[PATCH] drm/amdkfd: fix null pointer panic while free buffer in kfd

[Huang Rui]

On Mon, Feb 01, 2021 at 10:25:36PM +0800, Kuehling, Felix wrote:
> Thank you for catching this. I haven't had a chance to try out Alex's
> rebased branch myself yet. I think this needs a
> 
>     Fixes: 246cb7e49a70 ("drm/amdgpu: Introduce GEM object functions")
> 
> With that fixed, the patch is
> 
> Reviewed-by: Felix Kuehling <Felix.Kuehling at amd.com>
> 
> The fix also needs to go upstream as KFD seems to be very broken without it.

Thanks, will add the description and push into 5.11 drm-next. 

Ray

> 
> Regards,
>   Felix
> 
> Am 2021-02-01 um 5:39 a.m. schrieb Huang Rui:
> > In drm_gem_object_free, it will call funcs of drm buffer obj. So
> > kfd_alloc should use amdgpu_gem_object_create instead of
> > amdgpu_bo_create to initialize the funcs as amdgpu_gem_object_funcs.
> >
> > [  396.231390] amdgpu: Release VA 0x7f76b4ada000 - 0x7f76b4add000
> > [  396.231394] amdgpu:   remove VA 0x7f76b4ada000 - 0x7f76b4add000 in entry 0000000085c24a47
> > [  396.231408] BUG: kernel NULL pointer dereference, address: 0000000000000000
> > [  396.231445] #PF: supervisor read access in kernel mode
> > [  396.231466] #PF: error_code(0x0000) - not-present page
> > [  396.231484] PGD 0 P4D 0
> > [  396.231495] Oops: 0000 [#1] SMP NOPTI
> > [  396.231509] CPU: 7 PID: 1352 Comm: clinfo Tainted: G           OE     5.11.0-rc2-custom #1
> > [  396.231537] Hardware name: AMD Celadon-RN/Celadon-RN, BIOS WCD0401N_Weekly_20_04_0 04/01/2020
> > [  396.231563] RIP: 0010:drm_gem_object_free+0xc/0x22 [drm]
> > [  396.231606] Code: eb ec 48 89 c3 eb e7 0f 1f 44 00 00 55 48 89 e5 48 8b bf 00 06 00 00 e8 72 0d 01 00 5d c3 0f 1f 44 00 00 48 8b 87 40 01 00 00 <48> 8b 00 48 85 c0 74 0b 55 48 89 e5 e8 54 37 7c db 5d c3 0f 0b c3
> > [  396.231666] RSP: 0018:ffffb4704177fcf8 EFLAGS: 00010246
> > [  396.231686] RAX: 0000000000000000 RBX: ffff993a0d0cc400 RCX: 0000000000003113
> > [  396.231711] RDX: 0000000000000001 RSI: e9cda7a5d0791c6d RDI: ffff993a333a9058
> > [  396.231736] RBP: ffffb4704177fdd0 R08: ffff993a03855858 R09: 0000000000000000
> > [  396.231761] R10: ffff993a0d1f7158 R11: 0000000000000001 R12: 0000000000000000
> > [  396.231785] R13: ffff993a0d0cc428 R14: 0000000000003000 R15: ffffb4704177fde0
> > [  396.231811] FS:  00007f76b5730740(0000) GS:ffff993b275c0000(0000) knlGS:0000000000000000
> > [  396.231840] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [  396.231860] CR2: 0000000000000000 CR3: 000000016d2e2000 CR4: 0000000000350ee0
> > [  396.231885] Call Trace:
> > [  396.231897]  ? amdgpu_amdkfd_gpuvm_free_memory_of_gpu+0x24c/0x25f [amdgpu]
> > [  396.232056]  ? __dynamic_dev_dbg+0xcd/0x100
> > [  396.232076]  kfd_ioctl_free_memory_of_gpu+0x91/0x102 [amdgpu]
> > [  396.232214]  kfd_ioctl+0x211/0x35b [amdgpu]
> > [  396.232341]  ? kfd_ioctl_get_queue_wave_state+0x52/0x52 [amdgpu]
> >
> > Signed-off-by: Huang Rui <ray.huang at amd.com>
> > ---
> >
> > This patch is to fix the issue on latest 5.11-rc2 based amd-staging-drm-next.
> >
> > ---
> >  drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 ++++++----------
> >  1 file changed, 6 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> > index 0849b68e784f..ac0a432a9bf7 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> > @@ -26,6 +26,7 @@
> >  #include <linux/sched/task.h>
> >  
> >  #include "amdgpu_object.h"
> > +#include "amdgpu_gem.h"
> >  #include "amdgpu_vm.h"
> >  #include "amdgpu_amdkfd.h"
> >  #include "amdgpu_dma_buf.h"
> > @@ -1152,7 +1153,7 @@ int amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu(
> >  	struct sg_table *sg = NULL;
> >  	uint64_t user_addr = 0;
> >  	struct amdgpu_bo *bo;
> > -	struct amdgpu_bo_param bp;
> > +	struct drm_gem_object *gobj;
> >  	u32 domain, alloc_domain;
> >  	u64 alloc_flags;
> >  	int ret;
> > @@ -1220,19 +1221,14 @@ int amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu(
> >  	pr_debug("\tcreate BO VA 0x%llx size 0x%llx domain %s\n",
> >  			va, size, domain_string(alloc_domain));
> >  
> > -	memset(&bp, 0, sizeof(bp));
> > -	bp.size = size;
> > -	bp.byte_align = 1;
> > -	bp.domain = alloc_domain;
> > -	bp.flags = alloc_flags;
> > -	bp.type = bo_type;
> > -	bp.resv = NULL;
> > -	ret = amdgpu_bo_create(adev, &bp, &bo);
> > +	ret = amdgpu_gem_object_create(adev, size, 1, alloc_domain, alloc_flags,
> > +				       bo_type, NULL, &gobj);
> >  	if (ret) {
> >  		pr_debug("Failed to create BO on domain %s. ret %d\n",
> > -				domain_string(alloc_domain), ret);
> > +			 domain_string(alloc_domain), ret);
> >  		goto err_bo_create;
> >  	}
> > +	bo = gem_to_amdgpu_bo(gobj);
> >  	if (bo_type == ttm_bo_type_sg) {
> >  		bo->tbo.sg = sg;
> >  		bo->tbo.ttm->sg = sg;