Bug 59971

Summary: tcp_info::tcpi_last_ack_recv = 0xFFFFFFF6
Product: Networking Reporter: _kobold
Component: OtherAssignee: Stephen Hemminger (stephen)
Status: NEW ---    
Severity: high    
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 2.6.37 Subsystem:
Regression: No Bisected commit-id:

Description _kobold 2013-06-20 11:20:20 UTC 
tcp_info::tcpi_last_ack_recv becomes "negative" sometimes. -10 msec or 1 jiffy in my case. Probably due to lack of synchronization in the kernel.

struct tcp_info tinfo = {0};
socklen_t len = sizeof(tinfo);
if (getsockopt(thesocket, SOL_TCP, TCP_INFO, (void*)&tinfo, &len) == 0)
    printf("%u\n", tinfo.tcpi_last_ack_recv);
Comment 1 _kobold 2013-06-20 11:32:47 UTC 
Reproducibility is once per 5000-7000 tries.