I'm working on a implementation of for the Go language and I've been running into a failed test case that I can't understand. The test is setup in the following manner; first write some data into a file and then read the data back using the io_uring. The simple test case of reading back all the bytes passes. However, when using two reads to read half the amount of data what I observe is the second time the ring is entered (after the first read completes successfully) is that the resulting CQE doesn't match the UserData. The test uses a monotonically increasing value for UserData and the following debug messages show that each entry has a unique UserData field. I'm guessing the ring is setup properly, however I'm not sure how to proceed. === RUN TestRingFileReadWriterRead pre enter sq head: 0 tail: 1 sq entries: [{Opcode:22 Flags:2 Ioprio:0 Fd:8 Offset:0 Addr:824634362160 Len:7 UFlags:0 UserData:1 Anon0:[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]} {Opcode:0 Flags:0 Ioprio:0 Fd:0 Offset:0 Addr:0 Len:0 UFlags:0 UserData:0 Anon0:[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]}] cq head: 0 tail: 0 cq entries: [{UserData:0 Res:0 Flags:0} {UserData:0 Res:0 Flags:0}] enter complete sq head: 1 tail: 1 sq entries: [{Opcode:22 Flags:2 Ioprio:0 Fd:8 Offset:0 Addr:824634362160 Len:7 UFlags:0 UserData:1 Anon0:[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]} {Opcode:0 Flags:0 Ioprio:0 Fd:0 Offset:0 Addr:0 Len:0 UFlags:0 UserData:0 Anon0:[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]}] cq head: 1 tail: 1 cq entries: [{UserData:1 Res:7 Flags:0} {UserData:0 Res:0 Flags:0}] pre enter sq head: 1 tail: 2 sq entries: [{Opcode:22 Flags:2 Ioprio:0 Fd:8 Offset:0 Addr:824634362160 Len:7 UFlags:0 UserData:1 Anon0:[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]} {Opcode:22 Flags:2 Ioprio:0 Fd:8 Offset:7 Addr:824634363240 Len:7 UFlags:0 UserData:2 Anon0:[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]}] cq head: 1 tail: 1 cq entries: [{UserData:1 Res:7 Flags:0} {UserData:0 Res:0 Flags:0}] enter complete sq head: 2 tail: 2 sq entries: [{Opcode:22 Flags:2 Ioprio:0 Fd:8 Offset:0 Addr:824634362160 Len:7 UFlags:0 UserData:1 Anon0:[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]} {Opcode:22 Flags:2 Ioprio:0 Fd:8 Offset:7 Addr:824634363240 Len:7 UFlags:0 UserData :2 Anon0:[0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]}] cq head: 1 tail: 2 cq entries: [{UserData:1 Res:7 Flags:0} {UserData:1 Res:7 Flags:0}]