drm/amdkfd: Fix watch_id bounds checking in debug address watch v2
The address watch clear code receives watch_id as an unsigned value
(u32), but some helper functions were using a signed int and checked
bits by shifting with watch_id.
If a very large watch_id is passed from userspace, it can be converted
to a negative value. This can cause invalid shifts and may access
memory outside the watch_points array.
drm/amdkfd: Fix watch_id bounds checking in debug address watch v2
Fix this by checking that watch_id is within MAX_WATCH_ADDRESSES before
using it. Also use BIT(watch_id) to test and clear bits safely.
This keeps the behavior unchanged for valid watch IDs and avoids
undefined behavior for invalid ones.
Fixes the below:
drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c:448
kfd_dbg_trap_clear_dev_address_watch() error: buffer overflow
'pdd->watch_points' 4 <= u32max user_rl='0-3,2147483648-u32max' uncapped
drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c
433 int kfd_dbg_trap_clear_dev_address_watch(struct kfd_process_device *pdd,
434 uint32_t watch_id)
435 {
436 int r;
437
438 if (!kfd_dbg_owns_dev_watch_id(pdd, watch_id))
kfd_dbg_owns_dev_watch_id() doesn't check for negative values so if
watch_id is larger than INT_MAX it leads to a buffer overflow.
(Negative shifts are undefined).
439 return -EINVAL;
440
441 if (!pdd->dev->kfd->shared_resources.enable_mes) {
442 r = debug_lock_and_unmap(pdd->dev->dqm);
443 if (r)
444 return r;
445 }
446
447 amdgpu_gfx_off_ctrl(pdd->dev->adev, false);
--> 448 pdd->watch_points[watch_id] = pdd->dev->kfd2kgd->clear_address_watch(
449 pdd->dev->adev,
450 watch_id);
v2: (as per, Jonathan Kim)
- Add early watch_id >= MAX_WATCH_ADDRESSES validation in the set path to
match the clear path.
- Drop the redundant bounds check in kfd_dbg_owns_dev_watch_id().
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Sat, 30 May 2026 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-129 CWE-191 |
Sat, 30 May 2026 11:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
cvssV3_1
|
Thu, 28 May 2026 12:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-681 | |
| References |
|
Wed, 27 May 2026 21:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-129 CWE-191 |
Wed, 27 May 2026 14:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: Fix watch_id bounds checking in debug address watch v2 The address watch clear code receives watch_id as an unsigned value (u32), but some helper functions were using a signed int and checked bits by shifting with watch_id. If a very large watch_id is passed from userspace, it can be converted to a negative value. This can cause invalid shifts and may access memory outside the watch_points array. drm/amdkfd: Fix watch_id bounds checking in debug address watch v2 Fix this by checking that watch_id is within MAX_WATCH_ADDRESSES before using it. Also use BIT(watch_id) to test and clear bits safely. This keeps the behavior unchanged for valid watch IDs and avoids undefined behavior for invalid ones. Fixes the below: drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c:448 kfd_dbg_trap_clear_dev_address_watch() error: buffer overflow 'pdd->watch_points' 4 <= u32max user_rl='0-3,2147483648-u32max' uncapped drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_debug.c 433 int kfd_dbg_trap_clear_dev_address_watch(struct kfd_process_device *pdd, 434 uint32_t watch_id) 435 { 436 int r; 437 438 if (!kfd_dbg_owns_dev_watch_id(pdd, watch_id)) kfd_dbg_owns_dev_watch_id() doesn't check for negative values so if watch_id is larger than INT_MAX it leads to a buffer overflow. (Negative shifts are undefined). 439 return -EINVAL; 440 441 if (!pdd->dev->kfd->shared_resources.enable_mes) { 442 r = debug_lock_and_unmap(pdd->dev->dqm); 443 if (r) 444 return r; 445 } 446 447 amdgpu_gfx_off_ctrl(pdd->dev->adev, false); --> 448 pdd->watch_points[watch_id] = pdd->dev->kfd2kgd->clear_address_watch( 449 pdd->dev->adev, 450 watch_id); v2: (as per, Jonathan Kim) - Add early watch_id >= MAX_WATCH_ADDRESSES validation in the set path to match the clear path. - Drop the redundant bounds check in kfd_dbg_owns_dev_watch_id(). | |
| Title | drm/amdkfd: Fix watch_id bounds checking in debug address watch v2 | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-30T10:45:44.269Z
Reserved: 2026-05-13T15:03:33.081Z
Link: CVE-2026-45878
No data.
Status : Awaiting Analysis
Published: 2026-05-27T14:17:01.547
Modified: 2026-06-17T10:52:39.377
Link: CVE-2026-45878
OpenCVE Enrichment
Updated: 2026-05-30T15:00:07Z