An inmate serving a 34-year sentence for murder became the year’s 123rd stabbing victim at Folsom State Prison in an altercation that authorities tied to persistent racial strife at the maximum-security institution. Larry McGill, 27, convicted of first-degree murder in Los Angeles County, was stabbed in the lower back and lower arm, a prison spokesman said. McGill was reported in good condition at University Medical Center in Sacramento. Raymond Garcia, 25, serving a life sentence for first-degree murder, is suspected of attacking McGill as they were returning to a housing unit after breakfast. The prison spokesman said Garcia, who is Latino, and McGill, who is black, belong to rival gangs.