[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 2 of 7] KEXEC BUG: nmi_shootdown_cpus doesn't look after the interrupt flag
On 14/06/11 09:46, Jan Beulich wrote: >>>> On 13.06.11 at 19:02, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote: >> nmi_shootdown_cpus is part of the kexec path, coming from a panic, and >> as such can be called both with interrupts enabled or disabled. We >> really dont want to accidentally set IF. > Can interrupts really be enabled when entering this function? It is unlikely, but I believe there are a few codepaths which could enter this function with interrupts enabled. Either way, the last thing we need is the usual occurrence of leaving this function with interrupts enabled >> Therefore, use save/restore in preference to disable/enable. > I.e. wouldn't just removing the stray local_irq_enable() suffice? > > Jan I was trying to go for minimal changes to the Linux code. I would agree that a single disable right at the top of the crash path might be a better solution. ~Andrew >> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> >> >> diff -r 076c3034c8c7 -r 1c3d2e4d06fe xen/arch/x86/crash.c >> --- a/xen/arch/x86/crash.c Mon Jun 13 17:45:43 2011 +0100 >> +++ b/xen/arch/x86/crash.c Mon Jun 13 17:45:43 2011 +0100 >> @@ -55,9 +55,9 @@ static int crash_nmi_callback(struct cpu >> >> static void nmi_shootdown_cpus(void) >> { >> - unsigned long msecs; >> + unsigned long msecs, flags; >> >> - local_irq_disable(); >> + local_irq_save(flags); >> >> crashing_cpu = smp_processor_id(); >> local_irq_count(crashing_cpu) = 0; >> @@ -80,7 +80,7 @@ static void nmi_shootdown_cpus(void) >> __stop_this_cpu(); >> disable_IO_APIC(); >> >> - local_irq_enable(); >> + local_irq_restore(flags); >> } >> >> void machine_crash_shutdown(void) >> >> _______________________________________________ >> Xen-devel mailing list >> Xen-devel@xxxxxxxxxxxxxxxxxxx >> http://lists.xensource.com/xen-devel > > -- Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer T: +44 (0)1223 225 900, http://www.citrix.com _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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