drm/amdgpu/sdma4: replace BUG_ON with WARN_ON in fence emission
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)
02 / AFFECTED SOFTWARE
Affected packages
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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)
05 / REFERENCES
Further evidence
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- https://git.kernel.org/stable/c/0b91ea46bb68abf98a082bf239092253bbd6aaa2
- https://git.kernel.org/stable/c/25e7d56a39657d56d1ea6d78992f7ed15dedb412
- 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
- https://git.kernel.org/stable/c/d4c56932d29773e278be6a65a5384a36c95b89a4
- https://git.kernel.org/stable/c/ecaa80318e900ca0c3f687742ede33b41cfd2f8e
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46220.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-46220