Add CC: Tejun Heo, Peter Zijlstra. Hi, Tejun
This is a bug whose root cause is the same as https://bugzilla.kernel.org/show_bug.cgi?id=47301. Acked-by: Lai Jiangshan <la...@cn.fujitsu.com> thanks, Lai On 09/27/2012 05:19 PM, Tang Chen wrote: > 1. cmci_rediscover() is only called by the CPU_POST_DEAD event handler, which > means the corresponding cpu has already dead. As a result, it won't be > accessed > in the for_each_online_cpu loop. > So, we could change the if(cpu == dying) statement into a BUG_ON(). > > 2. cmci_rediscover() used set_cpus_allowed_ptr() to change the current > process's > running cpu, and migrate itself to the dest cpu. But worker processes are not > allowed to be migrated. If current is a worker, the worker will be migrated to > another cpu, but the corresponding worker_pool is still on the original cpu. > > In this case, the following BUG_ON in try_to_wake_up_local() will be > triggered: > BUG_ON(rq != this_rq()); > > This will cause the kernel panic. > > This patch removes the set_cpus_allowed_ptr() call, and put the cmci > rediscover > jobs onto all the other cpus using system_wq. This could bring some delay for > the jobs. > > The following is call trace. > > [ 6155.451107] ------------[ cut here ]------------ > [ 6155.452019] kernel BUG at kernel/sched/core.c:1654! > ...... > [ 6155.452019] RIP: 0010:[<ffffffff810add15>] [<ffffffff810add15>] > try_to_wake_up_local+0x115/0x130 > ...... > [ 6155.452019] Call Trace: > [ 6155.452019] [<ffffffff8166fc14>] __schedule+0x764/0x880 > [ 6155.452019] [<ffffffff81670059>] schedule+0x29/0x70 > [ 6155.452019] [<ffffffff8166de65>] schedule_timeout+0x235/0x2d0 > [ 6155.452019] [<ffffffff810db57d>] ? mark_held_locks+0x8d/0x140 > [ 6155.452019] [<ffffffff810dd463>] ? __lock_release+0x133/0x1a0 > [ 6155.452019] [<ffffffff81671c50>] ? _raw_spin_unlock_irq+0x30/0x50 > [ 6155.452019] [<ffffffff810db8f5>] ? trace_hardirqs_on_caller+0x105/0x190 > [ 6155.452019] [<ffffffff8166fefb>] wait_for_common+0x12b/0x180 > [ 6155.452019] [<ffffffff810b0b30>] ? try_to_wake_up+0x2f0/0x2f0 > [ 6155.452019] [<ffffffff8167002d>] wait_for_completion+0x1d/0x20 > [ 6155.452019] [<ffffffff8110008a>] stop_one_cpu+0x8a/0xc0 > [ 6155.452019] [<ffffffff810abd40>] ? __migrate_task+0x1a0/0x1a0 > [ 6155.452019] [<ffffffff810a6ab8>] ? complete+0x28/0x60 > [ 6155.452019] [<ffffffff810b0fd8>] set_cpus_allowed_ptr+0x128/0x130 > [ 6155.452019] [<ffffffff81036785>] cmci_rediscover+0xf5/0x140 > [ 6155.452019] [<ffffffff816643c0>] mce_cpu_callback+0x18d/0x19d > [ 6155.452019] [<ffffffff81676187>] notifier_call_chain+0x67/0x150 > [ 6155.452019] [<ffffffff810a03de>] __raw_notifier_call_chain+0xe/0x10 > [ 6155.452019] [<ffffffff81070470>] __cpu_notify+0x20/0x40 > [ 6155.452019] [<ffffffff810704a5>] cpu_notify_nofail+0x15/0x30 > [ 6155.452019] [<ffffffff81655182>] _cpu_down+0x262/0x2e0 > [ 6155.452019] [<ffffffff81655236>] cpu_down+0x36/0x50 > [ 6155.452019] [<ffffffff813d3eaa>] acpi_processor_remove+0x50/0x11e > [ 6155.452019] [<ffffffff813a6978>] acpi_device_remove+0x90/0xb2 > [ 6155.452019] [<ffffffff8143cbec>] __device_release_driver+0x7c/0xf0 > [ 6155.452019] [<ffffffff8143cd6f>] device_release_driver+0x2f/0x50 > [ 6155.452019] [<ffffffff813a7870>] acpi_bus_remove+0x32/0x6d > [ 6155.452019] [<ffffffff813a7932>] acpi_bus_trim+0x87/0xee > [ 6155.452019] [<ffffffff813a7a21>] acpi_bus_hot_remove_device+0x88/0x16b > [ 6155.452019] [<ffffffff813a33ee>] acpi_os_execute_deferred+0x27/0x34 > [ 6155.452019] [<ffffffff81090589>] process_one_work+0x219/0x680 > [ 6155.452019] [<ffffffff81090528>] ? process_one_work+0x1b8/0x680 > [ 6155.452019] [<ffffffff813a33c7>] ? acpi_os_wait_events_complete+0x23/0x23 > [ 6155.452019] [<ffffffff810923be>] worker_thread+0x12e/0x320 > [ 6155.452019] [<ffffffff81092290>] ? manage_workers+0x110/0x110 > [ 6155.452019] [<ffffffff81098396>] kthread+0xc6/0xd0 > [ 6155.452019] [<ffffffff8167c4c4>] kernel_thread_helper+0x4/0x10 > [ 6155.452019] [<ffffffff81671f30>] ? retint_restore_args+0x13/0x13 > [ 6155.452019] [<ffffffff810982d0>] ? __init_kthread_worker+0x70/0x70 > [ 6155.452019] [<ffffffff8167c4c0>] ? gs_change+0x13/0x13 > > Signed-off-by: Tang Chen <tangc...@cn.fujitsu.com> > Signed-off-by: Miao Xie <mi...@cn.fujitsu.com> > --- > arch/x86/kernel/cpu/mcheck/mce_intel.c | 34 +++++++++++++++++-------------- > 1 files changed, 19 insertions(+), 15 deletions(-) > > diff --git a/arch/x86/kernel/cpu/mcheck/mce_intel.c > b/arch/x86/kernel/cpu/mcheck/mce_intel.c > index 38e49bc..f7d9795 100644 > --- a/arch/x86/kernel/cpu/mcheck/mce_intel.c > +++ b/arch/x86/kernel/cpu/mcheck/mce_intel.c > @@ -163,34 +163,38 @@ void cmci_clear(void) > raw_spin_unlock_irqrestore(&cmci_discover_lock, flags); > } > > +static long cmci_rediscover_work_func(void *arg) > +{ > + int banks; > + > + /* Recheck banks in case CPUs don't all have the same */ > + if (cmci_supported(&banks)) > + cmci_discover(banks, 0); > + > + return 0; > +} > + > /* > * After a CPU went down cycle through all the others and rediscover > * Must run in process context. > */ > void cmci_rediscover(int dying) > { > - int banks; > - int cpu; > - cpumask_var_t old; > + int cpu, banks; > > if (!cmci_supported(&banks)) > return; > - if (!alloc_cpumask_var(&old, GFP_KERNEL)) > - return; > - cpumask_copy(old, ¤t->cpus_allowed); > > for_each_online_cpu(cpu) { > - if (cpu == dying) > - continue; > - if (set_cpus_allowed_ptr(current, cpumask_of(cpu))) > + BUG_ON(cpu == dying); > + > + if (cpu == smp_processor_id()) { > + cmci_rediscover_work_func(NULL); > continue; > - /* Recheck banks in case CPUs don't all have the same */ > - if (cmci_supported(&banks)) > - cmci_discover(banks, 0); > - } > + } > > - set_cpus_allowed_ptr(current, old); > - free_cpumask_var(old); > + work_on_cpu(cpu, cmci_rediscover_work_func, NULL); > + } > } > > /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
