cpu 1 cpu 2 kfd alloc BO A(userptr) alloc BO B(GTT) ->init -> validate -> init -> validate -> populate init_user_pages -> swapout BO A //hit ttm pages limit -> get_user_pages (fill up ttm->pages) -> validate -> populate -> swapin BO A // Now hit the BUG
We know that get_user_pages may race with swapout on same BO. Threre are some issues I have met. 1) memory corruption. This is because we do a swap before memory is setup. ttm_tt_swapout() just create a swap_storage with its content being 0x0. So when we setup memory after the swapout. The following swapin makes the memory corrupted.
2) panic When swapout happes with get_user_pages, they touch ttm->pages without anylock. It causes memory corruption too. But I hit page fault mostly.
Signed-off-by: xinhui pan xinhui.pan@amd.com --- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 928e8d57cd08..42460e4480f8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -835,6 +835,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) struct amdkfd_process_info *process_info = mem->process_info; struct amdgpu_bo *bo = mem->bo; struct ttm_operation_ctx ctx = { true, false }; + struct page **pages; int ret = 0;
mutex_lock(&process_info->lock); @@ -852,7 +853,13 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) goto out; }
- ret = amdgpu_ttm_tt_get_user_pages(bo, bo->tbo.ttm->pages); + pages = kvmalloc_array(bo->tbo.ttm->num_pages, + sizeof(struct page *), + GFP_KERNEL | __GFP_ZERO); + if (!pages) + goto unregister_out; + + ret = amdgpu_ttm_tt_get_user_pages(bo, pages); if (ret) { pr_err("%s: Failed to get user pages: %d\n", __func__, ret); goto unregister_out; @@ -863,6 +870,12 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) pr_err("%s: Failed to reserve BO\n", __func__); goto release_out; } + + WARN_ON_ONCE(bo->tbo.ttm->page_flags & TTM_PAGE_FLAG_SWAPPED); + + memcpy(bo->tbo.ttm->pages, + pages, + sizeof(struct page*) * bo->tbo.ttm->num_pages); amdgpu_bo_placement_from_domain(bo, mem->domain); ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx); if (ret) @@ -872,6 +885,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) release_out: amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm); unregister_out: + kvfree(pages); if (ret) amdgpu_mn_unregister(bo); out:
Signed-off-by: xinhui pan xinhui.pan@amd.com --- drivers/gpu/drm/ttm/ttm_device.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c index 510e3e001dab..a9772fcc8f9c 100644 --- a/drivers/gpu/drm/ttm/ttm_device.c +++ b/drivers/gpu/drm/ttm/ttm_device.c @@ -146,6 +146,7 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx, uint32_t num_pages;
if (!bo->ttm || + !bo->ttm->pages || !bo->ttm->pages[0] || bo->ttm->page_flags & TTM_PAGE_FLAG_SG || bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED) continue;
Am 19.05.21 um 04:28 schrieb xinhui pan:
Signed-off-by: xinhui pan xinhui.pan@amd.com
drivers/gpu/drm/ttm/ttm_device.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c index 510e3e001dab..a9772fcc8f9c 100644 --- a/drivers/gpu/drm/ttm/ttm_device.c +++ b/drivers/gpu/drm/ttm/ttm_device.c @@ -146,6 +146,7 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx, uint32_t num_pages;
if (!bo->ttm ||
!bo->ttm->pages || !bo->ttm->pages[0] ||
This should call ttm_tt_is_populated() instead.
But apart from that it sounds like the right approach to fix this.
Thanks, Christian.
bo->ttm->page_flags & TTM_PAGE_FLAG_SG || bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED) continue;
[AMD Official Use Only]
To observe the issue. I made one kfdtest case for debug. It just alloc a userptr memory and detect if memory is corrupted. I can hit this failure in 2 minutes. :(
diff --git a/tests/kfdtest/src/KFDMemoryTest.cpp b/tests/kfdtest/src/KFDMemoryTest.cpp index 70c8033..a72f53f 100644 --- a/tests/kfdtest/src/KFDMemoryTest.cpp +++ b/tests/kfdtest/src/KFDMemoryTest.cpp @@ -584,6 +584,32 @@ TEST_F(KFDMemoryTest, ZeroMemorySizeAlloc) { TEST_END }
+TEST_F(KFDMemoryTest, swap) { + TEST_START(TESTPROFILE_RUNALL) + + unsigned int size = 128<<20; + unsigned int*tmp = (unsigned int *)mmap(0, + size, + PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, + -1, + 0); + EXPECT_NE(tmp, MAP_FAILED); + + LOG() << "pls run this with KFDMemoryTest.LargestSysBufferTest" << std::endl; + do { + memset(tmp, 0xcc, size); + + HsaMemoryBuffer buf(tmp, size); + sleep(1); + EXPECT_EQ(tmp[0], 0xcccccccc); + } while (true); + + munmap(tmp, size); + + TEST_END +} + // Basic test for hsaKmtAllocMemory TEST_F(KFDMemoryTest, MemoryAlloc) { TEST_START(TESTPROFILE_RUNALL) -- 2.25.1
________________________________________ 发件人: Pan, Xinhui Xinhui.Pan@amd.com 发送时间: 2021年5月19日 10:28 收件人: amd-gfx@lists.freedesktop.org 抄送: Kuehling, Felix; Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch; Pan, Xinhui 主题: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
cpu 1 cpu 2 kfd alloc BO A(userptr) alloc BO B(GTT) ->init -> validate -> init -> validate -> populate init_user_pages -> swapout BO A //hit ttm pages limit -> get_user_pages (fill up ttm->pages) -> validate -> populate -> swapin BO A // Now hit the BUG
We know that get_user_pages may race with swapout on same BO. Threre are some issues I have met. 1) memory corruption. This is because we do a swap before memory is setup. ttm_tt_swapout() just create a swap_storage with its content being 0x0. So when we setup memory after the swapout. The following swapin makes the memory corrupted.
2) panic When swapout happes with get_user_pages, they touch ttm->pages without anylock. It causes memory corruption too. But I hit page fault mostly.
Signed-off-by: xinhui pan xinhui.pan@amd.com --- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 928e8d57cd08..42460e4480f8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -835,6 +835,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) struct amdkfd_process_info *process_info = mem->process_info; struct amdgpu_bo *bo = mem->bo; struct ttm_operation_ctx ctx = { true, false }; + struct page **pages; int ret = 0;
mutex_lock(&process_info->lock); @@ -852,7 +853,13 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) goto out; }
- ret = amdgpu_ttm_tt_get_user_pages(bo, bo->tbo.ttm->pages); + pages = kvmalloc_array(bo->tbo.ttm->num_pages, + sizeof(struct page *), + GFP_KERNEL | __GFP_ZERO); + if (!pages) + goto unregister_out; + + ret = amdgpu_ttm_tt_get_user_pages(bo, pages); if (ret) { pr_err("%s: Failed to get user pages: %d\n", __func__, ret); goto unregister_out; @@ -863,6 +870,12 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) pr_err("%s: Failed to reserve BO\n", __func__); goto release_out; } + + WARN_ON_ONCE(bo->tbo.ttm->page_flags & TTM_PAGE_FLAG_SWAPPED); + + memcpy(bo->tbo.ttm->pages, + pages, + sizeof(struct page*) * bo->tbo.ttm->num_pages); amdgpu_bo_placement_from_domain(bo, mem->domain); ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx); if (ret) @@ -872,6 +885,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) release_out: amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm); unregister_out: + kvfree(pages); if (ret) amdgpu_mn_unregister(bo); out: -- 2.25.1
Swapping SG BOs makes no sense, because TTM doesn't own the pages of this type of BO.
Last I checked, userptr BOs (and other SG BOs) were protected from swapout by the fact that they would not be added to the swap-LRU. But it looks like Christian just removed the swap-LRU. I guess this broke that protection:
commit 2cb51d22d70b18eaf339abf9758bf0b7608da65c Author: Christian König christian.koenig@amd.com Date: Tue Oct 6 16:30:09 2020 +0200
drm/ttm: remove swap LRU v3
Instead evict round robin from each devices SYSTEM and TT domain.
v2: reorder num_pages access reported by Dan's script v3: fix rebase fallout, num_pages should be 32bit
Signed-off-by: Christian König christian.koenig@amd.com Tested-by: Nirmoy Das nirmoy.das@amd.com Reviewed-by: Huang Rui ray.huang@amd.com Reviewed-by: Matthew Auld matthew.auld@intel.com Link: https://patchwork.freedesktop.org/patch/424009/
Regards, Felix
On 2021-05-18 10:28 p.m., xinhui pan wrote:
cpu 1 cpu 2 kfd alloc BO A(userptr) alloc BO B(GTT) ->init -> validate -> init -> validate -> populate init_user_pages -> swapout BO A //hit ttm pages limit -> get_user_pages (fill up ttm->pages) -> validate -> populate -> swapin BO A // Now hit the BUG
We know that get_user_pages may race with swapout on same BO. Threre are some issues I have met.
- memory corruption.
This is because we do a swap before memory is setup. ttm_tt_swapout() just create a swap_storage with its content being 0x0. So when we setup memory after the swapout. The following swapin makes the memory corrupted.
- panic
When swapout happes with get_user_pages, they touch ttm->pages without anylock. It causes memory corruption too. But I hit page fault mostly.
Signed-off-by: xinhui pan xinhui.pan@amd.com
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 928e8d57cd08..42460e4480f8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -835,6 +835,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) struct amdkfd_process_info *process_info = mem->process_info; struct amdgpu_bo *bo = mem->bo; struct ttm_operation_ctx ctx = { true, false };
struct page **pages; int ret = 0;
mutex_lock(&process_info->lock);
@@ -852,7 +853,13 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) goto out; }
- ret = amdgpu_ttm_tt_get_user_pages(bo, bo->tbo.ttm->pages);
- pages = kvmalloc_array(bo->tbo.ttm->num_pages,
sizeof(struct page *),GFP_KERNEL | __GFP_ZERO);- if (!pages)
goto unregister_out;- ret = amdgpu_ttm_tt_get_user_pages(bo, pages); if (ret) { pr_err("%s: Failed to get user pages: %d\n", __func__, ret); goto unregister_out;
@@ -863,6 +870,12 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) pr_err("%s: Failed to reserve BO\n", __func__); goto release_out; }
- WARN_ON_ONCE(bo->tbo.ttm->page_flags & TTM_PAGE_FLAG_SWAPPED);
- memcpy(bo->tbo.ttm->pages,
pages,sizeof(struct page*) * bo->tbo.ttm->num_pages);@@ -872,6 +885,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) release_out: amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm); unregister_out:
- kvfree(pages); if (ret) amdgpu_mn_unregister(bo); out:
[AMD Official Use Only]
yes, we really dont swapout SG BOs. The problems is that before we validate a userptr BO, we create this BO in CPU domain by default. So this BO has chance to swapout.
we set flag TTM_PAGE_FLAG_SG on userptr BO in popluate() which is too late. I have not try to revert Chris' patch as I think it desnt help. Or I can have a try later.
________________________________________ 发件人: Kuehling, Felix Felix.Kuehling@amd.com 发送时间: 2021年5月19日 11:29 收件人: Pan, Xinhui; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: Re: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
Swapping SG BOs makes no sense, because TTM doesn't own the pages of this type of BO.
Last I checked, userptr BOs (and other SG BOs) were protected from swapout by the fact that they would not be added to the swap-LRU. But it looks like Christian just removed the swap-LRU. I guess this broke that protection:
commit 2cb51d22d70b18eaf339abf9758bf0b7608da65c Author: Christian König christian.koenig@amd.com Date: Tue Oct 6 16:30:09 2020 +0200
drm/ttm: remove swap LRU v3
Instead evict round robin from each devices SYSTEM and TT domain.
v2: reorder num_pages access reported by Dan's script v3: fix rebase fallout, num_pages should be 32bit
Signed-off-by: Christian König christian.koenig@amd.com Tested-by: Nirmoy Das nirmoy.das@amd.com Reviewed-by: Huang Rui ray.huang@amd.com Reviewed-by: Matthew Auld matthew.auld@intel.com Link: https://patchwork.freedesktop.org/patch/424009/
Regards, Felix
On 2021-05-18 10:28 p.m., xinhui pan wrote:
cpu 1 cpu 2 kfd alloc BO A(userptr) alloc BO B(GTT) ->init -> validate -> init -> validate -> populate init_user_pages -> swapout BO A //hit ttm pages limit -> get_user_pages (fill up ttm->pages) -> validate -> populate -> swapin BO A // Now hit the BUG
We know that get_user_pages may race with swapout on same BO. Threre are some issues I have met.
- memory corruption.
This is because we do a swap before memory is setup. ttm_tt_swapout() just create a swap_storage with its content being 0x0. So when we setup memory after the swapout. The following swapin makes the memory corrupted.
- panic
When swapout happes with get_user_pages, they touch ttm->pages without anylock. It causes memory corruption too. But I hit page fault mostly.
Signed-off-by: xinhui pan xinhui.pan@amd.com
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 928e8d57cd08..42460e4480f8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -835,6 +835,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) struct amdkfd_process_info *process_info = mem->process_info; struct amdgpu_bo *bo = mem->bo; struct ttm_operation_ctx ctx = { true, false };
struct page **pages; int ret = 0; mutex_lock(&process_info->lock);@@ -852,7 +853,13 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) goto out; }
ret = amdgpu_ttm_tt_get_user_pages(bo, bo->tbo.ttm->pages);
pages = kvmalloc_array(bo->tbo.ttm->num_pages,sizeof(struct page *),GFP_KERNEL | __GFP_ZERO);if (!pages)goto unregister_out;ret = amdgpu_ttm_tt_get_user_pages(bo, pages); if (ret) { pr_err("%s: Failed to get user pages: %d\n", __func__, ret); goto unregister_out;@@ -863,6 +870,12 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) pr_err("%s: Failed to reserve BO\n", __func__); goto release_out; }
WARN_ON_ONCE(bo->tbo.ttm->page_flags & TTM_PAGE_FLAG_SWAPPED);memcpy(bo->tbo.ttm->pages,pages,sizeof(struct page*) * bo->tbo.ttm->num_pages); amdgpu_bo_placement_from_domain(bo, mem->domain); ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx); if (ret)@@ -872,6 +885,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) release_out: amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm); unregister_out:
kvfree(pages); if (ret) amdgpu_mn_unregister(bo);
[AMD Official Use Only]
I have reverted Chris' patch, still hit this failure. Just see two lines in Chris' patch. Any BO in cpu domian would be swapout first. That is why we hit this issue frequently now. But the bug is there long time ago.
- for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) { - list_for_each_entry(bo, &glob->swap_lru[i], swap) { [snip] + for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) { + for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
________________________________________ 发件人: Pan, Xinhui Xinhui.Pan@amd.com 发送时间: 2021年5月19日 12:09 收件人: Kuehling, Felix; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
yes, we really dont swapout SG BOs. The problems is that before we validate a userptr BO, we create this BO in CPU domain by default. So this BO has chance to swapout.
we set flag TTM_PAGE_FLAG_SG on userptr BO in popluate() which is too late. I have not try to revert Chris' patch as I think it desnt help. Or I can have a try later.
________________________________________ 发件人: Kuehling, Felix Felix.Kuehling@amd.com 发送时间: 2021年5月19日 11:29 收件人: Pan, Xinhui; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: Re: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
Swapping SG BOs makes no sense, because TTM doesn't own the pages of this type of BO.
Last I checked, userptr BOs (and other SG BOs) were protected from swapout by the fact that they would not be added to the swap-LRU. But it looks like Christian just removed the swap-LRU. I guess this broke that protection:
commit 2cb51d22d70b18eaf339abf9758bf0b7608da65c Author: Christian König christian.koenig@amd.com Date: Tue Oct 6 16:30:09 2020 +0200
drm/ttm: remove swap LRU v3
Instead evict round robin from each devices SYSTEM and TT domain.
v2: reorder num_pages access reported by Dan's script v3: fix rebase fallout, num_pages should be 32bit
Signed-off-by: Christian König christian.koenig@amd.com Tested-by: Nirmoy Das nirmoy.das@amd.com Reviewed-by: Huang Rui ray.huang@amd.com Reviewed-by: Matthew Auld matthew.auld@intel.com Link: https://patchwork.freedesktop.org/patch/424009/
Regards, Felix
On 2021-05-18 10:28 p.m., xinhui pan wrote:
cpu 1 cpu 2 kfd alloc BO A(userptr) alloc BO B(GTT) ->init -> validate -> init -> validate -> populate init_user_pages -> swapout BO A //hit ttm pages limit -> get_user_pages (fill up ttm->pages) -> validate -> populate -> swapin BO A // Now hit the BUG
We know that get_user_pages may race with swapout on same BO. Threre are some issues I have met.
- memory corruption.
This is because we do a swap before memory is setup. ttm_tt_swapout() just create a swap_storage with its content being 0x0. So when we setup memory after the swapout. The following swapin makes the memory corrupted.
- panic
When swapout happes with get_user_pages, they touch ttm->pages without anylock. It causes memory corruption too. But I hit page fault mostly.
Signed-off-by: xinhui pan xinhui.pan@amd.com
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 928e8d57cd08..42460e4480f8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -835,6 +835,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) struct amdkfd_process_info *process_info = mem->process_info; struct amdgpu_bo *bo = mem->bo; struct ttm_operation_ctx ctx = { true, false };
struct page **pages; int ret = 0; mutex_lock(&process_info->lock);@@ -852,7 +853,13 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) goto out; }
ret = amdgpu_ttm_tt_get_user_pages(bo, bo->tbo.ttm->pages);
pages = kvmalloc_array(bo->tbo.ttm->num_pages,sizeof(struct page *),GFP_KERNEL | __GFP_ZERO);if (!pages)goto unregister_out;ret = amdgpu_ttm_tt_get_user_pages(bo, pages); if (ret) { pr_err("%s: Failed to get user pages: %d\n", __func__, ret); goto unregister_out;@@ -863,6 +870,12 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) pr_err("%s: Failed to reserve BO\n", __func__); goto release_out; }
WARN_ON_ONCE(bo->tbo.ttm->page_flags & TTM_PAGE_FLAG_SWAPPED);memcpy(bo->tbo.ttm->pages,pages,sizeof(struct page*) * bo->tbo.ttm->num_pages); amdgpu_bo_placement_from_domain(bo, mem->domain); ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx); if (ret)@@ -872,6 +885,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) release_out: amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm); unregister_out:
kvfree(pages); if (ret) amdgpu_mn_unregister(bo);
I'm scratching my head how that is even possible.
See when a BO is created in the system domain it is just an empty hull, e.g. without backing store and allocated pages.
So the swapout function will just ignore it.
Christian.
Am 19.05.21 um 07:07 schrieb Pan, Xinhui:
[AMD Official Use Only]
I have reverted Chris' patch, still hit this failure. Just see two lines in Chris' patch. Any BO in cpu domian would be swapout first. That is why we hit this issue frequently now. But the bug is there long time ago.
for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {list_for_each_entry(bo, &glob->swap_lru[i], swap) {[snip]
for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) {for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
发件人: Pan, Xinhui Xinhui.Pan@amd.com 发送时间: 2021年5月19日 12:09 收件人: Kuehling, Felix; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
yes, we really dont swapout SG BOs. The problems is that before we validate a userptr BO, we create this BO in CPU domain by default. So this BO has chance to swapout.
we set flag TTM_PAGE_FLAG_SG on userptr BO in popluate() which is too late. I have not try to revert Chris' patch as I think it desnt help. Or I can have a try later.
发件人: Kuehling, Felix Felix.Kuehling@amd.com 发送时间: 2021年5月19日 11:29 收件人: Pan, Xinhui; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: Re: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
Swapping SG BOs makes no sense, because TTM doesn't own the pages of this type of BO.
Last I checked, userptr BOs (and other SG BOs) were protected from swapout by the fact that they would not be added to the swap-LRU. But it looks like Christian just removed the swap-LRU. I guess this broke that protection:
commit 2cb51d22d70b18eaf339abf9758bf0b7608da65c Author: Christian König christian.koenig@amd.com Date: Tue Oct 6 16:30:09 2020 +0200
drm/ttm: remove swap LRU v3 Instead evict round robin from each devices SYSTEM and TT domain. v2: reorder num_pages access reported by Dan's script v3: fix rebase fallout, num_pages should be 32bit Signed-off-by: Christian König <christian.koenig@amd.com> Tested-by: Nirmoy Das <nirmoy.das@amd.com> Reviewed-by: Huang Rui <ray.huang@amd.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/424009/Regards, Felix
On 2021-05-18 10:28 p.m., xinhui pan wrote:
cpu 1 cpu 2 kfd alloc BO A(userptr) alloc BO B(GTT) ->init -> validate -> init -> validate -> populate init_user_pages -> swapout BO A //hit ttm pages limit -> get_user_pages (fill up ttm->pages) -> validate -> populate -> swapin BO A // Now hit the BUG
We know that get_user_pages may race with swapout on same BO. Threre are some issues I have met.
- memory corruption.
This is because we do a swap before memory is setup. ttm_tt_swapout() just create a swap_storage with its content being 0x0. So when we setup memory after the swapout. The following swapin makes the memory corrupted.
- panic
When swapout happes with get_user_pages, they touch ttm->pages without anylock. It causes memory corruption too. But I hit page fault mostly.
Signed-off-by: xinhui pan xinhui.pan@amd.com
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 928e8d57cd08..42460e4480f8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -835,6 +835,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) struct amdkfd_process_info *process_info = mem->process_info; struct amdgpu_bo *bo = mem->bo; struct ttm_operation_ctx ctx = { true, false };
struct page **pages; int ret = 0; mutex_lock(&process_info->lock);@@ -852,7 +853,13 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) goto out; }
ret = amdgpu_ttm_tt_get_user_pages(bo, bo->tbo.ttm->pages);
pages = kvmalloc_array(bo->tbo.ttm->num_pages,sizeof(struct page *),GFP_KERNEL | __GFP_ZERO);if (!pages)goto unregister_out;ret = amdgpu_ttm_tt_get_user_pages(bo, pages); if (ret) { pr_err("%s: Failed to get user pages: %d\n", __func__, ret); goto unregister_out;@@ -863,6 +870,12 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) pr_err("%s: Failed to reserve BO\n", __func__); goto release_out; }
WARN_ON_ONCE(bo->tbo.ttm->page_flags & TTM_PAGE_FLAG_SWAPPED);memcpy(bo->tbo.ttm->pages,pages,sizeof(struct page*) * bo->tbo.ttm->num_pages); amdgpu_bo_placement_from_domain(bo, mem->domain); ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx); if (ret)@@ -872,6 +885,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) release_out: amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm); unregister_out:
kvfree(pages); if (ret) amdgpu_mn_unregister(bo);
amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx
Looks like we're creating the userptr BO as ttm_bo_type_device. I guess we should be using ttm_bo_type_sg? BTW, amdgpu_gem_userptr_ioctl also uses ttm_bo_type_device.
Regards, Felix
Am 2021-05-19 um 6:01 a.m. schrieb Christian König:
I'm scratching my head how that is even possible.
See when a BO is created in the system domain it is just an empty hull, e.g. without backing store and allocated pages.
So the swapout function will just ignore it.
Christian.
Am 19.05.21 um 07:07 schrieb Pan, Xinhui:
[AMD Official Use Only]
I have reverted Chris' patch, still hit this failure. Just see two lines in Chris' patch. Any BO in cpu domian would be swapout first. That is why we hit this issue frequently now. But the bug is there long time ago.
- for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) { - list_for_each_entry(bo, &glob->swap_lru[i], swap) { [snip] + for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) { + for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
发件人: Pan, Xinhui Xinhui.Pan@amd.com 发送时间: 2021年5月19日 12:09 收件人: Kuehling, Felix; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
yes, we really dont swapout SG BOs. The problems is that before we validate a userptr BO, we create this BO in CPU domain by default. So this BO has chance to swapout.
we set flag TTM_PAGE_FLAG_SG on userptr BO in popluate() which is too late. I have not try to revert Chris' patch as I think it desnt help. Or I can have a try later.
发件人: Kuehling, Felix Felix.Kuehling@amd.com 发送时间: 2021年5月19日 11:29 收件人: Pan, Xinhui; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: Re: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
Swapping SG BOs makes no sense, because TTM doesn't own the pages of this type of BO.
Last I checked, userptr BOs (and other SG BOs) were protected from swapout by the fact that they would not be added to the swap-LRU. But it looks like Christian just removed the swap-LRU. I guess this broke that protection:
commit 2cb51d22d70b18eaf339abf9758bf0b7608da65c Author: Christian König christian.koenig@amd.com Date: Tue Oct 6 16:30:09 2020 +0200
drm/ttm: remove swap LRU v3
Instead evict round robin from each devices SYSTEM and TT domain.
v2: reorder num_pages access reported by Dan's script v3: fix rebase fallout, num_pages should be 32bit
Signed-off-by: Christian König christian.koenig@amd.com Tested-by: Nirmoy Das nirmoy.das@amd.com Reviewed-by: Huang Rui ray.huang@amd.com Reviewed-by: Matthew Auld matthew.auld@intel.com Link: https://patchwork.freedesktop.org/patch/424009/
Regards, Felix
On 2021-05-18 10:28 p.m., xinhui pan wrote:
cpu 1 cpu 2 kfd alloc BO A(userptr) alloc BO B(GTT) ->init -> validate -> init -> validate -> populate init_user_pages -> swapout BO A //hit ttm pages limit -> get_user_pages (fill up ttm->pages) -> validate -> populate -> swapin BO A // Now hit the BUG
We know that get_user_pages may race with swapout on same BO. Threre are some issues I have met.
- memory corruption.
This is because we do a swap before memory is setup. ttm_tt_swapout() just create a swap_storage with its content being 0x0. So when we setup memory after the swapout. The following swapin makes the memory corrupted.
- panic
When swapout happes with get_user_pages, they touch ttm->pages without anylock. It causes memory corruption too. But I hit page fault mostly.
Signed-off-by: xinhui pan xinhui.pan@amd.com
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 928e8d57cd08..42460e4480f8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -835,6 +835,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) struct amdkfd_process_info *process_info = mem->process_info; struct amdgpu_bo *bo = mem->bo; struct ttm_operation_ctx ctx = { true, false }; + struct page **pages; int ret = 0;
mutex_lock(&process_info->lock); @@ -852,7 +853,13 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) goto out; }
- ret = amdgpu_ttm_tt_get_user_pages(bo, bo->tbo.ttm->pages); + pages = kvmalloc_array(bo->tbo.ttm->num_pages, + sizeof(struct page *), + GFP_KERNEL | __GFP_ZERO); + if (!pages) + goto unregister_out;
+ ret = amdgpu_ttm_tt_get_user_pages(bo, pages); if (ret) { pr_err("%s: Failed to get user pages: %d\n", __func__, ret); goto unregister_out; @@ -863,6 +870,12 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) pr_err("%s: Failed to reserve BO\n", __func__); goto release_out; }
+ WARN_ON_ONCE(bo->tbo.ttm->page_flags & TTM_PAGE_FLAG_SWAPPED);
+ memcpy(bo->tbo.ttm->pages, + pages, + sizeof(struct page*) * bo->tbo.ttm->num_pages); amdgpu_bo_placement_from_domain(bo, mem->domain); ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx); if (ret) @@ -872,6 +885,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) release_out: amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm); unregister_out: + kvfree(pages); if (ret) amdgpu_mn_unregister(bo); out:
amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx
[AMD Official Use Only]
I am not sure if we can create a ttm_bo_type_sg bo for userptr. But I have another idea now. we can use flag AMDGPU_AMDKFD_CREATE_USERPTR_BO to create the userptr bo. ________________________________________ 发件人: Kuehling, Felix Felix.Kuehling@amd.com 发送时间: 2021年5月19日 23:11 收件人: Christian König; Pan, Xinhui; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; daniel@ffwll.ch; Koenig, Christian; dri-devel@lists.freedesktop.org 主题: Re: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
Looks like we're creating the userptr BO as ttm_bo_type_device. I guess we should be using ttm_bo_type_sg? BTW, amdgpu_gem_userptr_ioctl also uses ttm_bo_type_device.
Regards, Felix
Am 2021-05-19 um 6:01 a.m. schrieb Christian König:
I'm scratching my head how that is even possible.
See when a BO is created in the system domain it is just an empty hull, e.g. without backing store and allocated pages.
So the swapout function will just ignore it.
Christian.
Am 19.05.21 um 07:07 schrieb Pan, Xinhui:
[AMD Official Use Only]
I have reverted Chris' patch, still hit this failure. Just see two lines in Chris' patch. Any BO in cpu domian would be swapout first. That is why we hit this issue frequently now. But the bug is there long time ago.
for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {list_for_each_entry(bo, &glob->swap_lru[i], swap) {[snip]
for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) {for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
发件人: Pan, Xinhui Xinhui.Pan@amd.com 发送时间: 2021年5月19日 12:09 收件人: Kuehling, Felix; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
yes, we really dont swapout SG BOs. The problems is that before we validate a userptr BO, we create this BO in CPU domain by default. So this BO has chance to swapout.
we set flag TTM_PAGE_FLAG_SG on userptr BO in popluate() which is too late. I have not try to revert Chris' patch as I think it desnt help. Or I can have a try later.
发件人: Kuehling, Felix Felix.Kuehling@amd.com 发送时间: 2021年5月19日 11:29 收件人: Pan, Xinhui; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: Re: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
Swapping SG BOs makes no sense, because TTM doesn't own the pages of this type of BO.
Last I checked, userptr BOs (and other SG BOs) were protected from swapout by the fact that they would not be added to the swap-LRU. But it looks like Christian just removed the swap-LRU. I guess this broke that protection:
commit 2cb51d22d70b18eaf339abf9758bf0b7608da65c Author: Christian König christian.koenig@amd.com Date: Tue Oct 6 16:30:09 2020 +0200
drm/ttm: remove swap LRU v3 Instead evict round robin from each devices SYSTEM and TT domain. v2: reorder num_pages access reported by Dan's script v3: fix rebase fallout, num_pages should be 32bit Signed-off-by: Christian König <christian.koenig@amd.com> Tested-by: Nirmoy Das <nirmoy.das@amd.com> Reviewed-by: Huang Rui <ray.huang@amd.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/424009/Regards, Felix
On 2021-05-18 10:28 p.m., xinhui pan wrote:
cpu 1 cpu 2 kfd alloc BO A(userptr) alloc BO B(GTT) ->init -> validate -> init -> validate -> populate init_user_pages -> swapout BO A //hit ttm pages limit -> get_user_pages (fill up ttm->pages) -> validate -> populate -> swapin BO A // Now hit the BUG
We know that get_user_pages may race with swapout on same BO. Threre are some issues I have met.
- memory corruption.
This is because we do a swap before memory is setup. ttm_tt_swapout() just create a swap_storage with its content being 0x0. So when we setup memory after the swapout. The following swapin makes the memory corrupted.
- panic
When swapout happes with get_user_pages, they touch ttm->pages without anylock. It causes memory corruption too. But I hit page fault mostly.
Signed-off-by: xinhui pan xinhui.pan@amd.com
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 928e8d57cd08..42460e4480f8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -835,6 +835,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) struct amdkfd_process_info *process_info = mem->process_info; struct amdgpu_bo *bo = mem->bo; struct ttm_operation_ctx ctx = { true, false };
struct page **pages; int ret = 0; mutex_lock(&process_info->lock);@@ -852,7 +853,13 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) goto out; }
ret = amdgpu_ttm_tt_get_user_pages(bo, bo->tbo.ttm->pages);
pages = kvmalloc_array(bo->tbo.ttm->num_pages,sizeof(struct page *),GFP_KERNEL | __GFP_ZERO);if (!pages)goto unregister_out;ret = amdgpu_ttm_tt_get_user_pages(bo, pages); if (ret) { pr_err("%s: Failed to get user pages: %d\n",__func__, ret); goto unregister_out; @@ -863,6 +870,12 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) pr_err("%s: Failed to reserve BO\n", __func__); goto release_out; }
WARN_ON_ONCE(bo->tbo.ttm->page_flags & TTM_PAGE_FLAG_SWAPPED);memcpy(bo->tbo.ttm->pages,pages,sizeof(struct page*) * bo->tbo.ttm->num_pages); amdgpu_bo_placement_from_domain(bo, mem->domain); ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx); if (ret)@@ -872,6 +885,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) release_out: amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm); unregister_out:
kvfree(pages); if (ret) amdgpu_mn_unregister(bo);
amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx
The problem is that ttm_bo_type_sg doesn't allocate a page array for the TT object.
Christian.
Am 20.05.21 um 04:58 schrieb Pan, Xinhui:
[AMD Official Use Only]
I am not sure if we can create a ttm_bo_type_sg bo for userptr. But I have another idea now. we can use flag AMDGPU_AMDKFD_CREATE_USERPTR_BO to create the userptr bo. ________________________________________ 发件人: Kuehling, Felix Felix.Kuehling@amd.com 发送时间: 2021年5月19日 23:11 收件人: Christian König; Pan, Xinhui; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; daniel@ffwll.ch; Koenig, Christian; dri-devel@lists.freedesktop.org 主题: Re: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
Looks like we're creating the userptr BO as ttm_bo_type_device. I guess we should be using ttm_bo_type_sg? BTW, amdgpu_gem_userptr_ioctl also uses ttm_bo_type_device.
Regards, Felix
Am 2021-05-19 um 6:01 a.m. schrieb Christian König:
I'm scratching my head how that is even possible.
See when a BO is created in the system domain it is just an empty hull, e.g. without backing store and allocated pages.
So the swapout function will just ignore it.
Christian.
Am 19.05.21 um 07:07 schrieb Pan, Xinhui:
[AMD Official Use Only]
I have reverted Chris' patch, still hit this failure. Just see two lines in Chris' patch. Any BO in cpu domian would be swapout first. That is why we hit this issue frequently now. But the bug is there long time ago.
for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {list_for_each_entry(bo, &glob->swap_lru[i], swap) {[snip]
for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) {for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
发件人: Pan, Xinhui Xinhui.Pan@amd.com 发送时间: 2021年5月19日 12:09 收件人: Kuehling, Felix; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
yes, we really dont swapout SG BOs. The problems is that before we validate a userptr BO, we create this BO in CPU domain by default. So this BO has chance to swapout.
we set flag TTM_PAGE_FLAG_SG on userptr BO in popluate() which is too late. I have not try to revert Chris' patch as I think it desnt help. Or I can have a try later.
发件人: Kuehling, Felix Felix.Kuehling@amd.com 发送时间: 2021年5月19日 11:29 收件人: Pan, Xinhui; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: Re: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
Swapping SG BOs makes no sense, because TTM doesn't own the pages of this type of BO.
Last I checked, userptr BOs (and other SG BOs) were protected from swapout by the fact that they would not be added to the swap-LRU. But it looks like Christian just removed the swap-LRU. I guess this broke that protection:
commit 2cb51d22d70b18eaf339abf9758bf0b7608da65c Author: Christian König christian.koenig@amd.com Date: Tue Oct 6 16:30:09 2020 +0200
drm/ttm: remove swap LRU v3 Instead evict round robin from each devices SYSTEM and TT domain. v2: reorder num_pages access reported by Dan's script v3: fix rebase fallout, num_pages should be 32bit Signed-off-by: Christian König <christian.koenig@amd.com> Tested-by: Nirmoy Das <nirmoy.das@amd.com> Reviewed-by: Huang Rui <ray.huang@amd.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/424009/Regards, Felix
On 2021-05-18 10:28 p.m., xinhui pan wrote:
cpu 1 cpu 2 kfd alloc BO A(userptr) alloc BO B(GTT) ->init -> validate -> init -> validate -> populate init_user_pages -> swapout BO A //hit ttm pages limit -> get_user_pages (fill up ttm->pages) -> validate -> populate -> swapin BO A // Now hit the BUG
We know that get_user_pages may race with swapout on same BO. Threre are some issues I have met.
- memory corruption.
This is because we do a swap before memory is setup. ttm_tt_swapout() just create a swap_storage with its content being 0x0. So when we setup memory after the swapout. The following swapin makes the memory corrupted.
- panic
When swapout happes with get_user_pages, they touch ttm->pages without anylock. It causes memory corruption too. But I hit page fault mostly.
Signed-off-by: xinhui pan xinhui.pan@amd.com
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16+++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 928e8d57cd08..42460e4480f8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -835,6 +835,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) struct amdkfd_process_info *process_info = mem->process_info; struct amdgpu_bo *bo = mem->bo; struct ttm_operation_ctx ctx = { true, false };
struct page **pages; int ret = 0; mutex_lock(&process_info->lock);@@ -852,7 +853,13 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) goto out; }
ret = amdgpu_ttm_tt_get_user_pages(bo, bo->tbo.ttm->pages);
pages = kvmalloc_array(bo->tbo.ttm->num_pages,sizeof(struct page *),GFP_KERNEL | __GFP_ZERO);if (!pages)goto unregister_out;ret = amdgpu_ttm_tt_get_user_pages(bo, pages); if (ret) { pr_err("%s: Failed to get user pages: %d\n",__func__, ret); goto unregister_out; @@ -863,6 +870,12 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) pr_err("%s: Failed to reserve BO\n", __func__); goto release_out; }
WARN_ON_ONCE(bo->tbo.ttm->page_flags & TTM_PAGE_FLAG_SWAPPED);memcpy(bo->tbo.ttm->pages,pages,sizeof(struct page*) * bo->tbo.ttm->num_pages); amdgpu_bo_placement_from_domain(bo, mem->domain); ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx); if (ret)@@ -872,6 +885,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) release_out: amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm); unregister_out:
kvfree(pages); if (ret) amdgpu_mn_unregister(bo);
amd-gfx mailing list amd-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx
[AMD Official Use Only]
swapout function create one swap storage which is filled with zero. And set ttm->page_flags as TTM_PAGE_FLAG_SWAPPED. Just because ttm has no backend page this time, no real data is swapout to this swap storage.
swapin function is called during populate as TTM_PAGE_FLAG_SWAPPED is set. Now here is the problem, we swapin data to ttm bakend memory from swap storage. That just causes the memory been overwritten.
________________________________________ 发件人: Christian König ckoenig.leichtzumerken@gmail.com 发送时间: 2021年5月19日 18:01 收件人: Pan, Xinhui; Kuehling, Felix; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; daniel@ffwll.ch; Koenig, Christian; dri-devel@lists.freedesktop.org 主题: Re: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
I'm scratching my head how that is even possible.
See when a BO is created in the system domain it is just an empty hull, e.g. without backing store and allocated pages.
So the swapout function will just ignore it.
Christian.
Am 19.05.21 um 07:07 schrieb Pan, Xinhui:
[AMD Official Use Only]
I have reverted Chris' patch, still hit this failure. Just see two lines in Chris' patch. Any BO in cpu domian would be swapout first. That is why we hit this issue frequently now. But the bug is there long time ago.
for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {list_for_each_entry(bo, &glob->swap_lru[i], swap) {[snip]
for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) {for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
发件人: Pan, Xinhui Xinhui.Pan@amd.com 发送时间: 2021年5月19日 12:09 收件人: Kuehling, Felix; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
yes, we really dont swapout SG BOs. The problems is that before we validate a userptr BO, we create this BO in CPU domain by default. So this BO has chance to swapout.
we set flag TTM_PAGE_FLAG_SG on userptr BO in popluate() which is too late. I have not try to revert Chris' patch as I think it desnt help. Or I can have a try later.
发件人: Kuehling, Felix Felix.Kuehling@amd.com 发送时间: 2021年5月19日 11:29 收件人: Pan, Xinhui; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: Re: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
Swapping SG BOs makes no sense, because TTM doesn't own the pages of this type of BO.
Last I checked, userptr BOs (and other SG BOs) were protected from swapout by the fact that they would not be added to the swap-LRU. But it looks like Christian just removed the swap-LRU. I guess this broke that protection:
commit 2cb51d22d70b18eaf339abf9758bf0b7608da65c Author: Christian König christian.koenig@amd.com Date: Tue Oct 6 16:30:09 2020 +0200
drm/ttm: remove swap LRU v3 Instead evict round robin from each devices SYSTEM and TT domain. v2: reorder num_pages access reported by Dan's script v3: fix rebase fallout, num_pages should be 32bit Signed-off-by: Christian König <christian.koenig@amd.com> Tested-by: Nirmoy Das <nirmoy.das@amd.com> Reviewed-by: Huang Rui <ray.huang@amd.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.freedesktop.org%2Fpatch%2F424009%2F&data=04%7C01%7CXinhui.Pan%40amd.com%7Cb4422d8b3e4947cd243c08d91aad14c3%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637570152942496679%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=K3%2FnFpN56y8L49UuYRM6SqefVFLnqIwpDAtWpS1XvnQ%3D&reserved=0Regards, Felix
On 2021-05-18 10:28 p.m., xinhui pan wrote:
cpu 1 cpu 2 kfd alloc BO A(userptr) alloc BO B(GTT) ->init -> validate -> init -> validate -> populate init_user_pages -> swapout BO A //hit ttm pages limit -> get_user_pages (fill up ttm->pages) -> validate -> populate -> swapin BO A // Now hit the BUG
We know that get_user_pages may race with swapout on same BO. Threre are some issues I have met.
- memory corruption.
This is because we do a swap before memory is setup. ttm_tt_swapout() just create a swap_storage with its content being 0x0. So when we setup memory after the swapout. The following swapin makes the memory corrupted.
- panic
When swapout happes with get_user_pages, they touch ttm->pages without anylock. It causes memory corruption too. But I hit page fault mostly.
Signed-off-by: xinhui pan xinhui.pan@amd.com
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 928e8d57cd08..42460e4480f8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -835,6 +835,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) struct amdkfd_process_info *process_info = mem->process_info; struct amdgpu_bo *bo = mem->bo; struct ttm_operation_ctx ctx = { true, false };
struct page **pages; int ret = 0; mutex_lock(&process_info->lock);@@ -852,7 +853,13 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) goto out; }
ret = amdgpu_ttm_tt_get_user_pages(bo, bo->tbo.ttm->pages);
pages = kvmalloc_array(bo->tbo.ttm->num_pages,sizeof(struct page *),GFP_KERNEL | __GFP_ZERO);if (!pages)goto unregister_out;ret = amdgpu_ttm_tt_get_user_pages(bo, pages); if (ret) { pr_err("%s: Failed to get user pages: %d\n", __func__, ret); goto unregister_out;@@ -863,6 +870,12 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) pr_err("%s: Failed to reserve BO\n", __func__); goto release_out; }
WARN_ON_ONCE(bo->tbo.ttm->page_flags & TTM_PAGE_FLAG_SWAPPED);memcpy(bo->tbo.ttm->pages,pages,sizeof(struct page*) * bo->tbo.ttm->num_pages); amdgpu_bo_placement_from_domain(bo, mem->domain); ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx); if (ret)@@ -872,6 +885,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) release_out: amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm); unregister_out:
kvfree(pages); if (ret) amdgpu_mn_unregister(bo);
amd-gfx mailing list amd-gfx@lists.freedesktop.org https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.free...
swapout function create one swap storage which is filled with zero. And set ttm->page_flags as TTM_PAGE_FLAG_SWAPPED. Just because ttm has no backend page this time, no real data is swapout to this swap storage.
That's the fundamental problem. A TT object which isn't populated shouldn't be considered for swapout nor eviction in the first place.
I'm going to take a look later today.
Christian.
Am 20.05.21 um 04:55 schrieb Pan, Xinhui:
[AMD Official Use Only]
swapout function create one swap storage which is filled with zero. And set ttm->page_flags as TTM_PAGE_FLAG_SWAPPED. Just because ttm has no backend page this time, no real data is swapout to this swap storage.
swapin function is called during populate as TTM_PAGE_FLAG_SWAPPED is set. Now here is the problem, we swapin data to ttm bakend memory from swap storage. That just causes the memory been overwritten.
发件人: Christian König ckoenig.leichtzumerken@gmail.com 发送时间: 2021年5月19日 18:01 收件人: Pan, Xinhui; Kuehling, Felix; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; daniel@ffwll.ch; Koenig, Christian; dri-devel@lists.freedesktop.org 主题: Re: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
I'm scratching my head how that is even possible.
See when a BO is created in the system domain it is just an empty hull, e.g. without backing store and allocated pages.
So the swapout function will just ignore it.
Christian.
Am 19.05.21 um 07:07 schrieb Pan, Xinhui:
[AMD Official Use Only]
I have reverted Chris' patch, still hit this failure. Just see two lines in Chris' patch. Any BO in cpu domian would be swapout first. That is why we hit this issue frequently now. But the bug is there long time ago.
for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {list_for_each_entry(bo, &glob->swap_lru[i], swap) {[snip]
for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) {for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
发件人: Pan, Xinhui Xinhui.Pan@amd.com 发送时间: 2021年5月19日 12:09 收件人: Kuehling, Felix; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
yes, we really dont swapout SG BOs. The problems is that before we validate a userptr BO, we create this BO in CPU domain by default. So this BO has chance to swapout.
we set flag TTM_PAGE_FLAG_SG on userptr BO in popluate() which is too late. I have not try to revert Chris' patch as I think it desnt help. Or I can have a try later.
发件人: Kuehling, Felix Felix.Kuehling@amd.com 发送时间: 2021年5月19日 11:29 收件人: Pan, Xinhui; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: Re: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
Swapping SG BOs makes no sense, because TTM doesn't own the pages of this type of BO.
Last I checked, userptr BOs (and other SG BOs) were protected from swapout by the fact that they would not be added to the swap-LRU. But it looks like Christian just removed the swap-LRU. I guess this broke that protection:
commit 2cb51d22d70b18eaf339abf9758bf0b7608da65c Author: Christian König christian.koenig@amd.com Date: Tue Oct 6 16:30:09 2020 +0200
drm/ttm: remove swap LRU v3 Instead evict round robin from each devices SYSTEM and TT domain. v2: reorder num_pages access reported by Dan's script v3: fix rebase fallout, num_pages should be 32bit Signed-off-by: Christian König <christian.koenig@amd.com> Tested-by: Nirmoy Das <nirmoy.das@amd.com> Reviewed-by: Huang Rui <ray.huang@amd.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.freedesktop.org%2Fpatch%2F424009%2F&data=04%7C01%7CXinhui.Pan%40amd.com%7Cb4422d8b3e4947cd243c08d91aad14c3%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637570152942496679%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=K3%2FnFpN56y8L49UuYRM6SqefVFLnqIwpDAtWpS1XvnQ%3D&reserved=0Regards, Felix
On 2021-05-18 10:28 p.m., xinhui pan wrote:
cpu 1 cpu 2 kfd alloc BO A(userptr) alloc BO B(GTT) ->init -> validate -> init -> validate -> populate init_user_pages -> swapout BO A //hit ttm pages limit -> get_user_pages (fill up ttm->pages) -> validate -> populate -> swapin BO A // Now hit the BUG
We know that get_user_pages may race with swapout on same BO. Threre are some issues I have met.
- memory corruption.
This is because we do a swap before memory is setup. ttm_tt_swapout() just create a swap_storage with its content being 0x0. So when we setup memory after the swapout. The following swapin makes the memory corrupted.
- panic
When swapout happes with get_user_pages, they touch ttm->pages without anylock. It causes memory corruption too. But I hit page fault mostly.
Signed-off-by: xinhui pan xinhui.pan@amd.com
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 928e8d57cd08..42460e4480f8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -835,6 +835,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) struct amdkfd_process_info *process_info = mem->process_info; struct amdgpu_bo *bo = mem->bo; struct ttm_operation_ctx ctx = { true, false };
struct page **pages; int ret = 0; mutex_lock(&process_info->lock);@@ -852,7 +853,13 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) goto out; }
ret = amdgpu_ttm_tt_get_user_pages(bo, bo->tbo.ttm->pages);
pages = kvmalloc_array(bo->tbo.ttm->num_pages,sizeof(struct page *),GFP_KERNEL | __GFP_ZERO);if (!pages)goto unregister_out;ret = amdgpu_ttm_tt_get_user_pages(bo, pages); if (ret) { pr_err("%s: Failed to get user pages: %d\n", __func__, ret); goto unregister_out;@@ -863,6 +870,12 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) pr_err("%s: Failed to reserve BO\n", __func__); goto release_out; }
WARN_ON_ONCE(bo->tbo.ttm->page_flags & TTM_PAGE_FLAG_SWAPPED);memcpy(bo->tbo.ttm->pages,pages,sizeof(struct page*) * bo->tbo.ttm->num_pages); amdgpu_bo_placement_from_domain(bo, mem->domain); ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx); if (ret)@@ -872,6 +885,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) release_out: amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm); unregister_out:
kvfree(pages); if (ret) amdgpu_mn_unregister(bo);
amd-gfx mailing list amd-gfx@lists.freedesktop.org https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.free...
I just sent out patch below yesterday. swapping unpopulated bo is useless indeed.
[RFC PATCH 2/2] drm/ttm: skip swapout when ttm has no backend page.
[AMD Official Use Only]
I just sent out patch below yesterday. swapping unpopulated bo is useless indeed.
[RFC PATCH 2/2] drm/ttm: skip swapout when ttm has no backend page.
________________________________________ 发件人: Christian König ckoenig.leichtzumerken@gmail.com 发送时间: 2021年5月20日 14:39 收件人: Pan, Xinhui; Kuehling, Felix; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; daniel@ffwll.ch; Koenig, Christian; dri-devel@lists.freedesktop.org 主题: Re: 回复: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
swapout function create one swap storage which is filled with zero. And set ttm->page_flags as TTM_PAGE_FLAG_SWAPPED. Just because ttm has no backend page this time, no real data is swapout to this swap storage.
That's the fundamental problem. A TT object which isn't populated shouldn't be considered for swapout nor eviction in the first place.
I'm going to take a look later today.
Christian.
Am 20.05.21 um 04:55 schrieb Pan, Xinhui:
[AMD Official Use Only]
swapout function create one swap storage which is filled with zero. And set ttm->page_flags as TTM_PAGE_FLAG_SWAPPED. Just because ttm has no backend page this time, no real data is swapout to this swap storage.
swapin function is called during populate as TTM_PAGE_FLAG_SWAPPED is set. Now here is the problem, we swapin data to ttm bakend memory from swap storage. That just causes the memory been overwritten.
发件人: Christian König ckoenig.leichtzumerken@gmail.com 发送时间: 2021年5月19日 18:01 收件人: Pan, Xinhui; Kuehling, Felix; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; daniel@ffwll.ch; Koenig, Christian; dri-devel@lists.freedesktop.org 主题: Re: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
I'm scratching my head how that is even possible.
See when a BO is created in the system domain it is just an empty hull, e.g. without backing store and allocated pages.
So the swapout function will just ignore it.
Christian.
Am 19.05.21 um 07:07 schrieb Pan, Xinhui:
[AMD Official Use Only]
I have reverted Chris' patch, still hit this failure. Just see two lines in Chris' patch. Any BO in cpu domian would be swapout first. That is why we hit this issue frequently now. But the bug is there long time ago.
for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {list_for_each_entry(bo, &glob->swap_lru[i], swap) {[snip]
for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) {for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
发件人: Pan, Xinhui Xinhui.Pan@amd.com 发送时间: 2021年5月19日 12:09 收件人: Kuehling, Felix; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: 回复: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
yes, we really dont swapout SG BOs. The problems is that before we validate a userptr BO, we create this BO in CPU domain by default. So this BO has chance to swapout.
we set flag TTM_PAGE_FLAG_SG on userptr BO in popluate() which is too late. I have not try to revert Chris' patch as I think it desnt help. Or I can have a try later.
发件人: Kuehling, Felix Felix.Kuehling@amd.com 发送时间: 2021年5月19日 11:29 收件人: Pan, Xinhui; amd-gfx@lists.freedesktop.org 抄送: Deucher, Alexander; Koenig, Christian; dri-devel@lists.freedesktop.org; daniel@ffwll.ch 主题: Re: [RFC PATCH 1/2] drm/amdgpu: Fix memory corruption due to swapout and swapin
Swapping SG BOs makes no sense, because TTM doesn't own the pages of this type of BO.
Last I checked, userptr BOs (and other SG BOs) were protected from swapout by the fact that they would not be added to the swap-LRU. But it looks like Christian just removed the swap-LRU. I guess this broke that protection:
commit 2cb51d22d70b18eaf339abf9758bf0b7608da65c Author: Christian König christian.koenig@amd.com Date: Tue Oct 6 16:30:09 2020 +0200
drm/ttm: remove swap LRU v3 Instead evict round robin from each devices SYSTEM and TT domain. v2: reorder num_pages access reported by Dan's script v3: fix rebase fallout, num_pages should be 32bit Signed-off-by: Christian König <christian.koenig@amd.com> Tested-by: Nirmoy Das <nirmoy.das@amd.com> Reviewed-by: Huang Rui <ray.huang@amd.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.freedesktop.org%2Fpatch%2F424009%2F&data=04%7C01%7CXinhui.Pan%40amd.com%7C2f5f749422eb44efa95408d91b5a029c%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637570895679516712%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=I9K%2FsTdCESLlS9P5rLOGUqEGCcxi0Jc7aaEOltyBP4M%3D&reserved=0Regards, Felix
On 2021-05-18 10:28 p.m., xinhui pan wrote:
cpu 1 cpu 2 kfd alloc BO A(userptr) alloc BO B(GTT) ->init -> validate -> init -> validate -> populate init_user_pages -> swapout BO A //hit ttm pages limit -> get_user_pages (fill up ttm->pages) -> validate -> populate -> swapin BO A // Now hit the BUG
We know that get_user_pages may race with swapout on same BO. Threre are some issues I have met.
- memory corruption.
This is because we do a swap before memory is setup. ttm_tt_swapout() just create a swap_storage with its content being 0x0. So when we setup memory after the swapout. The following swapin makes the memory corrupted.
- panic
When swapout happes with get_user_pages, they touch ttm->pages without anylock. It causes memory corruption too. But I hit page fault mostly.
Signed-off-by: xinhui pan xinhui.pan@amd.com
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index 928e8d57cd08..42460e4480f8 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -835,6 +835,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) struct amdkfd_process_info *process_info = mem->process_info; struct amdgpu_bo *bo = mem->bo; struct ttm_operation_ctx ctx = { true, false };
struct page **pages; int ret = 0; mutex_lock(&process_info->lock);@@ -852,7 +853,13 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) goto out; }
ret = amdgpu_ttm_tt_get_user_pages(bo, bo->tbo.ttm->pages);
pages = kvmalloc_array(bo->tbo.ttm->num_pages,sizeof(struct page *),GFP_KERNEL | __GFP_ZERO);if (!pages)goto unregister_out;ret = amdgpu_ttm_tt_get_user_pages(bo, pages); if (ret) { pr_err("%s: Failed to get user pages: %d\n", __func__, ret); goto unregister_out;@@ -863,6 +870,12 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) pr_err("%s: Failed to reserve BO\n", __func__); goto release_out; }
WARN_ON_ONCE(bo->tbo.ttm->page_flags & TTM_PAGE_FLAG_SWAPPED);memcpy(bo->tbo.ttm->pages,pages,sizeof(struct page*) * bo->tbo.ttm->num_pages); amdgpu_bo_placement_from_domain(bo, mem->domain); ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx); if (ret)@@ -872,6 +885,7 @@ static int init_user_pages(struct kgd_mem *mem, uint64_t user_addr) release_out: amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm); unregister_out:
kvfree(pages); if (ret) amdgpu_mn_unregister(bo);
amd-gfx mailing list amd-gfx@lists.freedesktop.org https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.free...
dri-devel@lists.freedesktop.org
-
Christian König -
Felix Kuehling -
Pan, Xinhui -
xinhui pan