Kernel 2.6.32.4 (git) with the following patches applied: af_packet.c (tpacket_snd version 3) sky2.c pskb_may_pull sky2 fix WARNING at lib/dma-debug.c check_sync Running with CONFIG_DMAR=n, system is stable. Running with the exact same source but CONFIG_DMAR=y I get the WARNING (see below) after about 36 hours of uptime (has varied from about 24 to about 48): Smolt profile: http://smolt.fedoraproject.org/show?uuid=pub_bb05c701-1e47-4b3c-9fab-54f520f39d79+ I'm also attaching dmesg.old (dmesg from the crash). Subsequent to this the system watchdog reboots the system (it's hung). Of interest: each and every time this has happened the system was under heavy RX load (win7 backup to a cifs share hosted on this server). Also, there is always a dhcp exchange of some sort preceding the event. It is possible that the event is re creatable without DMAR enabled, but I have been unsuccessful in doing so. Jan 22 05:38:36 mail dhcpd: DHCPREQUEST for 10.0.0.54 from 00:1b:78:c8:2b:8e (HPC82B8D) via eth0 Jan 22 05:38:36 mail dhcpd: DHCPACK on 10.0.0.54 to 00:1b:78:c8:2b:8e (HPC82B8D) via eth0 Jan 22 05:38:41 mail kernel: DRHD: handling fault status reg 2 Jan 22 05:38:41 mail kernel: DMAR:[DMA Read] Request device [06:00.0] fault addr ffdfdd9fe000 Jan 22 05:38:41 mail kernel: DMAR:[fault reason 06] PTE Read access is not set Jan 22 05:38:41 mail kernel: sky2 0000:06:00.0: error interrupt status=0xc0000000 Jan 22 05:38:41 mail kernel: sky2 0000:06:00.0: PCI hardware error (0x2010) Jan 22 05:39:18 mail kernel: ------------[ cut here ]------------ Jan 22 05:39:18 mail kernel: WARNING: at net/sched/sch_generic.c:261 dev_watchdog+0xf3/0x164() Jan 22 05:39:18 mail kernel: Hardware name: System Product Name Jan 22 05:39:18 mail kernel: NETDEV WATCHDOG: eth0 (sky2): transmit queue 0 timed out Jan 22 05:39:18 mail kernel: Modules linked in: cpufreq_stats ip6table_mangle ip6table_filter ip6_tables ipt_MASQUERADE iptable_nat nf_nat iptable_mangle iptable_raw appletalk psnap llc nfsd lockd nfs_acl auth_rpcgss exportfs hwmon_vid coretemp sunrpc acpi_cpufreq sit tunnel4 ipt_LOG nf_conntrack_netbios_ns nf_conntrack_ftp nf_conntrack_ipv6 xt_multiport xt_DSCP xt_dscp xt_MARK ipv6 dm_multipath kvm_intel kvm snd_hda_codec_analog snd_ens1371 gameport snd_rawmidi snd_hda_intel snd_ac97_codec snd_hda_codec snd_hwdep ac97_bus snd_seq snd_seq_device firewire_ohci snd_pcm firewire_core crc_itu_t snd_timer snd gspca_spca505 gspca_main i2c_i801 videodev v4l1_compat sky2 soundcore v4l2_compat_ioctl32 wmi snd_page_alloc asus_atk0110 hwmon pcspkr iTCO_wdt iTCO_vendor_support fbcon tileblit font bitblit softcursor raid456 async_raid6_recov async_pq raid6_pq async_xor xor async_memcpy async_tx raid1 ata_generic pata_acpi pata_marvell nouveau ttm drm_kms_helper drm agpgart fb i2c_algo_bit cfbcopyarea i2c_core cfbimgblt cfb Jan 22 05:39:18 mail kernel: fillrect [last unloaded: microcode] Jan 22 05:39:18 mail kernel: Pid: 0, comm: swapper Tainted: G W 2.6.32.4MMAPDMARAF3SKY2PSKBMAYPULL-00912-g914160d-dirty #6 Jan 22 05:39:18 mail kernel: Call Trace: Jan 22 05:39:18 mail kernel: [] warn_slowpath_common+0x7c/0x94 Jan 22 05:39:18 mail kernel: [] warn_slowpath_fmt+0x41/0x43 Jan 22 05:39:18 mail kernel: [] ? netif_tx_lock+0x44/0x6c Jan 22 05:39:18 mail kernel: [] dev_watchdog+0xf3/0x164 Jan 22 05:39:18 mail kernel: [] ? cascade+0x6a/0x84 Jan 22 05:39:18 mail kernel: [] run_timer_softirq+0x1c8/0x270 Jan 22 05:39:18 mail kernel: [] __do_softirq+0xf8/0x1cd Jan 22 05:39:18 mail kernel: [] ? tick_program_event+0x2a/0x2c Jan 22 05:39:18 mail kernel: [] call_softirq+0x1c/0x30 Jan 22 05:39:18 mail kernel: [] do_softirq+0x4b/0xa6 Jan 22 05:39:18 mail kernel: [] irq_exit+0x4a/0x8c Jan 22 05:39:18 mail kernel: [] smp_apic_timer_interrupt+0x86/0x94 Jan 22 05:39:18 mail kernel: [] apic_timer_interrupt+0x13/0x20 Jan 22 05:39:18 mail kernel: [] ? acpi_idle_enter_bm+0x256/0x28a Jan 22 05:39:18 mail kernel: [] ? acpi_idle_enter_bm+0x24f/0x28a Jan 22 05:39:18 mail kernel: [] ? cpuidle_idle_call+0x9e/0xfa Jan 22 05:39:18 mail kernel: [] ? cpu_idle+0xb4/0xf6 Jan 22 05:39:18 mail kernel: [] ? start_secondary+0x201/0x242 Jan 22 05:39:18 mail kernel: ---[ end trace 57f7151f6a5def07 ]--- Jan 22 05:39:18 mail kernel: sky2 eth0: tx timeout Jan 22 05:39:18 mail kernel: sky2 eth0: transmit ring 76 .. 35 report=76 done=76 Jan 22 05:39:18 mail kernel: sky2 eth0: disabling interface Jan 22 05:39:18 mail kernel: sky2 eth0: enabling interface Jan 22 05:39:21 mail kernel: sky2 eth0: Link is up at 1000 Mbps, full duplex, flow control both Jan 22 05:40:06 mail kernel: sky2 eth0: tx timeout Jan 22 05:40:06 mail kernel: sky2 eth0: transmit ring 3 .. 90 report=3 done=3 Jan 22 05:40:06 mail kernel: sky2 eth0: disabling interface Jan 22 05:40:06 mail kernel: sky2 eth0: enabling interface Jan 22 05:40:09 mail kernel: sky2 eth0: Link is up at 1000 Mbps, full duplex, flow control both Jan 22 05:40:30 mail abrt: Kerneloops: Reported 1 kernel oopses to Abrt Jan 22 05:40:30 mail abrtd: Directory 'kerneloops-1264156830-1' creation detected Jan 22 05:40:30 mail abrtd: Can't open file '/var/cache/abrt/kerneloops-1264156830-1/cmdline' Jan 22 05:40:30 mail abrtd: Corrupted or bad crash, deleting Jan 22 05:40:33 mail dhcpd: DHCPINFORM from 10.0.0.11 via eth0 Jan 22 05:40:33 mail dhcpd: DHCPACK to 10.0.0.11 (00:1a:92:8d:30:81) via eth0 Jan 22 05:40:36 mail dhcpd: DHCPINFORM from 10.0.0.11 via eth0 Jan 22 05:40:36 mail dhcpd: DHCPACK to 10.0.0.11 (00:1a:92:8d:30:81) via eth0 Jan 22 05:40:50 mail named[11245]: error (connection refused) resolving '173-212-207-86.hostnoc.net/A/IN': 2607:f878:0:3::12#53 Jan 22 05:40:50 mail named[11245]: error (connection refused) resolving 'NS1.HOSTNOC.NET/AAAA/IN': 2607:f878:0:3::10#53