CVE-2026-68261 in Linux
Zusammenfassung
von VulDB • 10.08.2026
Based on the kernel log provided, here is an analysis of the crash:
### **Summary** The system experienced a **kernel panic/oops** in the **PowerVR GPU driver (`powervr`)** while attempting to create a new graphics context. The crash occurred because the function `pvr_vm_get_fw_mem_context()` tried to access memory at address `0x0`, resulting in an **Invalid Memory Access (NULL pointer dereference or invalid page fault)**.
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### **Detailed Breakdown**
#### 1. **Crash Location & Function Call Trace** The crash happened inside the PowerVR driver: ```text Call trace: pvr_vm_get_fw_mem_context+0x0/0xc [powervr] (P) <-- CRASH HERE
pvr_context_create+0x190/0x410 [powervr]
pvr_ioctl_create_context+0x44/0x8c [powervr]
drm_ioctl_kernel+0xbc/0x124 [drm]
... ``` - **`pvr_vm_get_fw_mem_context`**: This function is likely trying to retrieve a memory context for firmware or virtualization purposes. The `+0x0/0xc` offset suggests the crash happened very early in this function (possibly at the first instruction). - **Triggered by**: A user-space application called an ioctl (`pvr_ioctl_create_context`) via DRM, which tried to create a new GPU context.
#### 2. **Register State Analysis** Key registers indicate why the access failed: ```text x0 : 0000000000000000 <-- NULL pointer passed as first argument? x19: 0000000000000000 x20: ffff00080999e680 <-- Likely the 'this' or context struct pointer ``` - **`x0 = 0`**: The first argument to `pvr_vm_get_fw_mem_context()` is zero. If this function expects a valid pointer (e.g., a device structure, memory pool, or firmware handle), passing `NULL` will cause an immediate crash when it tries to dereference it. - **`x20 = ffff00080999e680`**: This is likely the main context/device struct passed into `pvr_context_create`. The fact that this register holds a valid kernel address (`ffff...`) suggests the issue isn't with the overall device structure, but rather something **inside** it (like a missing firmware blob or uninitialized pointer field).
#### 3. **Error Type** - **`Code: ... f940a400`**: This is an ARM64 instruction encoding for `ldr x0, [x20]` (load from memory address in x20 into x0) or similar load/store operation. Since the crash happened at offset `+0x0`, it’s likely trying to read a field from a struct pointer that was invalid or NULL.
- **`(P)`** after the function name indicates this is an **invalid page fault**, meaning the kernel tried to access memory that wasn’t mapped or was protected.
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### **Likely Causes**
1. **Missing/Failed Firmware Load**: - PowerVR GPUs often require firmware blobs (e.g., `pvr_fw.bin`) loaded at boot time. If this failed, pointers within the driver’s context struct may remain NULL. When creating a new context (`pvr_context_create`), it tries to access these uninitialized/firmware-related structures and crashes.
2. **Driver Bug / Uninitialized Pointer**: - A pointer inside `struct pvr_device` or similar was not properly initialized before being used in `pvr_vm_get_fw_mem_context()`. This could happen if: - The driver probe function failed partially but didn’t clean up correctly. - There’s a race condition where the context is created before firmware initialization completes.
3. **Hardware/Device Tree Issue**: - Incorrect device tree configuration for the PowerVR GPU, leading to missing resources (memory regions, interrupts) that cause internal pointers to be NULL.
4. **Kernel Version / Driver Compatibility Bug**: - If this is a custom or out-of-tree driver (`powervr`), it may have known bugs in certain kernel versions. The `+0x0/0xc` offset suggests the crash happens immediately upon entry, possibly due to an assumption about data layout that doesn’t match reality.
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### **Recommended Actions**
1. **Check for Firmware Files**: - Ensure required PowerVR firmware blobs are present in `/lib/firmware/`. - Check `
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