From: Shuicheng Lin <shuicheng.lin@intel.com>
Date: Mon, 24 Nov 2025 22:16:10 +0000 (+0000)
Subject: drm/xe: Prevent BIT() overflow when handling invalid prefetch region
X-Git-Tag: v6.17.10~23
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4a6f3dff466c80a258c26ff6f85670d38ef12d0e;p=thirdparty%2Fkernel%2Fstable.git

drm/xe: Prevent BIT() overflow when handling invalid prefetch region

[ Upstream commit d52dea485cd3c98cfeeb474cf66cf95df2ab142f ]

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)

Reported-by: Koen Koning <koen.koning@intel.com>
Reported-by: Peter Senna Tschudin <peter.senna@linux.intel.com>
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>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patch.msgid.link/20251112181005.2120521-2-shuicheng.lin@intel.com
(cherry picked from commit 8f565bdd14eec5611cc041dba4650e42ccdf71d9)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
(cherry picked from commit d52dea485cd3c98cfeeb474cf66cf95df2ab142f)
Signed-off-by: Shuicheng Lin <shuicheng.lin@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 30c32717a980e..ed457243e9076 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -3475,8 +3475,8 @@ 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, !(BIT(prefetch_region) &
-				       xe->info.mem_region_mask)) ||
+		    XE_IOCTL_DBG(xe, 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)) {
 			err = -EINVAL;