Re: [PATCH] drm/radeon/ttm: Fix memory leak userptr pages

Christian König
2021-04-07T09:27:19Z

Am 07.04.21 um 09:47 schrieb Daniel Gomez:
> On Tue, 6 Apr 2021 at 22:56, Alex Deucher <alexdeucher@gmail.com> wrote:
>> On Mon, Mar 22, 2021 at 6:34 AM Christian König
>> <ckoenig.leichtzumerken@gmail.com> wrote:
>>> Hi Daniel,
>>>
>>> Am 22.03.21 um 10:38 schrieb Daniel Gomez:
>>>> On Fri, 19 Mar 2021 at 21:29, Felix Kuehling <felix.kuehling@amd.com> wrote:
>>>>> This caused a regression in kfdtest in a large-buffer stress test after
>>>>> memory allocation for user pages fails:
>>>> I'm sorry to hear that. BTW, I guess you meant amdgpu leak patch and
>>>> not this one.
>>>> Just some background for the mem leak patch if helps to understand this:
>>>> The leak was introduce here:
>>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git%2Fcommit%2F%3Fid%3D0b988ca1c7c4c73983b4ea96ef7c2af2263c87eb&amp;data=04%7C01%7CChristian.Koenig%40amd.com%7C65d21b6f02da409ac7b508d8f9997367%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637533784761980218%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=%2FeOQf12NBkC3YGZ7QW66%2FT%2FpyM3DjEb9IMbqUvISMfo%3D&amp;reserved=0
>>>> where the bound status was introduced for all drm drivers including
>>>> radeon and amdgpu. So this patch just reverts the logic to the
>>>> original code but keeping the bound status. In my case, the binding
>>>> code allocates the user pages memory and returns without bounding (at
>>>> amdgpu_gtt_mgr_has_gart_addr). So,
>>>> when the unbinding happens, the memory needs to be cleared to prevent the leak.
>>> Ah, now I understand what's happening here. Daniel your patch is not
>>> really correct.
>>>
>>> The problem is rather that we don't set the tt object to bound if it
>>> doesn't have a GTT address.
>>>
>>> Going to provide a patch for this.
>> Did this patch ever land?
> I don't think so but I might send a v2 following Christian's comment
> if you guys agree.

Somebody else already provided a patch which I reviewed, but I'm not
sure if that landed either.

> Also, the patch here is for radeon but the pagefault issue reported by
> Felix is affected by the amdgpu one:
>
> radeon patch: drm/radeon/ttm: Fix memory leak userptr pages
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.kernel.org%2Fproject%2Fdri-devel%2Fpatch%2F20210318083236.43578-1-daniel%40qtec.com%2F&amp;data=04%7C01%7CChristian.Koenig%40amd.com%7C65d21b6f02da409ac7b508d8f9997367%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637533784761980218%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=HSMK%2FqYz%2Bzz9qbKc%2FITUWluBDeaW9YrgyH8p0L640%2F0%3D&amp;reserved=0
>
> amdgpu patch: drm/amdgpu/ttm: Fix memory leak userptr pages
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.kernel.org%2Fproject%2Fdri-devel%2Fpatch%2F20210317160840.36019-1-daniel%40qtec.com%2F&amp;data=04%7C01%7CChristian.Koenig%40amd.com%7C65d21b6f02da409ac7b508d8f9997367%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637533784761980218%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=UsUZ4YjCSjHmzlPB07oTaGrsntTrQSwlGk%2BxUjwDiag%3D&amp;reserved=0
>
> I assume both need to be fixed with the same approach.

Yes correct. Let me double check where that fix went.

Thanks,
Christian.

>
> Daniel
>> Alex
>>
>>> Regards,
>>> Christian.
>>>
>>>>> [17359.536303] amdgpu: init_user_pages: Failed to get user pages: -16
>>>>> [17359.543746] BUG: kernel NULL pointer dereference, address: 0000000000000000
>>>>> [17359.551494] #PF: supervisor read access in kernel mode
>>>>> [17359.557375] #PF: error_code(0x0000) - not-present page
>>>>> [17359.563247] PGD 0 P4D 0
>>>>> [17359.566514] Oops: 0000 [#1] SMP PTI
>>>>> [17359.570728] CPU: 8 PID: 5944 Comm: kfdtest Not tainted 5.11.0-kfd-fkuehlin #193
>>>>> [17359.578760] Hardware name: ASUS All Series/X99-E WS/USB 3.1, BIOS 3201 06/17/2016
>>>>> [17359.586971] RIP: 0010:amdgpu_ttm_backend_unbind+0x52/0x110 [amdgpu]
>>>>> [17359.594075] Code: 48 39 c6 74 1b 8b 53 0c 48 8d bd 80 a1 ff ff e8 24 62 00 00 85 c0 0f 85 ab 00 00 00 c6 43 54 00 5b 5d c3 48 8b 46 10 8b 4e 50 <48> 8b 30 48 85 f6 74 ba 8b 50 0c 48 8b bf 80 a1 ff ff 83 e1 01 45
>>>>> [17359.614340] RSP: 0018:ffffa4764971fc98 EFLAGS: 00010206
>>>>> [17359.620315] RAX: 0000000000000000 RBX: ffff950e8d4edf00 RCX: 0000000000000000
>>>>> [17359.628204] RDX: 0000000000000000 RSI: ffff950e8d4edf00 RDI: ffff950eadec5e80
>>>>> [17359.636084] RBP: ffff950eadec5e80 R08: 0000000000000000 R09: 0000000000000000
>>>>> [17359.643958] R10: 0000000000000246 R11: 0000000000000001 R12: ffff950c03377800
>>>>> [17359.651833] R13: ffff950eadec5e80 R14: ffff950c03377858 R15: 0000000000000000
>>>>> [17359.659701] FS: 00007febb20cb740(0000) GS:ffff950ebfc00000(0000) knlGS:0000000000000000
>>>>> [17359.668528] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>>> [17359.675012] CR2: 0000000000000000 CR3: 00000006d700e005 CR4: 00000000001706e0
>>>>> [17359.682883] Call Trace:
>>>>> [17359.686063] amdgpu_ttm_backend_destroy+0x12/0x70 [amdgpu]
>>>>> [17359.692349] ttm_bo_cleanup_memtype_use+0x37/0x60 [ttm]
>>>>> [17359.698307] ttm_bo_release+0x278/0x5e0 [ttm]
>>>>> [17359.703385] amdgpu_bo_unref+0x1a/0x30 [amdgpu]
>>>>> [17359.708701] amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x7e5/0x910 [amdgpu]
>>>>> [17359.716307] kfd_ioctl_alloc_memory_of_gpu+0x11a/0x220 [amdgpu]
>>>>> [17359.723036] kfd_ioctl+0x223/0x400 [amdgpu]
>>>>> [17359.728017] ? kfd_dev_is_large_bar+0x90/0x90 [amdgpu]
>>>>> [17359.734152] __x64_sys_ioctl+0x8b/0xd0
>>>>> [17359.738796] do_syscall_64+0x2d/0x40
>>>>> [17359.743259] entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>>>> [17359.749205] RIP: 0033:0x7febb083b6d7
>>>>> [17359.753681] Code: b3 66 90 48 8b 05 b1 47 2d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 81 47 2d 00 f7 d8 64 89 01 48
>>>>> [17359.774340] RSP: 002b:00007ffdb5522cd8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
>>>>> [17359.782668] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007febb083b6d7
>>>>> [17359.790566] RDX: 00007ffdb5522d60 RSI: 00000000c0284b16 RDI: 0000000000000003
>>>>> [17359.798459] RBP: 00007ffdb5522d10 R08: 00007ffdb5522dd0 R09: 00000000c4000004
>>>>> [17359.806352] R10: 0000000000000000 R11: 0000000000000202 R12: 0000559416e4e2aa
>>>>> [17359.814251] R13: 0000000000000000 R14: 0000000000000021 R15: 0000000000000000
>>>>> [17359.822140] Modules linked in: ip6table_filter ip6_tables iptable_filter amdgpu x86_pkg_temp_thermal drm_ttm_helper ttm iommu_v2 gpu_sched ip_tables x_tables
>>>>> [17359.837776] CR2: 0000000000000000
>>>>> [17359.841888] ---[ end trace a6f27d64475b28c8 ]---
>>>>> [17359.847318] RIP: 0010:amdgpu_ttm_backend_unbind+0x52/0x110 [amdgpu]
>>>>> [17359.854479] Code: 48 39 c6 74 1b 8b 53 0c 48 8d bd 80 a1 ff ff e8 24 62 00 00 85 c0 0f 85 ab 00 00 00 c6 43 54 00 5b 5d c3 48 8b 46 10 8b 4e 50 <48> 8b 30 48 85 f6 74 ba 8b 50 0c 48 8b bf 80 a1 ff ff 83 e1 01 45
>>>>> [17359.874929] RSP: 0018:ffffa4764971fc98 EFLAGS: 00010206
>>>>> [17359.881014] RAX: 0000000000000000 RBX: ffff950e8d4edf00 RCX: 0000000000000000
>>>>> [17359.889007] RDX: 0000000000000000 RSI: ffff950e8d4edf00 RDI: ffff950eadec5e80
>>>>> [17359.897008] RBP: ffff950eadec5e80 R08: 0000000000000000 R09: 0000000000000000
>>>>> [17359.905020] R10: 0000000000000246 R11: 0000000000000001 R12: ffff950c03377800
>>>>> [17359.913034] R13: ffff950eadec5e80 R14: ffff950c03377858 R15: 0000000000000000
>>>>> [17359.921050] FS: 00007febb20cb740(0000) GS:ffff950ebfc00000(0000) knlGS:0000000000000000
>>>>> [17359.930047] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>>> [17359.936674] CR2: 0000000000000000 CR3: 00000006d700e005 CR4: 00000000001706e0
>>>> From what I understand, the init_user_pages fails (returns EBUSY) and
>>>> the code goes to allocate_init_user_pages_failed where the unbind and
>>>> the userptr clear occurs.
>>>> Can we prevent this if we save the bounding status + userptr alloc? so
>>>> the function amdgpu_ttm_backend_unbind returns without trying to clear
>>>> the userptr memory?
>>>>
>>>> Something like:
>>>>
>>>> amdgpu_ttm_backend_bind:
>>>> if (gtt->userptr) {
>>>> r = amdgpu_ttm_tt_pin_userptr(bdev, ttm);
>>>> if (r) ...
>>>> gtt->sg_table = true;
>>>> }
>>>>
>>>> amdgpu_ttm_backend_unbind:
>>>> if (gtt->sg_table) {
>>>> if (gtt->user_ptr) ...
>>>> }
>>>>
>>>> If you agree, I'll send a v2 patch. Otherwise, maybe we could return
>>>> within amdgpu_ttm_tt_unpin_userptr if memory hasn't been allocated.
>>>>
>>>> Any other ideas?
>>>>
>>>> Regards,
>>>> Daniel
>>>>
>>>>> Reverting this patch fixes the problem for me.
>>>>>
>>>>> Regards,
>>>>> Felix
>>>>>
>>>>> On 2021-03-18 10:57 p.m., Alex Deucher wrote:
>>>>>> Applied. Thanks!
>>>>>>
>>>>>> Alex
>>>>>>
>>>>>> On Thu, Mar 18, 2021 at 5:00 AM Koenig, Christian
>>>>>> <Christian.Koenig@amd.com> wrote:
>>>>>>> Reviewed-by: Christian König <christian.koenig@amd.com>
>>>>>>> ________________________________
>>>>>>> Von: Daniel Gomez <daniel@qtec.com>
>>>>>>> Gesendet: Donnerstag, 18. März 2021 09:32
>>>>>>> Cc: dagmcr@gmail.com <dagmcr@gmail.com>; Daniel Gomez <daniel@qtec.com>; Deucher, Alexander <Alexander.Deucher@amd.com>; Koenig, Christian <Christian.Koenig@amd.com>; David Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; amd-gfx@lists.freedesktop.org <amd-gfx@lists.freedesktop.org>; dri-devel@lists.freedesktop.org <dri-devel@lists.freedesktop.org>; linux-kernel@vger.kernel.org <linux-kernel@vger.kernel.org>
>>>>>>> Betreff: [PATCH] drm/radeon/ttm: Fix memory leak userptr pages
>>>>>>>
>>>>>>> If userptr pages have been pinned but not bounded,
>>>>>>> they remain uncleared.
>>>>>>>
>>>>>>> Signed-off-by: Daniel Gomez <daniel@qtec.com>
>>>>>>> ---
>>>>>>> drivers/gpu/drm/radeon/radeon_ttm.c | 5 +++--
>>>>>>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
>>>>>>> index e8c66d10478f..bbcc6264d48f 100644
>>>>>>> --- a/drivers/gpu/drm/radeon/radeon_ttm.c
>>>>>>> +++ b/drivers/gpu/drm/radeon/radeon_ttm.c
>>>>>>> @@ -485,13 +485,14 @@ static void radeon_ttm_backend_unbind(struct ttm_bo_device *bdev, struct ttm_tt
>>>>>>> struct radeon_ttm_tt *gtt = (void *)ttm;
>>>>>>> struct radeon_device *rdev = radeon_get_rdev(bdev);
>>>>>>>
>>>>>>> + if (gtt->userptr)
>>>>>>> + radeon_ttm_tt_unpin_userptr(bdev, ttm);
>>>>>>> +
>>>>>>> if (!gtt->bound)
>>>>>>> return;
>>>>>>>
>>>>>>> radeon_gart_unbind(rdev, gtt->offset, ttm->num_pages);
>>>>>>>
>>>>>>> - if (gtt->userptr)
>>>>>>> - radeon_ttm_tt_unpin_userptr(bdev, ttm);
>>>>>>> gtt->bound = false;
>>>>>>> }
>>>>>>>
>>>>>>> --
>>>>>>> 2.30.2
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> dri-devel mailing list
>>>>>>> dri-devel@lists.freedesktop.org
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