FAILED: patch "[PATCH] drm/xe: Prevent BIT() overflow when handling invalid prefetch" failed to apply to 6.12-stable tree

FAILED: patch "[PATCH] drm/xe: Prevent BIT() overflow when handling invalid prefetch" failed to apply to 6.12-stable tree

[gregkh]

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x d52dea485cd3c98cfeeb474cf66cf95df2ab142f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025112408-crunching-july-9814@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d52dea485cd3c98cfeeb474cf66cf95df2ab142f Mon Sep 17 00:00:00 2001
From: Shuicheng Lin <shuicheng.lin@intel.com>
Date: Wed, 12 Nov 2025 18:10:06 +0000
Subject: [PATCH] drm/xe: Prevent BIT() overflow when handling invalid prefetch
 region

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>

diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index ccb09ef4ec9e..cdd1dc540a59 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -3369,8 +3369,10 @@ 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) &&

[PATCH 6.12.y] drm/xe: Prevent BIT() overflow when handling invalid prefetch region

[Shuicheng Lin]

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>
---
 drivers/gpu/drm/xe/xe_vm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index fc5f0e135193..30625ce691fa 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -2903,8 +2903,8 @@ static int vm_bind_ioctl_check_args(struct xe_device *xe,
 				 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;
-- 
2.49.0

Re: [PATCH 6.12.y] drm/xe: Prevent BIT() overflow when handling invalid prefetch region

[Sasha Levin]

This patch has been queued up for the 6.12 stable tree.

Subject: drm/xe: Prevent BIT() overflow when handling invalid prefetch region
Queue: 6.12

Thanks for the backport!