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* KASAN: use-after-free in membarrier_mm_sync_core_before_usermode
@ 2017-11-15 10:44 Dmitry Vyukov
  2017-11-15 13:05 ` Mathieu Desnoyers
  0 siblings, 1 reply; 3+ messages in thread
From: Dmitry Vyukov @ 2017-11-15 10:44 UTC (permalink / raw)
  To: Mathieu Desnoyers, Andrew Morton, Michal Hocko,
	Greg Kroah-Hartman, Andrea Arcangeli, LKML, Ingo Molnar,
	Peter Zijlstra

Hello,

I've tried to run latest linux-next on:

commit 63fb091c80188ec51f53514d07de907c1dd3d61d
Author: Stephen Rothwell <sfr@...>
Date:   Wed Nov 15 16:44:31 2017 +1100
    Add linux-next specific files for 20171115

and it crashes during boot with:

==================================================================
BUG: KASAN: use-after-free in __read_once_size
include/linux/compiler.h:183 [inline]
BUG: KASAN: use-after-free in atomic_read
arch/x86/include/asm/atomic.h:27 [inline]
BUG: KASAN: use-after-free in membarrier_mm_sync_core_before_usermode
include/linux/sched/mm.h:216 [inline]
BUG: KASAN: use-after-free in finish_task_switch+0x61f/0x7c0
kernel/sched/core.c:2712
Read of size 4 at addr ffff880064fe5170 by task rc/1535

CPU: 0 PID: 1535 Comm: rc Not tainted 4.14.0-next-20171115 #22
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
 __read_once_size include/linux/compiler.h:183 [inline]
 atomic_read arch/x86/include/asm/atomic.h:27 [inline]
 membarrier_mm_sync_core_before_usermode include/linux/sched/mm.h:216 [inline]
 finish_task_switch+0x61f/0x7c0 kernel/sched/core.c:2712
 schedule_tail+0xe/0x100 kernel/sched/core.c:2789
 ret_from_fork+0x8/0x30 arch/x86/entry/entry_64.S:422
RIP: 0033:0x7fee2a8fdf46
RSP: 002b:00007ffddfd435b0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: 0000000000000000 RBX: 00007ffddfd435b0 RCX: 00007fee2a8fdf46
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffddfd435f0 R08: 0000000000000000 R09: 00000000000005fc
R10: 00007fee2adf59d0 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000415d62 R15: 0000000000000001

Allocated by task 1532:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3548
 dup_mm kernel/fork.c:1230 [inline]
 copy_mm+0x30a/0x1310 kernel/fork.c:1293
 copy_process.part.36+0x1f31/0x4d70 kernel/fork.c:1797
 copy_process kernel/fork.c:1610 [inline]
 _do_fork+0x1ef/0xff0 kernel/fork.c:2091
 SYSC_clone kernel/fork.c:2201 [inline]
 SyS_clone+0x37/0x50 kernel/fork.c:2195
 do_syscall_64+0x26c/0x920 arch/x86/entry/common.c:286
 return_from_SYSCALL_64+0x0/0x75

Freed by task 1535:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3492 [inline]
 kmem_cache_free+0x77/0x280 mm/slab.c:3750
 __mmdrop+0x242/0x3d0 kernel/fork.c:604
 mmdrop+0x28/0x30 kernel/fork.c:610
 finish_task_switch+0x204/0x7c0 kernel/sched/core.c:2711
 schedule_tail+0xe/0x100 kernel/sched/core.c:2789
 ret_from_fork+0x8/0x30 arch/x86/entry/entry_64.S:422

The buggy address belongs to the object at ffff880064fe4d00
 which belongs to the cache mm_struct of size 1368
The buggy address is located 1136 bytes inside of
 1368-byte region [ffff880064fe4d00, ffff880064fe5258)
The buggy address belongs to the page:
page:ffffea000193f900 count:1 mapcount:0 mapping:ffff880064fe4100
index:0x0 compound_mapcount: 0
flags: 0x1fffc0000008100(slab|head)
raw: 01fffc0000008100 ffff880064fe4100 0000000000000000 0000000100000005
raw: ffffea000193eba0 ffff88006c9f8f50 ffff88006c9f7b40 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff880064fe5000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff880064fe5080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff880064fe5100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                             ^
 ffff880064fe5180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff880064fe5200: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
==================================================================

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: KASAN: use-after-free in membarrier_mm_sync_core_before_usermode
  2017-11-15 10:44 KASAN: use-after-free in membarrier_mm_sync_core_before_usermode Dmitry Vyukov
@ 2017-11-15 13:05 ` Mathieu Desnoyers
  2017-11-15 13:31   ` Mathieu Desnoyers
  0 siblings, 1 reply; 3+ messages in thread
From: Mathieu Desnoyers @ 2017-11-15 13:05 UTC (permalink / raw)
  To: Dmitry Vyukov
  Cc: Andrew Morton, Michal Hocko, Greg Kroah-Hartman, Andrea Arcangeli,
	linux-kernel, Ingo Molnar, Peter Zijlstra

----- On Nov 15, 2017, at 5:44 AM, Dmitry Vyukov dvyukov@google.com wrote:

> Hello,
> 
> I've tried to run latest linux-next on:
> 
> commit 63fb091c80188ec51f53514d07de907c1dd3d61d
> Author: Stephen Rothwell <sfr@...>
> Date:   Wed Nov 15 16:44:31 2017 +1100
>    Add linux-next specific files for 20171115
> 
> and it crashes during boot with:

The line:

membarrier_mm_sync_core_before_usermode(mm);

should be

membarrier_mm_sync_core_before_usermode(current->mm);

Given that we want to check the flags on the next mm at this point.

I'll run this through KASAN and update the patchset.

Thanks!

Mathieu


> 
> ==================================================================
> BUG: KASAN: use-after-free in __read_once_size
> include/linux/compiler.h:183 [inline]
> BUG: KASAN: use-after-free in atomic_read
> arch/x86/include/asm/atomic.h:27 [inline]
> BUG: KASAN: use-after-free in membarrier_mm_sync_core_before_usermode
> include/linux/sched/mm.h:216 [inline]
> BUG: KASAN: use-after-free in finish_task_switch+0x61f/0x7c0
> kernel/sched/core.c:2712
> Read of size 4 at addr ffff880064fe5170 by task rc/1535
> 
> CPU: 0 PID: 1535 Comm: rc Not tainted 4.14.0-next-20171115 #22
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:17 [inline]
> dump_stack+0x194/0x257 lib/dump_stack.c:53
> print_address_description+0x73/0x250 mm/kasan/report.c:252
> kasan_report_error mm/kasan/report.c:351 [inline]
> kasan_report+0x25b/0x340 mm/kasan/report.c:409
> __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
> __read_once_size include/linux/compiler.h:183 [inline]
> atomic_read arch/x86/include/asm/atomic.h:27 [inline]
> membarrier_mm_sync_core_before_usermode include/linux/sched/mm.h:216 [inline]
> finish_task_switch+0x61f/0x7c0 kernel/sched/core.c:2712
> schedule_tail+0xe/0x100 kernel/sched/core.c:2789
> ret_from_fork+0x8/0x30 arch/x86/entry/entry_64.S:422
> RIP: 0033:0x7fee2a8fdf46
> RSP: 002b:00007ffddfd435b0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
> RAX: 0000000000000000 RBX: 00007ffddfd435b0 RCX: 00007fee2a8fdf46
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
> RBP: 00007ffddfd435f0 R08: 0000000000000000 R09: 00000000000005fc
> R10: 00007fee2adf59d0 R11: 0000000000000246 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000415d62 R15: 0000000000000001
> 
> Allocated by task 1532:
> save_stack+0x43/0xd0 mm/kasan/kasan.c:447
> set_track mm/kasan/kasan.c:459 [inline]
> kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
> kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
> kmem_cache_alloc+0x12e/0x760 mm/slab.c:3548
> dup_mm kernel/fork.c:1230 [inline]
> copy_mm+0x30a/0x1310 kernel/fork.c:1293
> copy_process.part.36+0x1f31/0x4d70 kernel/fork.c:1797
> copy_process kernel/fork.c:1610 [inline]
> _do_fork+0x1ef/0xff0 kernel/fork.c:2091
> SYSC_clone kernel/fork.c:2201 [inline]
> SyS_clone+0x37/0x50 kernel/fork.c:2195
> do_syscall_64+0x26c/0x920 arch/x86/entry/common.c:286
> return_from_SYSCALL_64+0x0/0x75
> 
> Freed by task 1535:
> save_stack+0x43/0xd0 mm/kasan/kasan.c:447
> set_track mm/kasan/kasan.c:459 [inline]
> kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
> __cache_free mm/slab.c:3492 [inline]
> kmem_cache_free+0x77/0x280 mm/slab.c:3750
> __mmdrop+0x242/0x3d0 kernel/fork.c:604
> mmdrop+0x28/0x30 kernel/fork.c:610
> finish_task_switch+0x204/0x7c0 kernel/sched/core.c:2711
> schedule_tail+0xe/0x100 kernel/sched/core.c:2789
> ret_from_fork+0x8/0x30 arch/x86/entry/entry_64.S:422
> 
> The buggy address belongs to the object at ffff880064fe4d00
> which belongs to the cache mm_struct of size 1368
> The buggy address is located 1136 bytes inside of
> 1368-byte region [ffff880064fe4d00, ffff880064fe5258)
> The buggy address belongs to the page:
> page:ffffea000193f900 count:1 mapcount:0 mapping:ffff880064fe4100
> index:0x0 compound_mapcount: 0
> flags: 0x1fffc0000008100(slab|head)
> raw: 01fffc0000008100 ffff880064fe4100 0000000000000000 0000000100000005
> raw: ffffea000193eba0 ffff88006c9f8f50 ffff88006c9f7b40 0000000000000000
> page dumped because: kasan: bad access detected
> 
> Memory state around the buggy address:
> ffff880064fe5000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff880064fe5080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>ffff880064fe5100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                                                             ^
> ffff880064fe5180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff880064fe5200: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
> ==================================================================

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: KASAN: use-after-free in membarrier_mm_sync_core_before_usermode
  2017-11-15 13:05 ` Mathieu Desnoyers
@ 2017-11-15 13:31   ` Mathieu Desnoyers
  0 siblings, 0 replies; 3+ messages in thread
From: Mathieu Desnoyers @ 2017-11-15 13:31 UTC (permalink / raw)
  To: Dmitry Vyukov
  Cc: Andrew Morton, Michal Hocko, Greg Kroah-Hartman, Andrea Arcangeli,
	linux-kernel, Ingo Molnar, Peter Zijlstra

----- On Nov 15, 2017, at 8:05 AM, Mathieu Desnoyers mathieu.desnoyers@efficios.com wrote:

> ----- On Nov 15, 2017, at 5:44 AM, Dmitry Vyukov dvyukov@google.com wrote:
> 
>> Hello,
>> 
>> I've tried to run latest linux-next on:
>> 
>> commit 63fb091c80188ec51f53514d07de907c1dd3d61d
>> Author: Stephen Rothwell <sfr@...>
>> Date:   Wed Nov 15 16:44:31 2017 +1100
>>    Add linux-next specific files for 20171115
>> 
>> and it crashes during boot with:
> 
> The line:
> 
> membarrier_mm_sync_core_before_usermode(mm);
> 
> should be
> 
> membarrier_mm_sync_core_before_usermode(current->mm);
> 
> Given that we want to check the flags on the next mm at this point.
> 
> I'll run this through KASAN and update the patchset.

Actually "mm" is prev_mm and is the right mm. I just needed
to move this call before mmdrop(mm). I'm currently booting and
running the selftests with kasan enabled and it works fine now.
I'll update the patch.

Thanks!

Mathieu



> 
> Thanks!
> 
> Mathieu
> 
> 
>> 
>> ==================================================================
>> BUG: KASAN: use-after-free in __read_once_size
>> include/linux/compiler.h:183 [inline]
>> BUG: KASAN: use-after-free in atomic_read
>> arch/x86/include/asm/atomic.h:27 [inline]
>> BUG: KASAN: use-after-free in membarrier_mm_sync_core_before_usermode
>> include/linux/sched/mm.h:216 [inline]
>> BUG: KASAN: use-after-free in finish_task_switch+0x61f/0x7c0
>> kernel/sched/core.c:2712
>> Read of size 4 at addr ffff880064fe5170 by task rc/1535
>> 
>> CPU: 0 PID: 1535 Comm: rc Not tainted 4.14.0-next-20171115 #22
>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
>> Call Trace:
>> __dump_stack lib/dump_stack.c:17 [inline]
>> dump_stack+0x194/0x257 lib/dump_stack.c:53
>> print_address_description+0x73/0x250 mm/kasan/report.c:252
>> kasan_report_error mm/kasan/report.c:351 [inline]
>> kasan_report+0x25b/0x340 mm/kasan/report.c:409
>> __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
>> __read_once_size include/linux/compiler.h:183 [inline]
>> atomic_read arch/x86/include/asm/atomic.h:27 [inline]
>> membarrier_mm_sync_core_before_usermode include/linux/sched/mm.h:216 [inline]
>> finish_task_switch+0x61f/0x7c0 kernel/sched/core.c:2712
>> schedule_tail+0xe/0x100 kernel/sched/core.c:2789
>> ret_from_fork+0x8/0x30 arch/x86/entry/entry_64.S:422
>> RIP: 0033:0x7fee2a8fdf46
>> RSP: 002b:00007ffddfd435b0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
>> RAX: 0000000000000000 RBX: 00007ffddfd435b0 RCX: 00007fee2a8fdf46
>> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
>> RBP: 00007ffddfd435f0 R08: 0000000000000000 R09: 00000000000005fc
>> R10: 00007fee2adf59d0 R11: 0000000000000246 R12: 0000000000000000
>> R13: 0000000000000000 R14: 0000000000415d62 R15: 0000000000000001
>> 
>> Allocated by task 1532:
>> save_stack+0x43/0xd0 mm/kasan/kasan.c:447
>> set_track mm/kasan/kasan.c:459 [inline]
>> kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
>> kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
>> kmem_cache_alloc+0x12e/0x760 mm/slab.c:3548
>> dup_mm kernel/fork.c:1230 [inline]
>> copy_mm+0x30a/0x1310 kernel/fork.c:1293
>> copy_process.part.36+0x1f31/0x4d70 kernel/fork.c:1797
>> copy_process kernel/fork.c:1610 [inline]
>> _do_fork+0x1ef/0xff0 kernel/fork.c:2091
>> SYSC_clone kernel/fork.c:2201 [inline]
>> SyS_clone+0x37/0x50 kernel/fork.c:2195
>> do_syscall_64+0x26c/0x920 arch/x86/entry/common.c:286
>> return_from_SYSCALL_64+0x0/0x75
>> 
>> Freed by task 1535:
>> save_stack+0x43/0xd0 mm/kasan/kasan.c:447
>> set_track mm/kasan/kasan.c:459 [inline]
>> kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
>> __cache_free mm/slab.c:3492 [inline]
>> kmem_cache_free+0x77/0x280 mm/slab.c:3750
>> __mmdrop+0x242/0x3d0 kernel/fork.c:604
>> mmdrop+0x28/0x30 kernel/fork.c:610
>> finish_task_switch+0x204/0x7c0 kernel/sched/core.c:2711
>> schedule_tail+0xe/0x100 kernel/sched/core.c:2789
>> ret_from_fork+0x8/0x30 arch/x86/entry/entry_64.S:422
>> 
>> The buggy address belongs to the object at ffff880064fe4d00
>> which belongs to the cache mm_struct of size 1368
>> The buggy address is located 1136 bytes inside of
>> 1368-byte region [ffff880064fe4d00, ffff880064fe5258)
>> The buggy address belongs to the page:
>> page:ffffea000193f900 count:1 mapcount:0 mapping:ffff880064fe4100
>> index:0x0 compound_mapcount: 0
>> flags: 0x1fffc0000008100(slab|head)
>> raw: 01fffc0000008100 ffff880064fe4100 0000000000000000 0000000100000005
>> raw: ffffea000193eba0 ffff88006c9f8f50 ffff88006c9f7b40 0000000000000000
>> page dumped because: kasan: bad access detected
>> 
>> Memory state around the buggy address:
>> ffff880064fe5000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>> ffff880064fe5080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>>ffff880064fe5100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>                                                             ^
>> ffff880064fe5180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>> ffff880064fe5200: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
>> ==================================================================
> 
> --
> Mathieu Desnoyers
> EfficiOS Inc.
> http://www.efficios.com

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2017-11-15 13:30 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2017-11-15 10:44 KASAN: use-after-free in membarrier_mm_sync_core_before_usermode Dmitry Vyukov
2017-11-15 13:05 ` Mathieu Desnoyers
2017-11-15 13:31   ` Mathieu Desnoyers

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