| From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> |
| Date: Tue, 16 Apr 2013 14:08:50 -0400 |
| Subject: xen/smp/spinlock: Fix leakage of the spinlock interrupt line for |
| every CPU online/offline |
| |
| commit 66ff0fe9e7bda8aec99985b24daad03652f7304e upstream. |
| |
| 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. |
| |
| Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> |
| [bwh: Backported to 3.2: adjust context] |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| arch/x86/xen/smp.c | 1 + |
| 1 file changed, 1 insertion(+) |
| |
| --- a/arch/x86/xen/smp.c |
| +++ b/arch/x86/xen/smp.c |
| @@ -563,6 +563,7 @@ static void xen_hvm_cpu_die(unsigned int |
| unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL); |
| unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL); |
| unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu), NULL); |
| + xen_uninit_lock_cpu(cpu); |
| xen_teardown_timer(cpu); |
| native_cpu_die(cpu); |
| } |