On Fri, 28 Feb 2014, Steven Rostedt wrote: > Interesting. Are you doing a perf function trace? > > And just in case, can you add this patch and make sure the copy is > called by NMI.
199.900682: function: trace_do_page_fault 199.900683: page_fault_user: address=__per_cpu_end ip=__per_cpu_end error_code=0x6 199.900683: function: perf_swevent_get_recursion_context 199.900684: function: perf_tp_event 199.900684: function: perf_swevent_event 199.900684: function: perf_swevent_overflow 199.900684: function: __perf_event_overflow 199.900685: function: perf_prepare_sample 199.900685: function: __perf_event_header__init_id 199.900685: function: task_tgid_nr_ns 199.900685: function: perf_event_tid 199.900686: function: __task_pid_nr_ns 199.900686: function: perf_callchain 199.900687: function: copy_from_user_nmi 199.900687: function: trace_do_page_fault 199.900687: page_fault_kernel: address=irq_stack_union ip=copy_user_generic_string error_code=0x0 199.900688: function: __do_page_fault 199.900688: function: bad_area_nosemaphore 199.900688: function: __bad_area_nosemaphore 199.900689: function: no_context 199.900689: function: fixup_exception 199.900689: function: search_exception_tables 199.900689: function: search_extable 199.900691: function: copy_user_handle_tail 199.900691: function: trace_do_page_fault 199.900691: page_fault_kernel: address=irq_stack_union ip=copy_user_handle_tail error_code=0x0 199.900691: function: __do_page_fault 199.900692: function: bad_area_nosemaphore 199.900692: function: __bad_area_nosemaphore 199.900692: function: no_context 199.900692: function: fixup_exception 199.900692: function: search_exception_tables 199.900692: function: search_extable 199.900693: function: save_stack_trace 199.900693: function: dump_trace 199.900694: function: print_context_stack 199.900694: function: __kernel_text_address 199.900694: function: is_module_text_address 199.900695: function: __module_text_address 199.900695: function: __module_address 199.900695: function: __kernel_text_address 199.900695: function: is_module_text_address 199.900696: function: __module_text_address 199.900696: function: __module_address ... 199.900705: function: __kernel_text_address 199.900809: kernel_stack: <stack trace> => perf_callchain (ffffffff810d35a2) => perf_prepare_sample (ffffffff810cfae3) => __perf_event_overflow (ffffffff810d02f4) => perf_swevent_overflow (ffffffff810d04e3) => perf_swevent_event (ffffffff810d0574) => perf_tp_event (ffffffff810d070c) => perf_trace_x86_exceptions (ffffffff810341b6) => trace_do_page_fault (ffffffff81537702) => trace_page_fault (ffffffff81534772) 199.900810: function: perf_output_begin 199.900810: function: __do_page_fault 199.900810: function: __perf_sw_event 199.900810: function: perf_swevent_get_recursion_context 199.900811: function: down_read_trylock 199.900811: function: _cond_resched 199.900811: function: find_vma 199.900811: function: bad_area 199.900812: function: up_read 199.900812: function: __bad_area_nosemaphore 199.900812: function: is_prefetch 199.900812: function: convert_ip_to_linear 199.900813: function: unhandled_signal 199.900813: function: __printk_ratelimit 199.900813: function: _raw_spin_trylock 199.900813: function: _raw_spin_unlock_irqrestore 199.900814: function: printk 199.900814: function: vprintk_emit -- 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/