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* [syzbot] possible deadlock in vm_mmap_pgoff
@ 2021-04-27 15:18 syzbot
       [not found] ` <20210428061522.1841-1-hdanton@sina.com>
  2021-07-23 15:16 ` syzbot
  0 siblings, 2 replies; 4+ messages in thread
From: syzbot @ 2021-04-27 15:18 UTC (permalink / raw)
  To: linux-kernel, mingo, rostedt, syzkaller-bugs

Hello,

syzbot found the following issue on:

HEAD commit:    7af08140 Revert "gcov: clang: fix clang-11+ build"
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17d57dfed00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=76c0382ceab56d34
dashboard link: https://syzkaller.appspot.com/bug?extid=f619f7c0a2a5f87694e6

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f619f7c0a2a5f87694e6@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
5.12.0-rc8-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/16055 is trying to acquire lock:
ffffffff8bfe2bc8 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x23/0xf0 kernel/trace/trace_event_perf.c:241

but task is already holding lock:
ffff88801b887258 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
ffff88801b887258 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x15c/0x290 mm/util.c:517

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&mm->mmap_lock#2){++++}-{3:3}:
       down_write_killable+0x95/0x170 kernel/locking/rwsem.c:1417
       mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
       dup_mmap kernel/fork.c:480 [inline]
       dup_mm+0x12e/0x1380 kernel/fork.c:1368
       copy_mm kernel/fork.c:1424 [inline]
       copy_process+0x2bc8/0x71a0 kernel/fork.c:2113
       kernel_clone+0xe7/0xab0 kernel/fork.c:2500
       __do_sys_clone+0xc8/0x110 kernel/fork.c:2617
       do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #2 (dup_mmap_sem){++++}-{0:0}:
       percpu_down_write+0x95/0x440 kernel/locking/percpu-rwsem.c:217
       register_for_each_vma+0x2c/0xc10 kernel/events/uprobes.c:1040
       __uprobe_register+0x5c2/0x850 kernel/events/uprobes.c:1181
       trace_uprobe_enable kernel/trace/trace_uprobe.c:1065 [inline]
       probe_event_enable+0x357/0xa00 kernel/trace/trace_uprobe.c:1134
       trace_uprobe_register+0x443/0x880 kernel/trace/trace_uprobe.c:1461
       perf_trace_event_reg kernel/trace/trace_event_perf.c:129 [inline]
       perf_trace_event_init+0x549/0xa20 kernel/trace/trace_event_perf.c:204
       perf_uprobe_init+0x16f/0x210 kernel/trace/trace_event_perf.c:336
       perf_uprobe_event_init+0xff/0x1c0 kernel/events/core.c:9754
       perf_try_init_event+0x12a/0x560 kernel/events/core.c:11071
       perf_init_event kernel/events/core.c:11123 [inline]
       perf_event_alloc.part.0+0xe3b/0x3960 kernel/events/core.c:11403
       perf_event_alloc kernel/events/core.c:11785 [inline]
       __do_sys_perf_event_open+0x647/0x2e60 kernel/events/core.c:11883
       do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #1 (&uprobe->register_rwsem){+.+.}-{3:3}:
       down_write+0x92/0x150 kernel/locking/rwsem.c:1406
       __uprobe_register+0x531/0x850 kernel/events/uprobes.c:1177
       trace_uprobe_enable kernel/trace/trace_uprobe.c:1065 [inline]
       probe_event_enable+0x357/0xa00 kernel/trace/trace_uprobe.c:1134
       trace_uprobe_register+0x443/0x880 kernel/trace/trace_uprobe.c:1461
       perf_trace_event_reg kernel/trace/trace_event_perf.c:129 [inline]
       perf_trace_event_init+0x549/0xa20 kernel/trace/trace_event_perf.c:204
       perf_uprobe_init+0x16f/0x210 kernel/trace/trace_event_perf.c:336
       perf_uprobe_event_init+0xff/0x1c0 kernel/events/core.c:9754
       perf_try_init_event+0x12a/0x560 kernel/events/core.c:11071
       perf_init_event kernel/events/core.c:11123 [inline]
       perf_event_alloc.part.0+0xe3b/0x3960 kernel/events/core.c:11403
       perf_event_alloc kernel/events/core.c:11785 [inline]
       __do_sys_perf_event_open+0x647/0x2e60 kernel/events/core.c:11883
       do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #0 (event_mutex){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:2937 [inline]
       check_prevs_add kernel/locking/lockdep.c:3060 [inline]
       validate_chain kernel/locking/lockdep.c:3675 [inline]
       __lock_acquire+0x2b14/0x54c0 kernel/locking/lockdep.c:4901
       lock_acquire kernel/locking/lockdep.c:5511 [inline]
       lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5476
       __mutex_lock_common kernel/locking/mutex.c:949 [inline]
       __mutex_lock+0x139/0x1120 kernel/locking/mutex.c:1096
       perf_trace_destroy+0x23/0xf0 kernel/trace/trace_event_perf.c:241
       _free_event+0x2ee/0x1380 kernel/events/core.c:4863
       put_event kernel/events/core.c:4957 [inline]
       perf_mmap_close+0x572/0xe10 kernel/events/core.c:6002
       remove_vma+0xae/0x170 mm/mmap.c:180
       remove_vma_list mm/mmap.c:2653 [inline]
       __do_munmap+0x74f/0x11a0 mm/mmap.c:2909
       do_munmap mm/mmap.c:2917 [inline]
       munmap_vma_range mm/mmap.c:598 [inline]
       mmap_region+0x85a/0x1730 mm/mmap.c:1750
       do_mmap+0xcff/0x11d0 mm/mmap.c:1581
       vm_mmap_pgoff+0x1b7/0x290 mm/util.c:519
       ksys_mmap_pgoff+0x49c/0x620 mm/mmap.c:1632
       do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xae

other info that might help us debug this:

Chain exists of:
  event_mutex --> dup_mmap_sem --> &mm->mmap_lock#2

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&mm->mmap_lock#2);
                               lock(dup_mmap_sem);
                               lock(&mm->mmap_lock#2);
  lock(event_mutex);

 *** DEADLOCK ***

1 lock held by syz-executor.1/16055:
 #0: ffff88801b887258 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
 #0: ffff88801b887258 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x15c/0x290 mm/util.c:517

stack backtrace:
CPU: 2 PID: 16055 Comm: syz-executor.1 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2128
 check_prev_add kernel/locking/lockdep.c:2937 [inline]
 check_prevs_add kernel/locking/lockdep.c:3060 [inline]
 validate_chain kernel/locking/lockdep.c:3675 [inline]
 __lock_acquire+0x2b14/0x54c0 kernel/locking/lockdep.c:4901
 lock_acquire kernel/locking/lockdep.c:5511 [inline]
 lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5476
 __mutex_lock_common kernel/locking/mutex.c:949 [inline]
 __mutex_lock+0x139/0x1120 kernel/locking/mutex.c:1096
 perf_trace_destroy+0x23/0xf0 kernel/trace/trace_event_perf.c:241
 _free_event+0x2ee/0x1380 kernel/events/core.c:4863
 put_event kernel/events/core.c:4957 [inline]
 perf_mmap_close+0x572/0xe10 kernel/events/core.c:6002
 remove_vma+0xae/0x170 mm/mmap.c:180
 remove_vma_list mm/mmap.c:2653 [inline]
 __do_munmap+0x74f/0x11a0 mm/mmap.c:2909
 do_munmap mm/mmap.c:2917 [inline]
 munmap_vma_range mm/mmap.c:598 [inline]
 mmap_region+0x85a/0x1730 mm/mmap.c:1750
 do_mmap+0xcff/0x11d0 mm/mmap.c:1581
 vm_mmap_pgoff+0x1b7/0x290 mm/util.c:519
 ksys_mmap_pgoff+0x49c/0x620 mm/mmap.c:1632
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x466459
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007eff7f246188 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466459
RDX: 0000000000000000 RSI: 0000000000003000 RDI: 0000000020ffc000
RBP: 00000000004bf9fb R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000011 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007fff0b32a74f R14: 00007eff7f246300 R15: 0000000000022000


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [syzbot] possible deadlock in vm_mmap_pgoff
       [not found] ` <20210428061522.1841-1-hdanton@sina.com>
@ 2021-04-28 13:30   ` Steven Rostedt
  2021-05-03 15:55     ` Peter Zijlstra
  0 siblings, 1 reply; 4+ messages in thread
From: Steven Rostedt @ 2021-04-28 13:30 UTC (permalink / raw)
  To: Hillf Danton
  Cc: syzbot, linux-kernel, Oleg Nesterov, syzkaller-bugs,
	Peter Zijlstra, Jiri Olsa

On Wed, 28 Apr 2021 14:15:22 +0800
Hillf Danton <hdanton@sina.com> wrote:

> On Tue, 27 Apr 2021 08:18:27 
> > Hello,
> > 
> > syzbot found the following issue on:
> > 
> > HEAD commit:    7af08140 Revert "gcov: clang: fix clang-11+ build"
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=17d57dfed00000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=76c0382ceab56d34
> > dashboard link: https://syzkaller.appspot.com/bug?extid=f619f7c0a2a5f87694e6
> > 
> > Unfortunately, I don't have any reproducer for this issue yet.
> > 
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+f619f7c0a2a5f87694e6@syzkaller.appspotmail.com
> > 
> > ======================================================
> > WARNING: possible circular locking dependency detected
> > 5.12.0-rc8-syzkaller #0 Not tainted
> > ------------------------------------------------------
> > syz-executor.1/16055 is trying to acquire lock:
> > ffffffff8bfe2bc8 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x23/0xf0 kernel/trace/trace_event_perf.c:241
> > 
> > but task is already holding lock:
> > ffff88801b887258 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
> > ffff88801b887258 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x15c/0x290 mm/util.c:517
> > 
> > which lock already depends on the new lock.
> > 
> > 
> > the existing dependency chain (in reverse order) is:
> >   
> > -> #3 (&mm->mmap_lock#2){++++}-{3:3}:  
> >        down_write_killable+0x95/0x170 kernel/locking/rwsem.c:1417
> >        mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
> >        dup_mmap kernel/fork.c:480 [inline]
> >        dup_mm+0x12e/0x1380 kernel/fork.c:1368
> >        copy_mm kernel/fork.c:1424 [inline]
> >        copy_process+0x2bc8/0x71a0 kernel/fork.c:2113
> >        kernel_clone+0xe7/0xab0 kernel/fork.c:2500
> >        __do_sys_clone+0xc8/0x110 kernel/fork.c:2617
> >        do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
> >        entry_SYSCALL_64_after_hwframe+0x44/0xae
> >   
> > -> #2 (dup_mmap_sem){++++}-{0:0}:  
> >        percpu_down_write+0x95/0x440 kernel/locking/percpu-rwsem.c:217
> >        register_for_each_vma+0x2c/0xc10 kernel/events/uprobes.c:1040
> >        __uprobe_register+0x5c2/0x850 kernel/events/uprobes.c:1181
> >        trace_uprobe_enable kernel/trace/trace_uprobe.c:1065 [inline]
> >        probe_event_enable+0x357/0xa00 kernel/trace/trace_uprobe.c:1134
> >        trace_uprobe_register+0x443/0x880 kernel/trace/trace_uprobe.c:1461
> >        perf_trace_event_reg kernel/trace/trace_event_perf.c:129 [inline]
> >        perf_trace_event_init+0x549/0xa20 kernel/trace/trace_event_perf.c:204
> >        perf_uprobe_init+0x16f/0x210 kernel/trace/trace_event_perf.c:336
> >        perf_uprobe_event_init+0xff/0x1c0 kernel/events/core.c:9754
> >        perf_try_init_event+0x12a/0x560 kernel/events/core.c:11071
> >        perf_init_event kernel/events/core.c:11123 [inline]
> >        perf_event_alloc.part.0+0xe3b/0x3960 kernel/events/core.c:11403
> >        perf_event_alloc kernel/events/core.c:11785 [inline]
> >        __do_sys_perf_event_open+0x647/0x2e60 kernel/events/core.c:11883
> >        do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
> >        entry_SYSCALL_64_after_hwframe+0x44/0xae
> >   
> > -> #1 (&uprobe->register_rwsem){+.+.}-{3:3}:  
> >        down_write+0x92/0x150 kernel/locking/rwsem.c:1406
> >        __uprobe_register+0x531/0x850 kernel/events/uprobes.c:1177
> >        trace_uprobe_enable kernel/trace/trace_uprobe.c:1065 [inline]
> >        probe_event_enable+0x357/0xa00 kernel/trace/trace_uprobe.c:1134
> >        trace_uprobe_register+0x443/0x880 kernel/trace/trace_uprobe.c:1461
> >        perf_trace_event_reg kernel/trace/trace_event_perf.c:129 [inline]
> >        perf_trace_event_init+0x549/0xa20 kernel/trace/trace_event_perf.c:204
> >        perf_uprobe_init+0x16f/0x210 kernel/trace/trace_event_perf.c:336
> >        perf_uprobe_event_init+0xff/0x1c0 kernel/events/core.c:9754
> >        perf_try_init_event+0x12a/0x560 kernel/events/core.c:11071
> >        perf_init_event kernel/events/core.c:11123 [inline]
> >        perf_event_alloc.part.0+0xe3b/0x3960 kernel/events/core.c:11403
> >        perf_event_alloc kernel/events/core.c:11785 [inline]
> >        __do_sys_perf_event_open+0x647/0x2e60 kernel/events/core.c:11883
> >        do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
> >        entry_SYSCALL_64_after_hwframe+0x44/0xae
> >   
> > -> #0 (event_mutex){+.+.}-{3:3}:  
> >        check_prev_add kernel/locking/lockdep.c:2937 [inline]
> >        check_prevs_add kernel/locking/lockdep.c:3060 [inline]
> >        validate_chain kernel/locking/lockdep.c:3675 [inline]
> >        __lock_acquire+0x2b14/0x54c0 kernel/locking/lockdep.c:4901
> >        lock_acquire kernel/locking/lockdep.c:5511 [inline]
> >        lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5476
> >        __mutex_lock_common kernel/locking/mutex.c:949 [inline]
> >        __mutex_lock+0x139/0x1120 kernel/locking/mutex.c:1096
> >        perf_trace_destroy+0x23/0xf0 kernel/trace/trace_event_perf.c:241
> >        _free_event+0x2ee/0x1380 kernel/events/core.c:4863
> >        put_event kernel/events/core.c:4957 [inline]
> >        perf_mmap_close+0x572/0xe10 kernel/events/core.c:6002
> >        remove_vma+0xae/0x170 mm/mmap.c:180
> >        remove_vma_list mm/mmap.c:2653 [inline]
> >        __do_munmap+0x74f/0x11a0 mm/mmap.c:2909
> >        do_munmap mm/mmap.c:2917 [inline]
> >        munmap_vma_range mm/mmap.c:598 [inline]
> >        mmap_region+0x85a/0x1730 mm/mmap.c:1750
> >        do_mmap+0xcff/0x11d0 mm/mmap.c:1581
> >        vm_mmap_pgoff+0x1b7/0x290 mm/util.c:519
> >        ksys_mmap_pgoff+0x49c/0x620 mm/mmap.c:1632
> >        do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
> >        entry_SYSCALL_64_after_hwframe+0x44/0xae
> > 
> > other info that might help us debug this:
> > 
> > Chain exists of:
> >   event_mutex --> dup_mmap_sem --> &mm->mmap_lock#2
> > 
> >  Possible unsafe locking scenario:
> > 
> >        CPU0                    CPU1
> >        ----                    ----
> >   lock(&mm->mmap_lock#2);
> >                                lock(dup_mmap_sem);
> >                                lock(&mm->mmap_lock#2);
> >   lock(event_mutex);
> > 
> >  *** DEADLOCK ***  
> 
> Break the lock chain by asking kworker to destroy perf event.
> Thoughts other than workqueue are appreciated.

I think this could cause a problem with the delay.

This is called from event->destroy()


	if (event->destroy)
		event->destroy(event);
	module_put(pmu->module);

What if this event is in that module, and we just unloaded it?

Then the workqueue would try to modify the module text that no longer
exists. Right?

I Cc'd some people that understand this code better.

-- Steve


> 
> +++ x/kernel/trace/trace_event_perf.c
> @@ -236,14 +236,22 @@ int perf_trace_init(struct perf_event *p
>  	return ret;
>  }
>  
> -void perf_trace_destroy(struct perf_event *p_event)
> +static void perf_trace_destroy_work_fn(struct work_struct *w)
>  {
> +	struct perf_event *p_event = container_of(w, struct perf_event,
> +							destroy_work);
>  	mutex_lock(&event_mutex);
>  	perf_trace_event_close(p_event);
>  	perf_trace_event_unreg(p_event);
>  	mutex_unlock(&event_mutex);
>  }
>  
> +void perf_trace_destroy(struct perf_event *p_event)
> +{
> +	INIT_WORK(&p_event->destroy_work, perf_trace_destroy_work_fn);
> +	queue_work(system_unbound_wq, &p_event->destroy_work);
> +}
> +
>  #ifdef CONFIG_KPROBE_EVENTS
>  int perf_kprobe_init(struct perf_event *p_event, bool is_retprobe)
>  {


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [syzbot] possible deadlock in vm_mmap_pgoff
  2021-04-28 13:30   ` Steven Rostedt
@ 2021-05-03 15:55     ` Peter Zijlstra
  0 siblings, 0 replies; 4+ messages in thread
From: Peter Zijlstra @ 2021-05-03 15:55 UTC (permalink / raw)
  To: Steven Rostedt
  Cc: Hillf Danton, syzbot, linux-kernel, Oleg Nesterov,
	syzkaller-bugs, Jiri Olsa

On Wed, Apr 28, 2021 at 09:30:18AM -0400, Steven Rostedt wrote:

> > Break the lock chain by asking kworker to destroy perf event.
> > Thoughts other than workqueue are appreciated.
> 
> I think this could cause a problem with the delay.
> 
> This is called from event->destroy()
> 
> 
> 	if (event->destroy)
> 		event->destroy(event);
> 	module_put(pmu->module);

The uprobe and tracepoint pmus will never be a module.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [syzbot] possible deadlock in vm_mmap_pgoff
  2021-04-27 15:18 [syzbot] possible deadlock in vm_mmap_pgoff syzbot
       [not found] ` <20210428061522.1841-1-hdanton@sina.com>
@ 2021-07-23 15:16 ` syzbot
  1 sibling, 0 replies; 4+ messages in thread
From: syzbot @ 2021-07-23 15:16 UTC (permalink / raw)
  To: hdanton, jolsa, linux-kernel, mingo, oleg, peterz, rostedt,
	syzkaller-bugs

syzbot has found a reproducer for the following issue on:

HEAD commit:    9bead1b58c4c Merge tag 'array-bounds-fixes-5.14-rc3' of gi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=155a1f5c300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5dc0e3202ae2f574
dashboard link: https://syzkaller.appspot.com/bug?extid=f619f7c0a2a5f87694e6
compiler:       Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14e2e196300000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11cc4846300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f619f7c0a2a5f87694e6@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
5.14.0-rc2-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor238/8449 is trying to acquire lock:
ffffffff8c7658e8 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x27/0xb0 kernel/trace/trace_event_perf.c:241

but task is already holding lock:
ffff888033788f28 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
ffff888033788f28 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x14d/0x2b0 mm/util.c:517

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&mm->mmap_lock#2){++++}-{3:3}:
       lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
       down_write_killable+0xaa/0x1b0 kernel/locking/rwsem.c:1417
       mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
       dup_mmap+0xde/0xed0 kernel/fork.c:484
       dup_mm+0x8c/0x310 kernel/fork.c:1379
       copy_mm kernel/fork.c:1431 [inline]
       copy_process+0x22e8/0x5b00 kernel/fork.c:2119
       kernel_clone+0x21a/0x7d0 kernel/fork.c:2509
       __do_sys_clone kernel/fork.c:2626 [inline]
       __se_sys_clone kernel/fork.c:2610 [inline]
       __x64_sys_clone+0x236/0x2b0 kernel/fork.c:2610
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #2 (dup_mmap_sem){++++}-{0:0}:
       lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
       percpu_down_write+0x52/0x2f0 kernel/locking/percpu-rwsem.c:217
       register_for_each_vma+0x32/0xc20 kernel/events/uprobes.c:1041
       __uprobe_register+0x5d4/0x860 kernel/events/uprobes.c:1182
       trace_uprobe_enable kernel/trace/trace_uprobe.c:1065 [inline]
       probe_event_enable+0x399/0xbd0 kernel/trace/trace_uprobe.c:1134
       perf_trace_event_reg kernel/trace/trace_event_perf.c:129 [inline]
       perf_trace_event_init+0x49b/0x950 kernel/trace/trace_event_perf.c:204
       perf_uprobe_init+0x138/0x1a0 kernel/trace/trace_event_perf.c:336
       perf_uprobe_event_init+0xfe/0x180 kernel/events/core.c:9875
       perf_try_init_event+0x13e/0x3d0 kernel/events/core.c:11192
       perf_init_event kernel/events/core.c:11256 [inline]
       perf_event_alloc+0x1155/0x2c10 kernel/events/core.c:11547
       __do_sys_perf_event_open kernel/events/core.c:12037 [inline]
       __se_sys_perf_event_open+0x7a6/0x4020 kernel/events/core.c:11929
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #1 (&uprobe->register_rwsem){+.+.}-{3:3}:
       lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
       down_write+0x97/0x170 kernel/locking/rwsem.c:1406
       __uprobe_register+0x4fd/0x860 kernel/events/uprobes.c:1178
       trace_uprobe_enable kernel/trace/trace_uprobe.c:1065 [inline]
       probe_event_enable+0x399/0xbd0 kernel/trace/trace_uprobe.c:1134
       perf_trace_event_reg kernel/trace/trace_event_perf.c:129 [inline]
       perf_trace_event_init+0x49b/0x950 kernel/trace/trace_event_perf.c:204
       perf_uprobe_init+0x138/0x1a0 kernel/trace/trace_event_perf.c:336
       perf_uprobe_event_init+0xfe/0x180 kernel/events/core.c:9875
       perf_try_init_event+0x13e/0x3d0 kernel/events/core.c:11192
       perf_init_event kernel/events/core.c:11256 [inline]
       perf_event_alloc+0x1155/0x2c10 kernel/events/core.c:11547
       __do_sys_perf_event_open kernel/events/core.c:12037 [inline]
       __se_sys_perf_event_open+0x7a6/0x4020 kernel/events/core.c:11929
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #0 (event_mutex){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3051 [inline]
       check_prevs_add+0x4f9/0x5b30 kernel/locking/lockdep.c:3174
       validate_chain kernel/locking/lockdep.c:3789 [inline]
       __lock_acquire+0x4476/0x6100 kernel/locking/lockdep.c:5015
       lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
       __mutex_lock_common+0x1ad/0x3770 kernel/locking/mutex.c:959
       __mutex_lock kernel/locking/mutex.c:1104 [inline]
       mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1119
       perf_trace_destroy+0x27/0xb0 kernel/trace/trace_event_perf.c:241
       _free_event+0xd4d/0x12f0 kernel/events/core.c:4959
       put_event kernel/events/core.c:5053 [inline]
       perf_mmap_close+0x8ed/0xdf0 kernel/events/core.c:6098
       remove_vma mm/mmap.c:186 [inline]
       remove_vma_list mm/mmap.c:2656 [inline]
       __do_munmap+0x1b95/0x2050 mm/mmap.c:2914
       do_munmap mm/mmap.c:2922 [inline]
       munmap_vma_range mm/mmap.c:604 [inline]
       mmap_region+0x90c/0x1df0 mm/mmap.c:1753
       do_mmap+0x89e/0x10c0 mm/mmap.c:1584
       vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:519
       ksys_mmap_pgoff+0x504/0x7b0 mm/mmap.c:1635
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae

other info that might help us debug this:

Chain exists of:
  event_mutex --> dup_mmap_sem --> &mm->mmap_lock#2

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&mm->mmap_lock#2);
                               lock(dup_mmap_sem);
                               lock(&mm->mmap_lock#2);
  lock(event_mutex);

 *** DEADLOCK ***

1 lock held by syz-executor238/8449:
 #0: ffff888033788f28 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
 #0: ffff888033788f28 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x14d/0x2b0 mm/util.c:517

stack backtrace:
CPU: 1 PID: 8449 Comm: syz-executor238 Not tainted 5.14.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1ae/0x29f lib/dump_stack.c:105
 print_circular_bug+0xb17/0xdc0 kernel/locking/lockdep.c:2009
 check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2131
 check_prev_add kernel/locking/lockdep.c:3051 [inline]
 check_prevs_add+0x4f9/0x5b30 kernel/locking/lockdep.c:3174
 validate_chain kernel/locking/lockdep.c:3789 [inline]
 __lock_acquire+0x4476/0x6100 kernel/locking/lockdep.c:5015
 lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
 __mutex_lock_common+0x1ad/0x3770 kernel/locking/mutex.c:959
 __mutex_lock kernel/locking/mutex.c:1104 [inline]
 mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1119
 perf_trace_destroy+0x27/0xb0 kernel/trace/trace_event_perf.c:241
 _free_event+0xd4d/0x12f0 kernel/events/core.c:4959
 put_event kernel/events/core.c:5053 [inline]
 perf_mmap_close+0x8ed/0xdf0 kernel/events/core.c:6098
 remove_vma mm/mmap.c:186 [inline]
 remove_vma_list mm/mmap.c:2656 [inline]
 __do_munmap+0x1b95/0x2050 mm/mmap.c:2914
 do_munmap mm/mmap.c:2922 [inline]
 munmap_vma_range mm/mmap.c:604 [inline]
 mmap_region+0x90c/0x1df0 mm/mmap.c:1753
 do_mmap+0x89e/0x10c0 mm/mmap.c:1584
 vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:519
 ksys_mmap_pgoff+0x504/0x7b0 mm/mmap.c:1635
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x44e009
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 91 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fefce402308 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00000000004cc4e8 RCX: 000000000044e009
RDX: 0000000000000000 RSI: 0000000000003000 RDI: 0000000020ffc000
RBP: 00000000004cc4e0 R08: 00


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-07-23 15:16 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-27 15:18 [syzbot] possible deadlock in vm_mmap_pgoff syzbot
     [not found] ` <20210428061522.1841-1-hdanton@sina.com>
2021-04-28 13:30   ` Steven Rostedt
2021-05-03 15:55     ` Peter Zijlstra
2021-07-23 15:16 ` syzbot

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