On Thu, 30 Jan 2014 19:06:58 -0800 Michel Lespinasse <wal...@google.com> wrote:
> Hi, > > Way back in 2010, Frederic added commit > ebc8827f75954fe315492883eee5cb3f355d547d to warn us about cases where > faults were incorrectly firing during NMI handling on x86, as the IRET > from such faults would possibly trigger nested NMIs. > > Later (2012), Salman added commit > 28696f434fef0efa97534b59986ad33b9c4df7f8 to enable nested NMI > handling. See http://lwn.net/Articles/484932/ > > So, I believe such faults nesting under NMI are not an issue anymore, > and we could revert ebc8827f75954fe315492883eee5cb3f355d547d ? Seems logical. > Background: I'm asking this because at Google we like to dump memory > regions pointed by registers in our arch_trigger_all_cpu_backtrace > handler, and this occasionally causes the vmalloc_fault in_nmi() > warning to fire. > It seems odd that x86 arch_trigger_all_cpu_backtrace() uses NMI - why didn't it use the regular old IPI? If a CPU is stuck with interrupts disable, the NMI watchdog will provide the diagnostic? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
