It happens almost every year about this time: reports begin circulating that the food stamp program is about to run out of money, and only after repeated warnings that people will soon go hungry does Congress come to the rescue at the last minute.

It began again yesterday at the Senate Appropriations Committee, which was marking up a supplemental appropriation and rescission bill passed by the House Wednesday that includes an extra $1.2 billion to get the food subsidy program through the fiscal year ending Sept. 30. Sen. Thad Cochran (R-Miss.) reported that Secretary of Agriculture John R. Block had told him the program will need another $500 million or he will have to cut back benefits by 17 percent July 1 through September.

But Cochran, who chairs the subcommittee on agriculture appropriations, also said that Office of Management and Budget Director David A. Stockman told him he is opposed to any further increases the money above the $1.2 billion requested now because members have had no formal request from the administration. In the past, administrations and Congress have always refused to permit the program that helps poor people buy food run out of money. But that was before Stockman's economy crusade.

The annual problem arises because while food stamps are not an entitlement program in that there is a cap on total funds available, it is run like one with stamps handed out to all eligible persons as long as any money remains.

The bill as passed by the House provided $18.6 billion in extra appropriations for unbudgeted expenses this year, most of it for defense, and rescinded -- or wiped out -- $12.7 billion in spending authority previously provided. Supplemental appropriations are commonplace; rescissions of this year's magnitude are not; they were sought by President Reagan. The bill as drafted by Senate Appropriations subcommittees would provide $23.2 billion in supplemental appropriations and rescind $15.4 billion, for a net of about $2 billion more in new spending authority than the House had voted.

The biggest spending cuts would be absorbed by housing assistance programs in both bills. The number of subsidized units added to housing assistance programs this year would be reduced by about 50,000 units to about 210,000.

Before sending the bill to the Senate the House added language it has attached to previous money bills forbidding use of federal employe health insurance to pay for abortions and prohibiting federal agencies from using quotas or other affirmative action to assure that minority group members are admitted to schools or jobs. Senate Appropriations Chairman Mark Hatfield (R-Ore.) will ask the Senate to reject most such riders to appropriations bills this year on grounds that the more conservative Republican-run legislative committees can be expected to report to the Senate legislative proposals on abortion and other controversial issues. The Senate committee deleted both the anti-abortion and anti-affirmative-action provisions added by the House and then sent the bill to the Senate floor without major change in the money figures.