpu_device.c: adev->ddev->control); > > Oops.
Yeah, that's what I expected as well but Daniel said it would only affect qxl.
> > drivers/gpu/drm/amd/amdkfd/kfd_dbgdev.c: ib_packet->control = (1 << 23) | (1 << 31) | > drivers/gpu/drm/drm_drv.c: return &dev->control; > > That's drm_minor_get_slot(dev, type), but grepping for DRM_MINOR_CONTROL > doesn't yield anything -> dead code. > > drivers/gpu/drm/gma500/psb_intel_sdvo.c: switch (sdvo->controlled_output) { > drivers/gpu/drm/gma500/psb_intel_sdvo.c: psb_intel_sdvo->controlled_output |= SDVO_OUTPUT_TMDS0; > drivers/gpu/drm/gma500/psb_intel_sdvo.c: psb_intel_sdvo->controlled_output |= SDVO_OUTPUT_TMDS1; > drivers/gpu/drm/gma500/psb_intel_sdvo.c: psb_intel_sdvo->controlled_output |= type; > drivers/gpu/drm/gma500/psb_intel_sdvo.c: psb_intel_sdvo->controlled_output |= SDVO_OUTPUT_RGB0; > drivers/gpu/drm/gma500/psb_intel_sdvo.c: psb_intel_sdvo->controlled_output |= SDVO_OUTPUT_RGB1; > drivers/gpu/drm/gma500/psb_intel_sdvo.c: psb_intel_sdvo->controlled_output |= SDVO_OUTPUT_LVDS0; > drivers/gpu/drm/gma500/psb_intel_sdvo.c: psb_intel_sdvo->controlled_output |= SDVO_OUTPUT_LVDS1; > drivers/gpu/drm/gma500/psb_intel_sdvo.c: psb_intel_sdvo->controlled_output = 0; > drivers/gpu/drm/i915/intel_sdvo.c: switch (sdvo->controlled_output) { > drivers/gpu/drm/i915/intel_sdvo.c: intel_sdvo->controlled_output |= SDVO_OUTPUT_TMDS0; > drivers/gpu/drm/i915/intel_sdvo.c: intel_sdvo->controlled_output |= SDVO_OUTPUT_TMDS1; > drivers/gpu/drm/i915/intel_sdvo.c: intel_sdvo->controlled_output |= type; > drivers/gpu/drm/i915/intel_sdvo.c: intel_sdvo->controlled_output |= SDVO_OUTPUT_RGB0; > drivers/gpu/drm/i915/intel_sdvo.c: intel_sdvo->controlled_output |= SDVO_OUTPUT_RGB1; > drivers/gpu/drm/i915/intel_sdvo.c: intel_sdvo->controlled_output |= SDVO_OUTPUT_LVDS0; > drivers/gpu/drm/i915/intel_sdvo.c: intel_sdvo->controlled_output |= SDVO_OUTPUT_LVDS1; > drivers/gpu/drm/i915/intel_sdvo.c: intel_sdvo->controlled_output = 0; > drivers/gpu/drm/msm/msm_debugfs.c: ret = late_init_minor(dev->control); > > Not an oops but dead code. > > drivers/gpu/drm/qxl/qxl_debugfs.c: qdev->ddev->control->debugfs_root, > drivers/gpu/drm/qxl/qxl_debugfs.c: qdev->ddev->control); > drivers/gpu/drm/qxl/qxl_debugfs.c: qdev->ddev->control); > > Oops. > > > I'll send compile-only tested patches either tonight or tomorrow. Shall > they cover the oopses only or the dead code as well?
Please start with the ops, cause we certainly will get complains about that rather fast.
Regards, Christian.
> > > Thanks, > > Nicolai
| |