In the Linux kernel, the following vulnerability has been resolved: RDMA/hfi1: Prevent panic when SDMA is disabled If the hfi1 module is loaded with HFI1CAPSDMA off, a call to hfi1writeiter() will dereference a NULL pointer and panic. A typical stack frame is: sdmaselectuserengine [hfi1] hfi1usersdmaprocessrequest [hfi1] hfi1writeiter [hfi1] doiterreadvwritev doiterwrite vfswritev dowritev dosyscall64 The fix is to test for SDMA in hfi1writeiter() and fail the I/O with EINVAL.