The change you shared with me fixes the crash. Pl include in v8.
[AMD Official Use Only - General]
Already sent a NULL check patch based on this backtrace, I am waiting for Rajneesh's feedback.
RegardsShashank
From: Bhardwaj, Rajneesh <Rajneesh.Bhardwaj@xxxxxxx>
Sent: Monday, March 18, 2024 3:04 PM
To: Sharma, Shashank <Shashank.Sharma@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx <amd-gfx@xxxxxxxxxxxxxxxxxxxxx>
Cc: Koenig, Christian <Christian.Koenig@xxxxxxx>; Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Kuehling, Felix <Felix.Kuehling@xxxxxxx>
Subject: Re: [PATCH v7 2/2] drm/amdgpu: sync page table freeing with tlb flushHI Shashank
We'll probably need a v8 with the null pointer crash fixed i.e. before freeing the PT entries check for a valid entry before calling amdgpu_vm_pt_free. The crash is seen with device memory allocators but the system memory allocators are looking fine.
[ 127.255863] [drm] Using MTYPE_RW for local memory
[ 333.606136] hugetlbfs: test_with_MPI.e (25268): Using mlock ulimits for SHM_HUGETLB is obsolete
[ 415.351447] BUG: kernel NULL pointer dereference, address: 0000000000000008
[ 415.359245] #PF: supervisor write access in kernel mode
[ 415.365081] #PF: error_code(0x0002) - not-present page
[ 415.370817] PGD 101259067 P4D 101259067 PUD 10125a067 PMD 0
[ 415.377140] Oops: 0002 [#1] PREEMPT SMP NOPTI
[ 415.382004] CPU: 0 PID: 25481 Comm: test_with_MPI.e Tainted: G OE 5.18.2-mi300-build-140423-ubuntu-22.04+ #24
[ 415.394437] Hardware name: AMD Corporation Sh51p/Sh51p, BIOS RMO1001AS 02/21/2024
[ 415.402797] RIP: 0010:amdgpu_vm_ptes_update+0x6fd/0xa10 [amdgpu]
[ 415.409648] Code: 4c 89 ff 4d 8d 66 30 e8 f1 ed ff ff 48 85 db 74 42 48 39 5d a0 74 40 48 8b 53 20 48 8b 4b 18 48 8d 43 18 48 8d 75 b0 4c 89 ff <48
> 89 51 08 48 89 0a 49 8b 56 30 48 89 42 08 48 89 53 18 4c 89 63
[ 415.430621] RSP: 0018:ffffc9000401f990 EFLAGS: 00010287
[ 415.436456] RAX: ffff888147bb82f0 RBX: ffff888147bb82d8 RCX: 0000000000000000
[ 415.444426] RDX: 0000000000000000 RSI: ffffc9000401fa30 RDI: ffff888161f80000
[ 415.452397] RBP: ffffc9000401fa80 R08: 0000000000000000 R09: ffffc9000401fa00
[ 415.460368] R10: 00000007f0cc0000 R11: 00000007f0c85000 R12: ffffc9000401fb20
[ 415.468340] R13: 00000007f0d00000 R14: ffffc9000401faf0 R15: ffff888161f80000
[ 415.476312] FS: 00007f132ff89840(0000) GS:ffff889f87c00000(0000) knlGS:0000000000000000
[ 415.485350] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 415.491767] CR2: 0000000000000008 CR3: 0000000161d46003 CR4: 0000000000770ef0
[ 415.499738] PKRU: 55555554
[ 415.502750] Call Trace:
[ 415.505482] <TASK>
[ 415.507825] amdgpu_vm_update_range+0x32a/0x880 [amdgpu]
[ 415.513869] amdgpu_vm_clear_freed+0x117/0x250 [amdgpu]
[ 415.519814] amdgpu_amdkfd_gpuvm_unmap_memory_from_gpu+0x18c/0x250 [amdgpu]
[ 415.527729] kfd_ioctl_unmap_memory_from_gpu+0xed/0x340 [amdgpu]
[ 415.534551] kfd_ioctl+0x3b6/0x510 [amdgpu]
[ 415.539324] ? kfd_ioctl_get_dmabuf_info+0x1d0/0x1d0 [amdgpu]
[ 415.545844] ? __fget_light+0xc5/0x100
[ 415.550037] __x64_sys_ioctl+0x91/0xc0
[ 415.554227] do_syscall_64+0x5c/0x80
[ 415.558223] ? debug_smp_processor_id+0x17/0x20
[ 415.563285] ? fpregs_assert_state_consistent+0x23/0x60
[ 415.569124] ? exit_to_user_mode_prepare+0x45/0x190
[ 415.574572] ? ksys_write+0xce/0xe0
On 3/18/2024 8:08 AM, Shashank Sharma wrote:
The idea behind this patch is to delay the freeing of PT entry objects until the TLB flush is done. This patch: - Adds a tlb_flush_waitlist in amdgpu_vm_update_params which will keep the objects that need to be freed after tlb_flush. - Adds PT entries in this list in amdgpu_vm_ptes_update after finding the PT entry. - Changes functionality of amdgpu_vm_pt_free_dfs from (df_search + free) to simply freeing of the BOs, also renames it to amdgpu_vm_pt_free_list to reflect this same. - Exports function amdgpu_vm_pt_free_list to be called directly. - Calls amdgpu_vm_pt_free_list directly from amdgpu_vm_update_range. V2: rebase V4: Addressed review comments from Christian - add only locked PTEs entries in TLB flush waitlist. - do not create a separate function for list flush. - do not create a new lock for TLB flush. - there is no need to wait on tlb_flush_fence exclusively. V5: Addressed review comments from Christian - change the amdgpu_vm_pt_free_dfs's functionality to simple freeing of the objects and rename it. - add all the PTE objects in params->tlb_flush_waitlist - let amdgpu_vm_pt_free_root handle the freeing of BOs independently - call amdgpu_vm_pt_free_list directly V6: Rebase V7: Rebase Cc: Christian König <Christian.Koenig@xxxxxxx> Cc: Alex Deucher <alexander.deucher@xxxxxxx> Cc: Felix Kuehling <felix.kuehling@xxxxxxx> Cc: Rajneesh Bhardwaj <rajneesh.bhardwaj@xxxxxxx> Acked-by: Felix Kuehling <felix.kuehling@xxxxxxx> Acked-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@xxxxxxx> Tested-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@xxxxxxx> Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxx> --- drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 5 ++- drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 7 +++ drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c | 53 +++++++++++++---------- 3 files changed, 40 insertions(+), 25 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c index 26f1c3359642..eaa402f99fe0 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c @@ -977,6 +977,7 @@ int amdgpu_vm_update_range(struct amdgpu_device *adev, struct amdgpu_vm *vm, params.unlocked = unlocked; params.needs_flush = flush_tlb; params.allow_override = allow_override; + INIT_LIST_HEAD(¶ms.tlb_flush_waitlist); /* Implicitly sync to command submissions in the same VM before * unmapping. Sync to moving fences before mapping. @@ -1062,8 +1063,10 @@ int amdgpu_vm_update_range(struct amdgpu_device *adev, struct amdgpu_vm *vm, if (r) goto error_unlock; - if (params.needs_flush) + if (params.needs_flush) { r = amdgpu_vm_tlb_flush(¶ms, fence); + amdgpu_vm_pt_free_list(adev, ¶ms); + } error_unlock: amdgpu_vm_eviction_unlock(vm); diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h index b0a4fe683352..54d7da396de0 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h @@ -266,6 +266,11 @@ struct amdgpu_vm_update_params { * to be overridden for NUMA local memory. */ bool allow_override; + + /** + * @tlb_flush_waitlist: temporary storage for BOs until tlb_flush + */ + struct list_head tlb_flush_waitlist; }; struct amdgpu_vm_update_funcs { @@ -547,6 +552,8 @@ int amdgpu_vm_ptes_update(struct amdgpu_vm_update_params *params, uint64_t start, uint64_t end, uint64_t dst, uint64_t flags); void amdgpu_vm_pt_free_work(struct work_struct *work); +void amdgpu_vm_pt_free_list(struct amdgpu_device *adev, + struct amdgpu_vm_update_params *params); #if defined(CONFIG_DEBUG_FS) void amdgpu_debugfs_vm_bo_info(struct amdgpu_vm *vm, struct seq_file *m); diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c index 601df0ce8290..440dc8c581fc 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c @@ -622,40 +622,30 @@ void amdgpu_vm_pt_free_work(struct work_struct *work) } /** - * amdgpu_vm_pt_free_dfs - free PD/PT levels + * amdgpu_vm_pt_free_list - free PD/PT levels * * @adev: amdgpu device structure - * @vm: amdgpu vm structure - * @start: optional cursor where to start freeing PDs/PTs - * @unlocked: vm resv unlock status + * @params: see amdgpu_vm_update_params definition * - * Free the page directory or page table level and all sub levels. + * Free the page directory objects saved in the flush list */ -static void amdgpu_vm_pt_free_dfs(struct amdgpu_device *adev, - struct amdgpu_vm *vm, - struct amdgpu_vm_pt_cursor *start, - bool unlocked) +void amdgpu_vm_pt_free_list(struct amdgpu_device *adev, + struct amdgpu_vm_update_params *params) { - struct amdgpu_vm_pt_cursor cursor; - struct amdgpu_vm_bo_base *entry; + struct amdgpu_vm_bo_base *entry, *next; + struct amdgpu_vm *vm = params->vm; + bool unlocked = params->unlocked; if (unlocked) { spin_lock(&vm->status_lock); - for_each_amdgpu_vm_pt_dfs_safe(adev, vm, start, cursor, entry) - list_move(&entry->vm_status, &vm->pt_freed); - - if (start) - list_move(&start->entry->vm_status, &vm->pt_freed); + list_splice_init(&vm->pt_freed, ¶ms->tlb_flush_waitlist); spin_unlock(&vm->status_lock); schedule_work(&vm->pt_free_work); return; } - for_each_amdgpu_vm_pt_dfs_safe(adev, vm, start, cursor, entry) + list_for_each_entry_safe(entry, next, ¶ms->tlb_flush_waitlist, vm_status) amdgpu_vm_pt_free(entry); - - if (start) - amdgpu_vm_pt_free(start->entry); } /** @@ -667,7 +657,11 @@ static void amdgpu_vm_pt_free_dfs(struct amdgpu_device *adev, */ void amdgpu_vm_pt_free_root(struct amdgpu_device *adev, struct amdgpu_vm *vm) { - amdgpu_vm_pt_free_dfs(adev, vm, NULL, false); + struct amdgpu_vm_pt_cursor cursor; + struct amdgpu_vm_bo_base *entry; + + for_each_amdgpu_vm_pt_dfs_safe(adev, vm, NULL, cursor, entry) + amdgpu_vm_pt_free(entry); } /** @@ -972,10 +966,21 @@ int amdgpu_vm_ptes_update(struct amdgpu_vm_update_params *params, while (cursor.pfn < frag_start) { /* Make sure previous mapping is freed */ if (cursor.entry->bo) { + struct amdgpu_vm_pt_cursor seek; + struct amdgpu_vm_bo_base *entry; + params->needs_flush = true; - amdgpu_vm_pt_free_dfs(adev, params->vm, - &cursor, - params->unlocked); + spin_lock(¶ms->vm->status_lock); + for_each_amdgpu_vm_pt_dfs_safe(adev, params->vm, &cursor, + seek, entry) { + list_move(&entry->vm_status, + ¶ms->tlb_flush_waitlist); + } + + /* enter start node now */ + list_move(&cursor.entry->vm_status, + ¶ms->tlb_flush_waitlist); + spin_unlock(¶ms->vm->status_lock); } amdgpu_vm_pt_next(adev, &cursor); }
