drm/amdkfd: Fix watch_id bounds checking in debug address watch v2

{
  "id": "b05a8ea768bf1967e7b1740614a2628f8e77190a79d1454fa0206e61ee9ef501",
  "url": "https://osv.dev/vulnerability/CVE-2026-45878",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "drm/amdkfd: Fix watch_id bounds checking in debug address watch v2",
    "summary": "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); 4",
    "evidence": "osv:CVE-2026-45878",
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      "modified": "2026-10-28T02:30:36.643864193Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/2b36c0c1bcbbe15f6cfa9652084b3124c835a150",
        "https://git.kernel.org/stable/c/3c38a0f07aa2bfef2b219b1f045534ad93f85afd",
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        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45878.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-45878",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
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  "source_id": "core-osv",
  "document_id": 503983,
  "published_at": "2026-05-27T12:16:49.108+00:00"
}