On 08/24/2010 02:39 PM, Daniel Kiper wrote: > Hello, > > On 08/23/2010 07:54 AM, H. Peter Anvin wrote: >> It's already applied. > > Thx. > > On Mon, Aug 23, 2010 at 10:59:19AM -0700, Yinghai Lu wrote: > [...] >>>>>> x86, apic: Fix apic=debug boot crash >>>>>> >>>>>> Fix a boot crash when apic=debug is used and the APIC is >>>>>> not properly initialized. >>>>>> >>>>>> This issue appears during Xen Dom0 kernel boot but the >>>>>> fix is generic and the crash could occur on real hardware >>>>>> as well. >>>>> >>>>> Do you have any report on real hardware? >>>>> that could not happen on real hardware. >>>> >>>> Till now no, however I think it is good idea >>>> to apply this patch now. It is not worth to wait >>>> for another null pointer dereference. >> >> no, we should add BUG_ON() etc debug info there to see why that null cfg could happen. >> because according to code, we should have null there. > > I think that BUG_ON() is too strong here because > it is "debug" function and it should work also > with let's say "invalid" data (in Xen case it is > normal because APIC state is managed directly > by hypervisor). > > Additionally, with this patch it is easy to > differentiate between cfg != NULL and > cfg == NULL. Please look below: > > cfg != NULL: > IRQ to pin mappings: > IRQ0 -> 0:2 > IRQ1 -> 0:1 > IRQ3 -> 0:3 > IRQ4 -> 0:4 > IRQ5 -> 0:5 > IRQ6 -> 0:6 > IRQ7 -> 0:7 > IRQ8 -> 0:8 > IRQ9 -> 0:9 > IRQ10 -> 0:10 > IRQ11 -> 0:11 > IRQ12 -> 0:12 > IRQ13 -> 0:13 > IRQ14 -> 0:14 > IRQ15 -> 0:15 > .................................... done. > > cfg == NULL: > IRQ to pin mappings: > .................................... done. > > If I missed something or if you have any > questions please drop me a line. I mean you should figure out why xen ops could have null cfg. Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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