The change you shared with me fixes the crash. Pl include in v8. On 3/18/2024 10:06 AM, Sharma, Shashank wrote: > > [AMD Official Use Only - General] > > > Already sent a NULL check patch based on this backtrace, I am waiting > for Rajneesh's feedback. > > Regards > Shashank > ------------------------------------------------------------------------ > *From:* Bhardwaj, Rajneesh > *Sent:* Monday, March 18, 2024 3:04 PM > *To:* Sharma, Shashank ; > amd-gfx@lists.freedesktop.org > *Cc:* Koenig, Christian ; Deucher, Alexander > ; Kuehling, Felix > *Subject:* Re: [PATCH v7 2/2] drm/amdgpu: sync page table freeing with > tlb flush > > HI 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 for SHM_HUGETLB is obsolete 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]  > [  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 > Cc: > Alex Deucher > Cc: Felix Kuehling > Cc: > Rajneesh Bhardwaj > Acked-by: Felix Kuehling > Acked-by: > Rajneesh Bhardwaj > Tested-by: Rajneesh Bhardwaj > > Signed-off-by: Shashank Sharma > --- > 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); } >