Hi, CC to Tejun Heo, and add change log:
Changes from v1 to v2: - split one single patch into two. - use WARN_ON_ONCE() but not BUG_ON(), as Tejun said. Thanks. :) On 10/19/2012 01:45 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 WARN_ON_ONCE(). 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 Tang Chen (2): Replace if statement with WARN_ON_ONCE() in cmci_rediscover(). Do not change worker's running cpu in cmci_rediscover(). arch/x86/kernel/cpu/mcheck/mce_intel.c | 34 +++++++++++++++++-------------- 1 files changed, 19 insertions(+), 15 deletions(-) -- 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/
-- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
