On Tue, 16 Apr 2013, Konrad Rzeszutek Wilk wrote: > While we don't use the spinlock interrupt line (see for details > commit f10cd522c5fbfec9ae3cc01967868c9c2401ed23 - > xen: disable PV spinlocks on HVM) - we should still do the proper > init / deinit sequence. We did not do that correctly and for the > CPU init for PVHVM guest we would allocate an interrupt line - but > failed to deallocate the old interrupt line. > > This resulted in leakage of an irq_desc but more importantly this splat > as we online an offlined CPU: > > genirq: Flags mismatch irq 71. 0002cc20 (spinlock1) vs. 0002cc20 (spinlock1) > Pid: 2542, comm: init.late Not tainted 3.9.0-rc6upstream #1 > Call Trace: > [<ffffffff811156de>] __setup_irq+0x23e/0x4a0 > [<ffffffff81194191>] ? kmem_cache_alloc_trace+0x221/0x250 > [<ffffffff811161bb>] request_threaded_irq+0xfb/0x160 > [<ffffffff8104c6f0>] ? xen_spin_trylock+0x20/0x20 > [<ffffffff813a8423>] bind_ipi_to_irqhandler+0xa3/0x160 > [<ffffffff81303758>] ? kasprintf+0x38/0x40 > [<ffffffff8104c6f0>] ? xen_spin_trylock+0x20/0x20 > [<ffffffff810cad35>] ? update_max_interval+0x15/0x40 > [<ffffffff816605db>] xen_init_lock_cpu+0x3c/0x78 > [<ffffffff81660029>] xen_hvm_cpu_notify+0x29/0x33 > [<ffffffff81676bdd>] notifier_call_chain+0x4d/0x70 > [<ffffffff810bb2a9>] __raw_notifier_call_chain+0x9/0x10 > [<ffffffff8109402b>] __cpu_notify+0x1b/0x30 > [<ffffffff8166834a>] _cpu_up+0xa0/0x14b > [<ffffffff816684ce>] cpu_up+0xd9/0xec > [<ffffffff8165f754>] store_online+0x94/0xd0 > [<ffffffff8141d15b>] dev_attr_store+0x1b/0x20 > [<ffffffff81218f44>] sysfs_write_file+0xf4/0x170 > [<ffffffff811a2864>] vfs_write+0xb4/0x130 > [<ffffffff811a302a>] sys_write+0x5a/0xa0 > [<ffffffff8167ada9>] system_call_fastpath+0x16/0x1b > cpu 1 spinlock event irq -16 > smpboot: Booting Node 0 Processor 1 APIC 0x2 > > And if one looks at the /proc/interrupts right after > offlining (CPU1): > > 70: 0 0 xen-percpu-ipi spinlock0 > 71: 0 0 xen-percpu-ipi spinlock1 > 77: 0 0 xen-percpu-ipi spinlock2 > > There is the oddity of the 'spinlock1' still being present. > > CC: stable@xxxxxxxxxxxxxxx > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> > arch/x86/xen/smp.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c > index f80e69c..22c800a 100644 > --- a/arch/x86/xen/smp.c > +++ b/arch/x86/xen/smp.c > @@ -662,6 +662,7 @@ static void xen_hvm_cpu_die(unsigned int cpu) > unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL); > unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu), NULL); > unbind_from_irqhandler(per_cpu(xen_irq_work, cpu), NULL); > + xen_uninit_lock_cpu(cpu); > xen_teardown_timer(cpu); > native_cpu_die(cpu); > } > -- > 1.8.1.4 > -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html