CVE-2026-46220

Description

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu/sdma4: replace BUG_ON with WARN_ON in fence emission sdma_v4_0_ring_emit_fence() contains two BUG_ON(addr & 0x3) assertions that verify fence writeback addresses are dword-aligned. These assertions can be reached from unprivileged userspace via crafted DRM_IOCTL_AMDGPU_CS submissions, causing a fatal kernel panic in a scheduler worker thread. Replace both BUG_ON() calls with WARN_ON() to log the condition without crashing the kernel. A misaligned fence address at this point indicates a driver bug, but crashing the kernel is never the correct response when the assertion is reachable from userspace. The CS IOCTL path is the correct place to filter invalid submissions; the ring emission callback is too late to do anything about it. (cherry picked from commit b90250bd933afd1ba94d86d6b13821997b22b18e)

References

• https://git.kernel.org/stable/c/0b91ea46bb68abf98a082bf239092253bbd6aaa2
• https://git.kernel.org/stable/c/4f7ca00fa91daf0795ec6b3b130c5ebba1f155fe
• https://git.kernel.org/stable/c/78d2e624fa073c14970aa097adcf3ea31c157a66
• https://git.kernel.org/stable/c/a4fd82fb0757c180bf622907397c528b89a827b2
• https://git.kernel.org/stable/c/d331fb241a4602253976ddd65144a8ba2b05665d