If user provides a large value (such as 0x80) for parameter prefetch_mem_region_instance in vm_bind ioctl, it will cause BIT(prefetch_region) overflow as below: " ------------[ cut here ]------------ UBSAN: shift-out-of-bounds in drivers/gpu/drm/xe/xe_vm.c:3414:7 shift exponent 128 is too large for 64-bit type 'long unsigned int' CPU: 8 UID: 0 PID: 53120 Comm: xe_exec_system_ Tainted: G W 6.18.0-rc1-lgci-xe-kernel+ #200 PREEMPT(voluntary) Tainted: [W]=WARN Hardware name: ASUS System Product Name/PRIME Z790-P WIFI, BIOS 0812 02/24/2023 Call Trace: <TASK> dump_stack_lvl+0xa0/0xc0 dump_stack+0x10/0x20 ubsan_epilogue+0x9/0x40 __ubsan_handle_shift_out_of_bounds+0x10e/0x170 ? mutex_unlock+0x12/0x20 xe_vm_bind_ioctl.cold+0x20/0x3c [xe] ... " Fix it by validating prefetch_region before the BIT() usage.
v2: Add Closes and Cc stable kernels. (Matt)
Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs") Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6478 Cc: stable@vger.kernel.org # v6.8+ Reviewed-by: Matthew Auld matthew.auld@intel.com Signed-off-by: Shuicheng Lin shuicheng.lin@intel.com --- drivers/gpu/drm/xe/xe_vm.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c index 8fb5cc6a69ec..7cac646bdf1c 100644 --- a/drivers/gpu/drm/xe/xe_vm.c +++ b/drivers/gpu/drm/xe/xe_vm.c @@ -3411,8 +3411,10 @@ static int vm_bind_ioctl_check_args(struct xe_device *xe, struct xe_vm *vm, op == DRM_XE_VM_BIND_OP_PREFETCH) || XE_IOCTL_DBG(xe, prefetch_region && op != DRM_XE_VM_BIND_OP_PREFETCH) || - XE_IOCTL_DBG(xe, (prefetch_region != DRM_XE_CONSULT_MEM_ADVISE_PREF_LOC && - !(BIT(prefetch_region) & xe->info.mem_region_mask))) || + XE_IOCTL_DBG(xe, (prefetch_region != DRM_XE_CONSULT_MEM_ADVISE_PREF_LOC && + /* Guard against undefined shift in BIT(prefetch_region) */ + (prefetch_region >= (sizeof(xe->info.mem_region_mask) * 8) || + !(BIT(prefetch_region) & xe->info.mem_region_mask)))) || XE_IOCTL_DBG(xe, obj && op == DRM_XE_VM_BIND_OP_UNMAP) || XE_IOCTL_DBG(xe, (flags & DRM_XE_VM_BIND_FLAG_MADVISE_AUTORESET) &&
On 12/11/2025 18:10, Shuicheng Lin wrote:
If user provides a large value (such as 0x80) for parameter prefetch_mem_region_instance in vm_bind ioctl, it will cause BIT(prefetch_region) overflow as below: " ------------[ cut here ]------------ UBSAN: shift-out-of-bounds in drivers/gpu/drm/xe/xe_vm.c:3414:7 shift exponent 128 is too large for 64-bit type 'long unsigned int' CPU: 8 UID: 0 PID: 53120 Comm: xe_exec_system_ Tainted: G W 6.18.0-rc1-lgci-xe-kernel+ #200 PREEMPT(voluntary) Tainted: [W]=WARN Hardware name: ASUS System Product Name/PRIME Z790-P WIFI, BIOS 0812 02/24/2023 Call Trace:
<TASK> dump_stack_lvl+0xa0/0xc0 dump_stack+0x10/0x20 ubsan_epilogue+0x9/0x40 __ubsan_handle_shift_out_of_bounds+0x10e/0x170 ? mutex_unlock+0x12/0x20 xe_vm_bind_ioctl.cold+0x20/0x3c [xe] ... " Fix it by validating prefetch_region before the BIT() usage.
v2: Add Closes and Cc stable kernels. (Matt)
Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs") Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6478 Cc: stable@vger.kernel.org # v6.8+ Reviewed-by: Matthew Auld matthew.auld@intel.com Signed-off-by: Shuicheng Lin shuicheng.lin@intel.com
Pushed with added:
Reported-by: Koen Koning koen.koning@intel.com Reported-by: Peter Senna Tschudin peter.senna@linux.intel.com
Thanks for the fix.
drivers/gpu/drm/xe/xe_vm.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c index 8fb5cc6a69ec..7cac646bdf1c 100644 --- a/drivers/gpu/drm/xe/xe_vm.c +++ b/drivers/gpu/drm/xe/xe_vm.c @@ -3411,8 +3411,10 @@ static int vm_bind_ioctl_check_args(struct xe_device *xe, struct xe_vm *vm, op == DRM_XE_VM_BIND_OP_PREFETCH) || XE_IOCTL_DBG(xe, prefetch_region && op != DRM_XE_VM_BIND_OP_PREFETCH) ||
XE_IOCTL_DBG(xe, (prefetch_region != DRM_XE_CONSULT_MEM_ADVISE_PREF_LOC &&!(BIT(prefetch_region) & xe->info.mem_region_mask))) ||
XE_IOCTL_DBG(xe, (prefetch_region != DRM_XE_CONSULT_MEM_ADVISE_PREF_LOC &&/* Guard against undefined shift in BIT(prefetch_region) */(prefetch_region >= (sizeof(xe->info.mem_region_mask) * 8) ||!(BIT(prefetch_region) & xe->info.mem_region_mask)))) ||
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