In RHEL 6.1, the kernel reports "WARNING: at net/ipv4/tcp_input.c:2931 tcp_ack+0x1003/0x2300()" in /var/log/messages.

Issue

• The following warning message and subsequent backtraces are being logged in /var/log/messages.

WARNING: at net/ipv4/tcp_input.c:2931 tcp_ack+0x1003/0x2300() 
Hardware name: System x3650 M3 -[7945PDT]-
Modules linked in: ipt_MASQUERADE mpt2sas raid_class mptctl nfsd nfs_acl auth_rpcgss exportfs lockd ipt_REDIRECT xt_multiport ipt_REJECT xt_state nf_conntrack_ftp iptable_nat nf_nat nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 iptable_filter ip_tables mmfs26(U) mmfslinux(U) tracedev(U) sunrpc 8021q garp stp llc bonding ipmi_si ipmi_devintf ipmi_msghandler ib_ipoib rds_rdma rds_tcp rds ib_srp scsi_transport_srp ib_iser libiscsi scsi_transport_iscsi ib_umad ib_ucm rdma_ucm ib_uverbs rdma_cm ib_cm iw_cm ib_addr ib_sa ipv6 ext3 jbd dm_multipath dm_mod e1000e qlge ib_mthca ib_mad ib_core bnx2 sg cdc_ether usbnet mii microcode serio_raw i2c_i801 i2c_core iTCO_wdt iTCO_vendor_support ioatdma dca i7core_edac edac_core shpchp ext4 mbcache jbd2 sd_mod crc_t10dif sr_mod cdrom mptsas mptscsih mptbase scsi_transport_sas qla2xxx scsi_transport_fc scsi_tgt pata_acpi ata_generic ata_piix [last unloaded: scsi_wait_scan]
Pid: 0, comm: swapper Tainted: G        W  ----------------   2.6.32-131.27.1.el6.x86_64 #1
Call Trace:
 <IRQ>  [<ffffffff81066f27>] ? warn_slowpath_common+0x87/0xc0
 [<ffffffff81066f7a>] ? warn_slowpath_null+0x1a/0x20
 [<ffffffff814699c3>] ? tcp_ack+0x1003/0x2300
 [<ffffffff814676a1>] ? tcp_validate_incoming+0x61/0x3a0
 [<ffffffff8146b0c8>] ? tcp_rcv_established+0x408/0x800
 [<ffffffff81473093>] ? tcp_v4_do_rcv+0x2e3/0x430