Messages in this thread Patch in this message | | | Date | Fri, 30 Sep 2022 18:38:41 -0400 | From | Steven J Abner <> | Subject | Re: [RFC PATCH 1/1] drm/amdgpu: Fix null-ptr-deref in amdgpu_device_fini_sw() |
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I had done more delving into this also, thankfully was not forgotten. Additional info to solve blackout, was going to contact AMD: The problem as far as I could trace occurs in amdgpu_psp.c in function psp_cmd_submit_buf(). Normal counter 'timeout' seems to use a max of about 400 with usleep_range(5, 80). Under normal operation 'psp->fence_buf' will equal 'index' and drop from loop. I could not track what fills the kernel buffer objects 'virtual' pointer's reference (psp->fence_buf). I assume that it's to a firmware file that on read is returning an error, and getting stuck in a loop lock. The error condition I found occurs when 'psp->fence_buf' does not equal 'index', breaking from loop with 'timeout' == 0. Blackout seemed to be about 80% of reboots, but found that in reconfiguration of kernel, on 5.18.19, with CONFIG_ATA_ACPI=y drops blackouts to about 30% of reboots. I have now avoided all blackouts with addition of CONFIG_SATA_PMP=y (at least a week free?). This is pure guess but, maybe the ARM PSP processor is dependent on libata procedures, one of which causes a lock up some of the time. Steve
On Fri, Sep 30, 2022 at 21:41, Zhang Boyang <zhangboyang.id@gmail.com> wrote: > After amdgpu_device_init() failed, adev->reset_domain may be NULL. > Thus > subsequent call to amdgpu_device_fini_sw() may result in > null-ptr-deref. > > This patch fixes the problem by adding a NULL pointer check around the > code of releasing adev->reset_domain in amdgpu_device_fini_sw(). > > Fixes: cfbb6b004744 ("drm/amdgpu: Rework reset domain to be > refcounted.") > > Signed-off-by: Zhang Boyang <zhangboyang.id@gmail.com> > Link: > https://lore.kernel.org/lkml/a8bce489-8ccc-aa95-3de6-f854e03ad557@suddenlinkmail.com/ > Link: https://lore.kernel.org/lkml/AT9WHR.3Z1T3VI9A2AQ3@att.net/ > --- > drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c > b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c > index be7aff2d4a57..204daad06b32 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c > @@ -4021,8 +4021,10 @@ void amdgpu_device_fini_sw(struct > amdgpu_device *adev) > if (adev->mman.discovery_bin) > amdgpu_discovery_fini(adev); > > - amdgpu_reset_put_reset_domain(adev->reset_domain); > - adev->reset_domain = NULL; > + if (adev->reset_domain) { > + amdgpu_reset_put_reset_domain(adev->reset_domain); > + adev->reset_domain = NULL; > + } > > kfree(adev->pci_state); > > -- > 2.30.2 >
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