HP systems crash with unexpected NMI when intel_iommu=on iommu=pt kernel parameters are set hpwdt

Solution Verified - Updated -


  • Kernel panic with following traces:
An NMI occurred, but unable to determine source.
Kernel panic - not syncing: An NMI occurred, please see the Integrated Management Log for details.

Pid: 0, comm: swapper Not tainted 2.6.32-358.14.1.el6.x86_64 #1
Call Trace:
 <NMI>  [<ffffffff8150d668>] ? panic+0xa7/0x16f
 [<ffffffffa00404cd>] ? hpwdt_pretimeout+0x8d/0xbc [hpwdt]
 [<ffffffff81513875>] ? notifier_call_chain+0x55/0x80
 [<ffffffff815138da>] ? atomic_notifier_call_chain+0x1a/0x20
 [<ffffffff8109cc3e>] ? notify_die+0x2e/0x30
 [<ffffffff81511597>] ? do_nmi+0x217/0x340
 [<ffffffff81510e00>] ? nmi+0x20/0x30
 [<ffffffff81307665>] ? acpi_idle_do_entry+0x5d/0x67
 <<EOE>>  [<ffffffff81307ac6>] ? acpi_idle_enter_simple+0xc6/0x14b
 [<ffffffff814153a7>] ? cpuidle_idle_call+0xa7/0x140
 [<ffffffff81009fc6>] ? cpu_idle+0xb6/0x110
 [<ffffffff815071bc>] ? start_secondary+0x2ac/0x2ef
  • IML(Integrated Management Log) logs are as follows:
An Unrecoverable System Error (NMI) has occurred (System error code 0x00000000, 0x00000000)


  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 5
  • HP ProLiant Generation 7
  • HP ProLiant Generation 8
  • HP Watchdog Timer Driver (hpwdt)
  • Kernel command line contains "intel_iommu=on iommu=pt"

Subscriber exclusive content

A Red Hat subscription provides unlimited access to our knowledgebase of over 48,000 articles and solutions.

Current Customers and Partners

Log in for full access

Log In

Welcome! Check out the Getting Started with Red Hat page for quick tours and guides for common tasks.