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From: "H. Peter Anvin" <hpa@zytor.com>
To: Vince Weaver <vincent.weaver@maine.edu>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	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: Thu, 27 Feb 2014 18:17:59 -0800	[thread overview]
Message-ID: <10e8ba5d-1642-48cd-8abb-8abcd280a6cd@email.android.com> (raw)
In-Reply-To: <alpine.DEB.2.10.1402272032140.6271@vincent-weaver-1.um.maine.edu>

Ok... I think we're definitely talking about a cr2 leak.  The reboot might be a race condition in the NMI nesting handling maybe?

On February 27, 2014 5:34:34 PM PST, Vince Weaver <vincent.weaver@maine.edu> wrote:
>On Thu, 27 Feb 2014, H. Peter Anvin wrote:
>
>> On 02/27/2014 02:31 PM, Steven Rostedt wrote:
>> > 
>> > Yeah, something is getting mesed up.
>> > 
>> 
>> What it *looks* like to me is that we try to nest the cr2
>save/restore,
>> which doesn't nest because it is a percpu variable.
>> 
>> ... except in the x86-64 case, we *ALSO* save/restore cr2 inside
>> entry_64.S, which makes the stuff in do_nmi completely redundant and
>> there for no good reason.
>> 
>> I would actually suggest we do the equivalent on i386 as well.
>> 
>> Vince, could you try this patch as an experiment?
>
>OK with your patch applied it does not segfault.
>
>The trace looks like you'd expect too:
>
>perf_fuzzer-2910  [000]   255.355331: page_fault_kernel:   
>address=irq_stack_union ip=copy_user_handle_tail error_code=0x0
>perf_fuzzer-2910  [000]   255.355331: function:               
>__do_page_fault
>perf_fuzzer-2910  [000]   255.355331: function:                  
>bad_area_nosemaphore
>perf_fuzzer-2910  [000]   255.355331: function:                     
>__bad_area_nosemaphore
>perf_fuzzer-2910  [000]   255.355332: function:                        
>no_context
>perf_fuzzer-2910  [000]   255.355332: function:                        
>   fixup_exception
>perf_fuzzer-2910  [000]   255.355332: function:                        
>      search_exception_tables
>perf_fuzzer-2910  [000]   255.355332: function:                        
>         search_extable
>perf_fuzzer-2910  [000]   255.355333: function:            
>perf_output_begin
>perf_fuzzer-2910  [000]   255.355333: bprint:              
>perf_output_begin: VMW: event type 2 config 2a st: 2c3e7
>perf_fuzzer-2910  [000]   255.355333: bprint:              
>perf_output_begin: VMW: before event->parent (nil)
>perf_fuzzer-2910  [000]   255.355334: bprint:              
>perf_output_begin: VMW: before rcu_dereference (nil)
>perf_fuzzer-2910  [000]   255.355334: function:            
>__do_page_fault
>perf_fuzzer-2910  [000]   255.355334: function:               
>down_read_trylock
>perf_fuzzer-2910  [000]   255.355334: function:               
>_cond_resched
>perf_fuzzer-2910  [000]   255.355335: function:                find_vma
>perf_fuzzer-2910  [000]   255.355335: function:               
>handle_mm_fault
>perf_fuzzer-2910  [000]   255.355335: function:                  
>__do_fault
>perf_fuzzer-2910  [000]   255.355335: bputs:               
>perf_mmap_fault: VMW: perf_mmap_fault
>perf_fuzzer-2910  [000]   255.355336: bprint:              
>perf_mmap_fault: VMW: perf_mmap_fault 0xffff8800cba6a980
>perf_fuzzer-2910  [000]   255.355336: function:            
>perf_mmap_to_page
>perf_fuzzer-2910  [000]   255.355336: function:            
>_cond_resched
>perf_fuzzer-2910  [000]   255.355336: function:                     
>unlock_page
>perf_fuzzer-2910  [000]   255.355336: function:                        
>page_waitqueue
>perf_fuzzer-2910  [000]   255.355337: function:                        
>__wake_up_bit
>perf_fuzzer-2910  [000]   255.355337: bputs:               
>perf_mmap_fault: VMW: perf_mmap_fault
>perf_fuzzer-2910  [000]   255.355337: function:            
>_cond_resched
>perf_fuzzer-2910  [000]   255.355337: function:                     
>_raw_spin_lock
>perf_fuzzer-2910  [000]   255.355337: function:                     
>page_add_file_rmap
>perf_fuzzer-2910  [000]   255.355338: function:                        
>__inc_zone_page_state
>perf_fuzzer-2910  [000]   255.355338: function:                        
>   __inc_zone_state
>perf_fuzzer-2910  [000]   255.355338: function:                     
>set_page_dirty
>perf_fuzzer-2910  [000]   255.355338: function:                        
>page_mapping
>perf_fuzzer-2910  [000]   255.355338: function:                        
>anon_set_page_dirty
>perf_fuzzer-2910  [000]   255.355339: function:                     
>unlock_page
>
>
>Vince

-- 
Sent from my mobile phone.  Please pardon brevity and lack of formatting.

  reply	other threads:[~2014-02-28  2:18 UTC|newest]

Thread overview: 115+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-21 20:25 perf_fuzzer causes reboot Vince Weaver
2014-02-21 22:13 ` perf_fuzzer compiled for x32 " Vince Weaver
2014-02-21 22:34   ` Vince Weaver
2014-02-22  4:50     ` Vince Weaver
2014-02-22  5:03       ` H. Peter Anvin
2014-02-22  6:26       ` H. Peter Anvin
2014-02-23  5:18         ` Vince Weaver
2014-02-23  5:24           ` H. Peter Anvin
2014-02-23  6:07           ` H. Peter Anvin
2014-02-23 14:05             ` Vince Weaver
2014-02-24  3:02               ` Vince Weaver
2014-02-24  5:22                 ` H. Peter Anvin
2014-02-24 15:35                   ` Vince Weaver
2014-02-24 16:34                     ` Vince Weaver
2014-02-24 16:47                       ` H. Peter Anvin
2014-02-24 17:10                         ` Vince Weaver
2014-02-24 17:25                           ` Peter Zijlstra
2014-02-24 17:32                             ` Vince Weaver
2014-02-24 17:40                               ` H. Peter Anvin
2014-02-24 18:00                                 ` Vince Weaver
2014-02-24 18:07                                   ` Vince Weaver
2014-02-24 18:34                                     ` H. Peter Anvin
2014-02-24 19:13                                       ` Steven Rostedt
2014-02-24 19:15                                         ` H. Peter Anvin
2014-02-24 19:30                                         ` Peter Zijlstra
2014-02-24 19:32                                           ` Steven Rostedt
2014-02-25  3:49                                           ` H. Peter Anvin
2014-02-25 14:07                                             ` Vince Weaver
2014-02-25 14:34                                               ` H. Peter Anvin
2014-02-25 14:43                                                 ` Steven Rostedt
2014-02-25 15:33                                                   ` Vince Weaver
2014-02-26 15:06                                                     ` Vince Weaver
2014-02-27 22:06                                                       ` Vince Weaver
2014-02-27 22:31                                                         ` Steven Rostedt
2014-02-27 22:52                                                           ` H. Peter Anvin
2014-02-27 23:30                                                             ` Steven Rostedt
2014-02-27 23:46                                                               ` H. Peter Anvin
2014-02-28  1:00                                                                 ` Vince Weaver
2014-02-28 20:34                                                                   ` Paul E. McKenney
2014-02-28 20:47                                                                     ` Steven Rostedt
2014-02-28 20:54                                                                       ` Peter Zijlstra
2014-02-28 21:17                                                                         ` Paul E. McKenney
2014-02-28 21:27                                                                           ` Peter Zijlstra
2014-02-28 21:51                                                                             ` Paul E. McKenney
2014-02-28 21:55                                                                               ` Peter Zijlstra
2014-02-28 22:05                                                                                 ` Steven Rostedt
2014-02-28 22:23                                                                                   ` Paul E. McKenney
2014-02-28  1:34                                                             ` Vince Weaver
2014-02-28  2:17                                                               ` H. Peter Anvin [this message]
2014-02-28  2:57                                                               ` Steven Rostedt
2014-02-28 11:11                                                                 ` Peter Zijlstra
2014-02-28 13:37                                                                   ` Steven Rostedt
2014-02-28 14:15                                                                 ` Vince Weaver
2014-02-28 14:23                                                                   ` Steven Rostedt
2014-02-28 15:07                                                                     ` Vince Weaver
2014-02-28 15:13                                                                       ` H. Peter Anvin
2014-02-28 15:40                                                                         ` Peter Zijlstra
2014-02-28 16:15                                                                           ` H. Peter Anvin
2014-02-28 16:29                                                                             ` Steven Rostedt
2014-02-28 19:33                                                                               ` [PATCH] x86: Rename copy_from_user_nmi() to copy_from_user_trace() Steven Rostedt
2014-02-28 20:46                                                                                 ` Peter Zijlstra
2014-02-28 20:51                                                                                   ` Steven Rostedt
2014-02-28 20:58                                                                                     ` Peter Zijlstra
2014-02-28 21:01                                                                                   ` Steven Rostedt
2014-02-28 21:17                                                                                     ` Peter Zijlstra
2014-02-28 20:56                                                                               ` perf_fuzzer compiled for x32 causes reboot Peter Zijlstra
2014-02-28 21:06                                                                                 ` Steven Rostedt
2014-03-01  9:16                                                                                   ` Ingo Molnar
2014-03-01  9:50                                                                                     ` Borislav Petkov
2014-03-01 16:50                                                                                       ` H. Peter Anvin
2014-03-04 23:05                                                                                         ` Borislav Petkov
2014-03-03  9:16                                                                                     ` Peter Zijlstra
2014-02-28 20:55                                                                             ` Peter Zijlstra
2014-02-28 15:20                                                                       ` Steven Rostedt
2014-02-28 15:30                                                                         ` Steven Rostedt
2014-02-28 20:38                                                                       ` H. Peter Anvin
2014-02-28 20:46                                                                         ` Steven Rostedt
2014-02-28 21:18                                                                         ` Vince Weaver
2014-02-28 21:30                                                                           ` Steven Rostedt
2014-02-28 23:34                                                                             ` Vince Weaver
2014-03-01  0:43                                                                               ` H. Peter Anvin
2014-03-01  3:36                                                                               ` Steven Rostedt
2014-03-01 16:24                                                                                 ` Andi Kleen
2014-03-02 15:34                                                                                   ` Vince Weaver
2014-03-02 16:02                                                                                 ` Vince Weaver
2014-02-28  9:39                                                           ` Peter Zijlstra
2014-02-24 17:40                               ` Peter Zijlstra
2014-02-24 17:41                               ` Vince Weaver
2014-02-24 17:42                                 ` H. Peter Anvin
2014-02-24 17:52                             ` H. Peter Anvin
2014-02-28 15:33 [PATCH] x86 trace: Fix page fault tracing bug Jiri Olsa
2014-02-28 15:47 ` Peter Zijlstra
2014-02-28 16:05   ` [PATCHv2] " Jiri Olsa
2014-02-28 16:11     ` H. Peter Anvin
2014-02-28 16:23       ` Steven Rostedt
2014-02-28 16:15     ` Steven Rostedt
2014-03-05  0:03     ` [tip:x86/urgent] x86, trace: Fix CR2 corruption when tracing page faults tip-bot for Jiri Olsa
2014-03-05 11:14       ` Peter Zijlstra
2014-03-05 12:20         ` Steven Rostedt
2014-03-05 12:25           ` Peter Zijlstra
2014-03-05 12:33             ` Steven Rostedt
2014-03-05 12:54               ` Peter Zijlstra
2014-03-05 13:02                 ` Peter Zijlstra
2014-03-05 13:07                   ` Peter Zijlstra
2014-03-05 12:36             ` Peter Zijlstra
2014-03-05 13:00               ` Steven Rostedt
2014-03-05 13:08                 ` Peter Zijlstra
2014-03-05 21:37                   ` H. Peter Anvin
2014-03-06  8:40                     ` Peter Zijlstra
2014-03-06 11:02                       ` Steven Rostedt
2014-03-06 14:53                         ` [PATCH] x86: Further robustify CR2 handling vs tracing Peter Zijlstra
2014-03-07 23:07                           ` [tip:x86/urgent] x86, trace: " tip-bot for Peter Zijlstra
2014-02-28 15:47 ` [PATCH] x86 trace: Fix page fault tracing bug Jiri Olsa
2014-02-28 16:00   ` Steven Rostedt
2014-02-28 16:01 ` Steven Rostedt

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