Re: perf_fuzzer compiled for x32 causes reboot

From: Vince Weaver <vincent.weaver@maine.edu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@redhat.com>
Subject: Re: perf_fuzzer compiled for x32 causes reboot
Date: Fri, 28 Feb 2014 10:07:29 -0500 (EST)	[thread overview]
Message-ID: <alpine.DEB.2.10.1402280957470.6727@vincent-weaver-1.um.maine.edu> (raw)
In-Reply-To: <20140228092341.12a40f7c@gandalf.local.home>

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