NMI panic due to forcedeth driver mishandling MSI interrupts.

Issue

• Server with a NIC using forcedeth driver panicked with the following call traces.

eth0: too many iterations (6) in nv_nic_irq.
eth0: too many iterations (6) in nv_nic_irq.
NMI Watchdog detected LOCKUP, CPU=11, registers:
CPU 11 
Modules linked in: nfs lockd nfs_acl autofs4 sunrpc cpufreq_powersave ide_dump scsi_dump diskdump zlib_deflate dm_mod joydev button battery ac ohci_hcd ehci_hcd forcedeth ext3 jbd sata_nv libata mptscsih mptsas mptspi mptscsi mptbase sd_mod scsi_mod
Pid: 0, comm: swapper Not tainted 2.6.9-67.0.22.ELlargesmp
RIP: 0010:[<ffffffff803100c3>] <ffffffff803100c3>{.text.lock.spinlock+49}
RSP: 0018:0000010419647bc8  EFLAGS: 00000082
RAX: 0000000000000000 RBX: 0000010418e2e380 RCX: 0000000093808538
RDX: 0000010417abd280 RSI: 0000010093808538 RDI: 0000010418e2e380
RBP: 0000010418e2e380 R08: 0000000093808538 R09: 0000000000000000
R10: 0000000000000048 R11: 0000010419641fd8 R12: 0000010417abd2a0
R13: 0000000000000000 R14: 0000000000000001 R15: 00000103a13ade80
FS:  0000002a9589fb00(0000) GS:ffffffff80506f00(0000) knlGS:00000000f7e466c0
CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 0000002a9556c000 CR3: 0000000819e2a000 CR4: 00000000000006e0
Process swapper (pid: 0, threadinfo 0000010419640000, task 0000010428056030)
Stack: 000000008c000000 ffffffffa00cc9a9 0000010307f1f518 0000010418204fd8 
       0000010417abd290 0000010417abd280 000005a800000000 8000000000000001 
       0000010418e2e000 0000010418e2e000 
Call Trace:<IRQ> <ffffffffa00cc9a9>{:forcedeth:nv_start_xmit_optimized+991} 
       <ffffffff802c3699>{qdisc_restart+259} <ffffffff802d0797>{ip_finish_output2+0} 
       <ffffffff802b405f>{dev_queue_xmit+229} <ffffffff802bd976>{nf_hook_slow+184} 
       <ffffffff802d0b40>{ip_finish_output+496} <ffffffff802d0f02>{ip_queue_xmit+951} 
       <ffffffff80132789>{recalc_task_prio+337} <ffffffff80135db5>{autoremove_wake_function+9} 
       <ffffffff80132817>{activate_task+124} <ffffffff802e06d1>{tcp_transmit_skb+2064} 
       <ffffffff802e18e0>{tcp_retransmit_skb+1441} <ffffffff802e3b19>{tcp_write_timer+1059} 
       <ffffffff802e36f6>{tcp_write_timer+0} <ffffffff801406ed>{run_timer_softirq+356} 
       <ffffffff8013cd7c>{__do_softirq+88} <ffffffff8013ce25>{do_softirq+49} 
       <ffffffff80110c01>{apic_timer_interrupt+133}  <EOI> <ffffffff8010e749>{default_idle+0} 
       <ffffffff8010e769>{default_idle+32} <ffffffff8010e7dc>{cpu_idle+26} 

Code: 7e f9 e9 91 fd ff ff f3 90 83 3b 00 7e f9 e9 cf fd ff ff e8 
Kernel panic - not syncing: nmi watchdog
----------- [cut here ] --------- [please bite here ] ---------
Kernel BUG at panic:75
invalid operand: 0000 [1] SMP 
CPU 11 
Modules linked in: nfs lockd nfs_acl autofs4 sunrpc cpufreq_powersave ide_dump scsi_dump diskdump zlib_deflate dm_mod joydev button battery ac ohci_hcd ehci_hcd forcedeth ext3 jbd sata_nv libata mptscsih mptsas mptspi mptscsi mptbase sd_mod scsi_mod
Pid: 0, comm: swapper Not tainted 2.6.9-67.0.22.ELlargesmp
RIP: 0010:[<ffffffff80137fd2>] <ffffffff80137fd2>{panic+211}
RSP: 0018:0000010819e2cda8  EFLAGS: 00010086
RAX: 000000000000002c RBX: ffffffff80322f48 RCX: 0000000000000046
RDX: 0000000000025720 RSI: 0000000000000046 RDI: ffffffff803eb5c0
RBP: 0000010819e2cf58 R08: 0000000000000001 R09: ffffffff80322f48
R10: 0000000000000000 R11: 0000ffff80406a00 R12: 0000010417abd2a0
R13: 0000000000000000 R14: 0000000000000001 R15: 00000103a13ade80
FS:  0000002a9589fb00(0000) GS:ffffffff80506f00(0000) knlGS:00000000f7e466c0
CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 0000002a9556c000 CR3: 0000000819e2a000 CR4: 00000000000006e0
Process swapper (pid: 0, threadinfo 0000010419640000, task 0000010428056030)
Stack: 0000003000000008 0000010819e2ce88 0000010819e2cdc8 0000000000000013 
       0000000000000000 0000000000000046 00000000000256f4 0000000000000046 
       0000000000000001 ffffffff803255be 
Call Trace:<ffffffff80111870>{show_stack+241} <ffffffff8011199a>{show_registers+277} 
<ffffffff80111ca1>{die_nmi+130} <ffffffff8011d1c2>{nmi_watchdog_tick+210} 
<ffffffff8011256e>{default_do_nmi+112} <ffffffff8011d278>{do_nmi+115} 
<ffffffff8011117f>{paranoid_exit+0} <ffffffff803100c3>{.text.lock.spinlock+49} 
 <EOE> <IRQ> <ffffffffa00cc9a9>{:forcedeth:nv_start_xmit_optimized+991} 
       <ffffffff802c3699>{qdisc_restart+259} <ffffffff802d0797>{ip_finish_output2+0} 
       <ffffffff802b405f>{dev_queue_xmit+229} <ffffffff802bd976>{nf_hook_slow+184} 
       <ffffffff802d0b40>{ip_finish_output+496} <ffffffff802d0f02>{ip_queue_xmit+951} 
       <ffffffff80132789>{recalc_task_prio+337} <ffffffff80135db5>{autoremove_wake_function+9} 
       <ffffffff80132817>{activate_task+124} <ffffffff802e06d1>{tcp_transmit_skb+2064} 
       <ffffffff802e18e0>{tcp_retransmit_skb+1441} <ffffffff802e3b19>{tcp_write_timer+1059} 
       <ffffffff802e36f6>{tcp_write_timer+0} <ffffffff801406ed>{run_timer_softirq+356} 
       <ffffffff8013cd7c>{__do_softirq+88} <ffffffff8013ce25>{do_softirq+49} 
       <ffffffff80110c01>{apic_timer_interrupt+133}  <EOI> <ffffffff8010e749>{default_idle+0} 
       <ffffffff8010e769>{default_idle+32} <ffffffff8010e7dc>{cpu_idle+26} 

Code: 0f 0b c8 34 32 80 ff ff ff ff 4b 00 31 ff e8 87 c2 fe ff e8 
RIP <ffffffff80137fd2>{panic+211} RSP <0000010819e2cda8>