On Wed, Feb 06, 2008 at 02:40:40PM -0500, Vivek Goyal wrote: > On Wed, Feb 06, 2008 at 02:25:55PM -0500, Neil Horman wrote: > > Hey all- > > A hang on kdump was reported to me awhile back, only when systems died > > via nmi watchdog panic. The hang wouldn't always be in the same place, but it > > would usually be somewhere down in purgatory. In looking at the code, it > > occured to me that since, during an nmi interrupt, we won't be able to handle > > additional interrupts, that we won't be able to halt the other processors on a > > system like we try to do in machine_crash_shutdown. As such, it appears that > > leaving the other cpus running exposes us to the risk that another processor > > will encounter an error and halt the system while we are trying to boot the > > kdump kernel, and that can result in a hang. I wrote the attached patch to end > > the nmi interrupt prior to calling crash_kexec from within die_nmi, and testing > > here has proven successfull. > > > > Hi Neil, > > Why wouldn't I be able to stop other cpus if I am inside an NMI handler? I > just need to send an NMI IPI to other cpus and they should be able to > receive and handle it? > > Thanks > Vivek > Can an APIC accept an NMI while already handling an NMI? I didn't think they would interrupt one another, but rather, pend until such time as the previous NMI was cleared Neil > _______________________________________________ > kexec mailing list > kexec at lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec -- /*************************************************** *Neil Horman *Software Engineer *Red Hat, Inc. *nhorman at redhat.com *gpg keyid: 1024D / 0x92A74FA1 *http://pgp.mit.edu ***************************************************/
