[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@xxxxxxx>
发送时间: 2021年5月19日 10:28
收件人: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
抄送: Kuehling, Felix; Deucher, Alexander; Koenig, Christian; dri-devel@xxxxxxxxxxxxxxxxxxxxx; daniel@xxxxxxxx; 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@xxxxxxx>
---
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
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