kernel/linux.git/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c, branch v6.19.12

drm/amdgpu: caller should make sure not to double free

2025-11-04T16:33:53+00:00

Remove the NULL check from amdgpu_hmm_range_free for hmm_pfns as caller is responsible not to call amdgpu_hmm_range_free more than once. Signed-off-by: Sunil Khatri Reviewed-by: Christian König Reviewed-by: Felix Kuehling Signed-off-by: Alex Deucher

drm/amdkfd: Fix use-after-free of HMM range in svm_range_validate_and_map()

2025-10-28T14:02:21+00:00

The function svm_range_validate_and_map() was freeing `range` when amdgpu_hmm_range_get_pages() failed. But later, the code still used the same `range` pointer and freed it again. This could cause a use-after-free and double-free issue. The fix sets `range = NULL` right after it is freed and checks for `range` before using or freeing it again. v2: Removed duplicate !r check in the condition for clarity. v3: In amdgpu_hmm_range_get_pages(), when hmm_range_fault() fails, we kvfree(pfns) but leave the pointer in hmm_range->hmm_pfns still pointing to freed memory. The caller (or amdgpu_hmm_range_free(range)) may try to free range->hmm_range.hmm_pfns again, causing a double free, Setting hmm_range->hmm_pfns = NULL immediately after kvfree(pfns) prevents both double free. (Philip) In svm_range_validate_and_map(), When r == 0, it means success → range is not NULL. When r != 0, it means failure → already made range = NULL. So checking both (!r && range) is unnecessary because the moment r == 0, we automatically know range exists and is safe to use. (Philip) Fixes: 737da5363cc0 ("drm/amdgpu: update the functions to use amdgpu version of hmm") Reported by: Dan Carpenter Cc: Philip Yang Cc: Sunil Khatri Cc: Christian König Cc: Alex Deucher Signed-off-by: Srinivasan Shanmugam Reviewed-by: Philip Yang Signed-off-by: Alex Deucher

drm/amdgpu: null check for hmm_pfns ptr before freeing it

2025-10-28T13:54:46+00:00

Due to low memory or when num of pages is too big to be accomodated, allocation could fail for pfn's. Chekc hmm_pfns for NULL before calling the kvfree for the it. Signed-off-by: Sunil Khatri Acked-by: Arunpravin Paneer Selvam Signed-off-by: Alex Deucher

drm/amdgpu: add the kernel docs for alloc/free/valid range

2025-10-20T22:25:46+00:00

Add kernel docs for the functions related to hmm_range. Documents added for functions: amdgpu_hmm_range_valid amdgpu_hmm_range_alloc amdgpu_hmm_range_free Signed-off-by: Sunil Khatri Reviewed-by: Christian König Signed-off-by: Alex Deucher

drm/amdgpu: update the functions to use amdgpu version of hmm

2025-10-13T18:14:36+00:00

At times we need a bo reference for hmm and for that add a new struct amdgpu_hmm_range which will hold an optional bo member and hmm_range. Use amdgpu_hmm_range instead of hmm_range and let the bo as an optional argument for the caller if they want to the bo reference to be taken or they want to handle that explicitly. Signed-off-by: Sunil Khatri Reviewed-by: Christian König Signed-off-by: Alex Deucher

drm/amdgpu: clean up amdgpu hmm range functions

2025-10-13T18:14:28+00:00

Clean up the amdgpu hmm range functions for clearer definition of each. a. Split amdgpu_ttm_tt_get_user_pages_done into two: 1. amdgpu_hmm_range_valid: To check if the user pages are valid and update seq num 2. amdgpu_hmm_range_free: Clean up the hmm range and pfn memory. b. amdgpu_ttm_tt_get_user_pages_done and amdgpu_ttm_tt_discard_user_pages are similar function so remove discard and directly use amdgpu_hmm_range_free to clean up the hmm range and pfn memory. Suggested-by: Christian König Signed-off-by: Sunil Khatri Reviewed-by: Christian König Signed-off-by: Alex Deucher

drm/amdgpu: use user provided hmm_range buffer in amdgpu_ttm_tt_get_user_pages

2025-10-13T18:14:28+00:00

update the amdgpu_ttm_tt_get_user_pages and all dependent function along with it callers to use a user allocated hmm_range buffer instead hmm layer allocates the buffer. This is a need to get hmm_range pointers easily accessible without accessing the bo and that is a requirement for the userqueue to lock the userptrs effectively. Signed-off-by: Sunil Khatri Reviewed-by: Christian König Signed-off-by: Alex Deucher

drm/amdgpu: use hmm_pfns instead of array of pages

2025-09-23T14:22:31+00:00

we dont need to allocate local array of pages to hold the pages returned by the hmm, instead we could use the hmm_range structure itself to get to hmm_pfn and get the required pages directly. This avoids call to alloc/free quite a lot. Signed-off-by: Sunil Khatri Suggested-by: Christian König Reviewed-by: Christian König Acked-by: Felix Kuehling Signed-off-by: Alex Deucher

drm/amdkfd: Remove arbitrary timeout for hmm_range_fault

2024-05-13T19:44:02+00:00

On system with khugepaged enabled and user cases with THP buffer, the hmm_range_fault may takes > 15 seconds to return -EBUSY, the arbitrary timeout value is not accurate, cause memory allocation failure. Remove the arbitrary timeout value, return EAGAIN to application if hmm_range_fault return EBUSY, then userspace libdrm and Thunk will call ioctl again. Change EAGAIN to debug message as this is not error. Signed-off-by: Philip Yang Reviewed-by: Felix Kuehling Signed-off-by: Alex Deucher

drm/amdgpu: fix use-after-free bug

2024-03-20T17:12:56+00:00

The bug can be triggered by sending a single amdgpu_gem_userptr_ioctl to the AMDGPU DRM driver on any ASICs with an invalid address and size. The bug was reported by Joonkyo Jung . For example the following code: static void Syzkaller1(int fd) { struct drm_amdgpu_gem_userptr arg; int ret; arg.addr = 0xffffffffffff0000; arg.size = 0x80000000; /*2 Gb*/ arg.flags = 0x7; ret = drmIoctl(fd, 0xc1186451/*amdgpu_gem_userptr_ioctl*/, &arg); } Due to the address and size are not valid there is a failure in amdgpu_hmm_register->mmu_interval_notifier_insert->__mmu_interval_notifier_insert-> check_shl_overflow, but we even the amdgpu_hmm_register failure we still call amdgpu_hmm_unregister into amdgpu_gem_object_free which causes access to a bad address. The following stack is below when the issue is reproduced when Kazan is enabled: [ +0.000014] Hardware name: ASUS System Product Name/ROG STRIX B550-F GAMING (WI-FI), BIOS 1401 12/03/2020 [ +0.000009] RIP: 0010:mmu_interval_notifier_remove+0x327/0x340 [ +0.000017] Code: ff ff 49 89 44 24 08 48 b8 00 01 00 00 00 00 ad de 4c 89 f7 49 89 47 40 48 83 c0 22 49 89 47 48 e8 ce d1 2d 01 e9 32 ff ff ff <0f> 0b e9 16 ff ff ff 4c 89 ef e8 fa 14 b3 ff e9 36 ff ff ff e8 80 [ +0.000014] RSP: 0018:ffffc90002657988 EFLAGS: 00010246 [ +0.000013] RAX: 0000000000000000 RBX: 1ffff920004caf35 RCX: ffffffff8160565b [ +0.000011] RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffff8881a9f78260 [ +0.000010] RBP: ffffc90002657a70 R08: 0000000000000001 R09: fffff520004caf25 [ +0.000010] R10: 0000000000000003 R11: ffffffff8161d1d6 R12: ffff88810e988c00 [ +0.000010] R13: ffff888126fb5a00 R14: ffff88810e988c0c R15: ffff8881a9f78260 [ +0.000011] FS: 00007ff9ec848540(0000) GS:ffff8883cc880000(0000) knlGS:0000000000000000 [ +0.000012] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ +0.000010] CR2: 000055b3f7e14328 CR3: 00000001b5770000 CR4: 0000000000350ef0 [ +0.000010] Call Trace: [ +0.000006] [ +0.000007] ? show_regs+0x6a/0x80 [ +0.000018] ? __warn+0xa5/0x1b0 [ +0.000019] ? mmu_interval_notifier_remove+0x327/0x340 [ +0.000018] ? report_bug+0x24a/0x290 [ +0.000022] ? handle_bug+0x46/0x90 [ +0.000015] ? exc_invalid_op+0x19/0x50 [ +0.000016] ? asm_exc_invalid_op+0x1b/0x20 [ +0.000017] ? kasan_save_stack+0x26/0x50 [ +0.000017] ? mmu_interval_notifier_remove+0x23b/0x340 [ +0.000019] ? mmu_interval_notifier_remove+0x327/0x340 [ +0.000019] ? mmu_interval_notifier_remove+0x23b/0x340 [ +0.000020] ? __pfx_mmu_interval_notifier_remove+0x10/0x10 [ +0.000017] ? kasan_save_alloc_info+0x1e/0x30 [ +0.000018] ? srso_return_thunk+0x5/0x5f [ +0.000014] ? __kasan_kmalloc+0xb1/0xc0 [ +0.000018] ? srso_return_thunk+0x5/0x5f [ +0.000013] ? __kasan_check_read+0x11/0x20 [ +0.000020] amdgpu_hmm_unregister+0x34/0x50 [amdgpu] [ +0.004695] amdgpu_gem_object_free+0x66/0xa0 [amdgpu] [ +0.004534] ? __pfx_amdgpu_gem_object_free+0x10/0x10 [amdgpu] [ +0.004291] ? do_syscall_64+0x5f/0xe0 [ +0.000023] ? srso_return_thunk+0x5/0x5f [ +0.000017] drm_gem_object_free+0x3b/0x50 [drm] [ +0.000489] amdgpu_gem_userptr_ioctl+0x306/0x500 [amdgpu] [ +0.004295] ? __pfx_amdgpu_gem_userptr_ioctl+0x10/0x10 [amdgpu] [ +0.004270] ? srso_return_thunk+0x5/0x5f [ +0.000014] ? __this_cpu_preempt_check+0x13/0x20 [ +0.000015] ? srso_return_thunk+0x5/0x5f [ +0.000013] ? sysvec_apic_timer_interrupt+0x57/0xc0 [ +0.000020] ? srso_return_thunk+0x5/0x5f [ +0.000014] ? asm_sysvec_apic_timer_interrupt+0x1b/0x20 [ +0.000022] ? drm_ioctl_kernel+0x17b/0x1f0 [drm] [ +0.000496] ? __pfx_amdgpu_gem_userptr_ioctl+0x10/0x10 [amdgpu] [ +0.004272] ? drm_ioctl_kernel+0x190/0x1f0 [drm] [ +0.000492] drm_ioctl_kernel+0x140/0x1f0 [drm] [ +0.000497] ? __pfx_amdgpu_gem_userptr_ioctl+0x10/0x10 [amdgpu] [ +0.004297] ? __pfx_drm_ioctl_kernel+0x10/0x10 [drm] [ +0.000489] ? srso_return_thunk+0x5/0x5f [ +0.000011] ? __kasan_check_write+0x14/0x20 [ +0.000016] drm_ioctl+0x3da/0x730 [drm] [ +0.000475] ? __pfx_amdgpu_gem_userptr_ioctl+0x10/0x10 [amdgpu] [ +0.004293] ? __pfx_drm_ioctl+0x10/0x10 [drm] [ +0.000506] ? __pfx_rpm_resume+0x10/0x10 [ +0.000016] ? srso_return_thunk+0x5/0x5f [ +0.000011] ? __kasan_check_write+0x14/0x20 [ +0.000010] ? srso_return_thunk+0x5/0x5f [ +0.000011] ? _raw_spin_lock_irqsave+0x99/0x100 [ +0.000015] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ +0.000014] ? srso_return_thunk+0x5/0x5f [ +0.000013] ? srso_return_thunk+0x5/0x5f [ +0.000011] ? srso_return_thunk+0x5/0x5f [ +0.000011] ? preempt_count_sub+0x18/0xc0 [ +0.000013] ? srso_return_thunk+0x5/0x5f [ +0.000010] ? _raw_spin_unlock_irqrestore+0x27/0x50 [ +0.000019] amdgpu_drm_ioctl+0x7e/0xe0 [amdgpu] [ +0.004272] __x64_sys_ioctl+0xcd/0x110 [ +0.000020] do_syscall_64+0x5f/0xe0 [ +0.000021] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ +0.000015] RIP: 0033:0x7ff9ed31a94f [ +0.000012] Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <41> 89 c0 3d 00 f0 ff ff 77 1f 48 8b 44 24 18 64 48 2b 04 25 28 00 [ +0.000013] RSP: 002b:00007fff25f66790 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ +0.000016] RAX: ffffffffffffffda RBX: 000055b3f7e133e0 RCX: 00007ff9ed31a94f [ +0.000012] RDX: 000055b3f7e133e0 RSI: 00000000c1186451 RDI: 0000000000000003 [ +0.000010] RBP: 00000000c1186451 R08: 0000000000000000 R09: 0000000000000000 [ +0.000009] R10: 0000000000000008 R11: 0000000000000246 R12: 00007fff25f66ca8 [ +0.000009] R13: 0000000000000003 R14: 000055b3f7021ba8 R15: 00007ff9ed7af040 [ +0.000024] [ +0.000007] ---[ end trace 0000000000000000 ]--- v2: Consolidate any error handling into amdgpu_hmm_register which applied to kfd_bo also. (Christian) v3: Improve syntax and comment (Christian) Cc: Christian Koenig Cc: Alex Deucher Cc: Felix Kuehling Cc: Joonkyo Jung Cc: Dokyung Song Cc: Cc: Signed-off-by: Vitaly Prosyak Reviewed-by: Christian König Signed-off-by: Alex Deucher