Comparison Overview

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: hide VRAM sysfs attributes on GPUs without VRAM Otherwise accessing them can cause a crash.

• https://git.kernel.org/stable/c/33cc891b56b93cad1a83263eaf2e417436f70c82
• https://git.kernel.org/stable/c/39a1c8c860e32d775f29917939e87b6a7c08ebb1
• https://git.kernel.org/stable/c/a67a9f99ce1306898d7129a199d42876bc06a0f0

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: Fix NULL pointer dereference in VRAM logic for APU devices Previously, APU platforms (and other scenarios with uninitialized VRAM managers) triggered a NULL pointer dereference in `ttm_resource_manager_usage()`. The root cause is not that the `struct ttm_resource_manager *man` pointer itself is NULL, but that `man->bdev` (the backing device pointer within the manager) remains uninitialized (NULL) on APUs—since APUs lack dedicated VRAM and do not fully set up VRAM manager structures. When `ttm_resource_manager_usage()` attempts to acquire `man->bdev->lru_lock`, it dereferences the NULL `man->bdev`, leading to a kernel OOPS. 1. **amdgpu_cs.c**: Extend the existing bandwidth control check in `amdgpu_cs_get_threshold_for_moves()` to include a check for `ttm_resource_manager_used()`. If the manager is not used (uninitialized `bdev`), return 0 for migration thresholds immediately—skipping VRAM-specific logic that would trigger the NULL dereference. 2. **amdgpu_kms.c**: Update the `AMDGPU_INFO_VRAM_USAGE` ioctl and memory info reporting to use a conditional: if the manager is used, return the real VRAM usage; otherwise, return 0. This avoids accessing `man->bdev` when it is NULL. 3. **amdgpu_virt.c**: Modify the vf2pf (virtual function to physical function) data write path. Use `ttm_resource_manager_used()` to check validity: if the manager is usable, calculate `fb_usage` from VRAM usage; otherwise, set `fb_usage` to 0 (APUs have no discrete framebuffer to report). This approach is more robust than APU-specific checks because it: - Works for all scenarios where the VRAM manager is uninitialized (not just APUs), - Aligns with TTM's design by using its native helper function, - Preserves correct behavior for discrete GPUs (which have fully initialized `man->bdev` and pass the `ttm_resource_manager_used()` check). v4: use ttm_resource_manager_used(&adev->mman.vram_mgr.manager) instead of checking the adev->gmc.is_app_apu flag (Christian)

• https://git.kernel.org/stable/c/070bdce18fb12a49eb9c421e57df17d2ad29bf5f
• https://git.kernel.org/stable/c/1243e396148a65bb6c42a2b70fe43e50c16c494f
• https://git.kernel.org/stable/c/43aa61c18a3a45042b098b7a1186ffb29364002c
• https://git.kernel.org/stable/c/883f309add55060233bf11c1ea6947140372920f
• https://git.kernel.org/stable/c/e70113b741ba253886cd71dbadfe3ea444bb2f5c

In the Linux kernel, the following vulnerability has been resolved: exfat: fix improper check of dentry.stream.valid_size We found an infinite loop bug in the exFAT file system that can lead to a Denial-of-Service (DoS) condition. When a dentry in an exFAT filesystem is malformed, the following system calls — SYS_openat, SYS_ftruncate, and SYS_pwrite64 — can cause the kernel to hang. Root cause analysis shows that the size validation code in exfat_find() does not check whether dentry.stream.valid_size is negative. As a result, the system calls mentioned above can succeed and eventually trigger the DoS issue. This patch adds a check for negative dentry.stream.valid_size to prevent this vulnerability.

• https://git.kernel.org/stable/c/204b1b02ee018ba52ad2ece21fe3a8643d66a1b2
• https://git.kernel.org/stable/c/6c627bcc1896ba62ec793d0c00da74f3c93ce3ad
• https://git.kernel.org/stable/c/82ebecdc74ff555daf70b811d854b1f32a296bea

In the Linux kernel, the following vulnerability has been resolved: smb/server: fix possible memory leak in smb2_read() Memory leak occurs when ksmbd_vfs_read() fails. Fix this by adding the missing kvfree().

• https://git.kernel.org/stable/c/0797c6cf3b857cc229ab2bc69552938dcd738d78
• https://git.kernel.org/stable/c/63d8706a2c09a0c29b8b0e8a44bc7a1339685de9
• https://git.kernel.org/stable/c/6fced056d2cc8d01b326e6fcfabaacb9850b71a4
• https://git.kernel.org/stable/c/bfda5422a16651d0bf864ec468b1c216e1b10d91
• https://git.kernel.org/stable/c/f1305587731886da37a214cda812ade246c653b0

In the Linux kernel, the following vulnerability has been resolved: smb/server: fix possible refcount leak in smb2_sess_setup() Reference count of ksmbd_session will leak when session need reconnect. Fix this by adding the missing ksmbd_user_session_put().

• https://git.kernel.org/stable/c/379510a815cb2e64eb0a379cb62295d6ade65df0
• https://git.kernel.org/stable/c/6fc935f798d44a8eb8a5e6659198399fbf57b981
• https://git.kernel.org/stable/c/d37b2c81c83d6c0d5ca582f4fe73c672983f9e0d
• https://git.kernel.org/stable/c/dcc51dfe6ff26b52cac106865a172ac982d78401
• https://git.kernel.org/stable/c/e671f9bb97805771380c98de944e2ceab6949188