Executing ping -f -s 3000 IP in a certain network setup could trigger an out-of-IOMMU error, leading to a denial of service. Steps to reproduce the issue: https://bugzilla.redhat.com/show_bug.cgi?id=529137#c0 Triggering the issue would result in: PCI-DMA: Out of IOMMU space for 7222 bytes at device 0000:03:00.0 PCI-DMA: Out of IOMMU space for 7222 bytes at device 0000:03:00.0 <Repeated Many Many Times> PCI-DMA: Out of IOMMU space for 7222 bytes at device 0000:03:00.0 PCI-DMA: Out of IOMMU space for 7222 bytes at device 0000:03:00.0 HARDWARE ERROR CPU 0: Machine Check Exception: 7 Bank 4: bc0000000005001b RIP 10:<ffffffff8006b2b0> {default_idle+0x29/0x50} TSC 10116da2355 ADDR 4000000 MISC c008000001000000 This is not a software problem! Run through mcelog --ascii to decode and contact your hardware vendor Kernel panic - not syncing: Uncorrected machine check <7>APIC error on CPU2: 00(08) Upstream commits: http://git.kernel.org/linus/a866bbf6aacf95f849810079442a20be118ce905 http://git.kernel.org/linus/97d477a914b146e7e6722ded21afa79886ae8ccd References: http://bugzilla.kernel.org/show_bug.cgi?id=9468 https://bugzilla.redhat.com/show_bug.cgi?id=529137 Thanks, Eugene