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

Alex Deucher
2021-04-06T20:56:16Z

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://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0b988ca1c7c4c73983b4ea96ef7c2af2263c87eb
> > 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?

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
> >>>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
> >>> _______________________________________________
> >>> dri-devel mailing list
> >>> dri-devel@lists.freedesktop.org
> >>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
> > _______________________________________________
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> > amd-gfx@lists.freedesktop.org
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>