[   45.250158] audit: type=1800 audit(1549327477.591:30): pid=8043 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0
[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c.
Starting mcstransd: 
[....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c.
[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c.

Debian GNU/Linux 7 syzkaller ttyS0

syzkaller login: [   49.050712] kauditd_printk_skb: 4 callbacks suppressed
[   49.050727] audit: type=1400 audit(1549327481.411:35): avc:  denied  { map } for  pid=8216 comm="bash" path="/bin/bash" dev="sda1" ino=1457 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1
Warning: Permanently added '10.128.0.73' (ECDSA) to the list of known hosts.
[   82.984291] audit: type=1400 audit(1549327515.341:36): avc:  denied  { map } for  pid=8228 comm="syz-executor302" path="/root/syz-executor302448869" dev="sda1" ino=1426 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
[   83.033074] IPVS: ftp: loaded support on port[0] = 21
[   83.033081] IPVS: ftp: loaded support on port[0] = 21
[   83.055040] IPVS: ftp: loaded support on port[0] = 21
[   83.055649] IPVS: ftp: loaded support on port[0] = 21
[   83.072380] IPVS: ftp: loaded support on port[0] = 21
[   83.080319] IPVS: ftp: loaded support on port[0] = 21
[   83.215390] audit: type=1400 audit(1549327515.571:37): avc:  denied  { associate } for  pid=8236 comm="syz-executor302" name="syz3" scontext=unconfined_u:object_r:unlabeled_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=filesystem permissive=1
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[   83.292383] audit: type=1400 audit(1549327515.651:38): avc:  denied  { map } for  pid=8241 comm="syz-executor302" path="/dev/ashmem" dev="devtmpfs" ino=17869 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:device_t:s0 tclass=chr_file permissive=1
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[   83.340368] hrtimer: interrupt took 24534 ns
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[  102.312934] 
[  102.314601] ======================================================
[  102.320913] WARNING: possible circular locking dependency detected
[  102.327228] 5.0.0-rc5 #60 Not tainted
[  102.331022] ------------------------------------------------------
[  102.337334] syz-executor302/8918 is trying to acquire lock:
[  102.343035] 0000000019ceff1c (&mm->mmap_sem){++++}, at: __do_page_fault+0x9c2/0xd60
[  102.350850] 
[  102.350850] but task is already holding lock:
[  102.356819] 000000003968d253 (&sb->s_type->i_mutex_key#12){+.+.}, at: generic_file_write_iter+0xdf/0x610
[  102.366664] 
[  102.366664] which lock already depends on the new lock.
[  102.366664] 
[  102.374974] 
[  102.374974] the existing dependency chain (in reverse order) is:
[  102.382587] 
[  102.382587] -> #2 (&sb->s_type->i_mutex_key#12){+.+.}:
[  102.389372]        down_write+0x38/0x90
[  102.393353]        shmem_fallocate+0x15a/0xc60
[  102.397941]        ashmem_shrink_scan+0x1d7/0x4f0
[  102.402779]        ashmem_ioctl+0x2f0/0x11a0
[  102.407190]        do_vfs_ioctl+0xd6e/0x1390
[  102.411590]        ksys_ioctl+0xab/0xd0
[  102.415563]        __x64_sys_ioctl+0x73/0xb0
[  102.419970]        do_syscall_64+0x103/0x610
[  102.424375]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  102.430089] 
[  102.430089] -> #1 (ashmem_mutex){+.+.}:
[  102.435555]        __mutex_lock+0xf7/0x1310
[  102.439874]        mutex_lock_nested+0x16/0x20
[  102.444452]        ashmem_mmap+0x55/0x520
[  102.448598]        mmap_region+0xc37/0x1760
[  102.452914]        do_mmap+0x8e2/0x1080
[  102.456881]        vm_mmap_pgoff+0x1c5/0x230
[  102.461285]        ksys_mmap_pgoff+0x4aa/0x630
[  102.465860]        __x64_sys_mmap+0xe9/0x1b0
[  102.470279]        do_syscall_64+0x103/0x610
[  102.474695]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  102.480388] 
[  102.480388] -> #0 (&mm->mmap_sem){++++}:
[  102.485930]        lock_acquire+0x16f/0x3f0
[  102.490244]        down_read+0x3b/0x90
[  102.494248]        __do_page_fault+0x9c2/0xd60
[  102.498828]        do_page_fault+0x71/0x581
[  102.503145]        page_fault+0x1e/0x30
[  102.507114]        iov_iter_fault_in_readable+0x377/0x450
[  102.512644]        generic_perform_write+0x195/0x530
[  102.517745]        __generic_file_write_iter+0x25e/0x630
[  102.523188]        generic_file_write_iter+0x360/0x610
[  102.528459]        __vfs_write+0x613/0x8e0
[  102.532691]        vfs_write+0x20c/0x580
[  102.536742]        ksys_write+0xea/0x1f0
[  102.540804]        __x64_sys_write+0x73/0xb0
[  102.545212]        do_syscall_64+0x103/0x610
[  102.549617]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  102.555313] 
[  102.555313] other info that might help us debug this:
[  102.555313] 
[  102.563441] Chain exists of:
[  102.563441]   &mm->mmap_sem --> ashmem_mutex --> &sb->s_type->i_mutex_key#12
[  102.563441] 
[  102.574968]  Possible unsafe locking scenario:
[  102.574968] 
[  102.581014]        CPU0                    CPU1
[  102.585664]        ----                    ----
[  102.590315]   lock(&sb->s_type->i_mutex_key#12);
[  102.595059]                                lock(ashmem_mutex);
[  102.601016]                                lock(&sb->s_type->i_mutex_key#12);
[  102.608281]   lock(&mm->mmap_sem);
[  102.611812] 
[  102.611812]  *** DEADLOCK ***
[  102.611812] 
[  102.617859] 2 locks held by syz-executor302/8918:
[  102.622775]  #0: 00000000ac181a03 (sb_writers#6){.+.+}, at: vfs_write+0x429/0x580
[  102.630416]  #1: 000000003968d253 (&sb->s_type->i_mutex_key#12){+.+.}, at: generic_file_write_iter+0xdf/0x610
[  102.640495] 
[  102.640495] stack backtrace:
[  102.645006] CPU: 0 PID: 8918 Comm: syz-executor302 Not tainted 5.0.0-rc5 #60
[  102.652182] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[  102.661524] Call Trace:
[  102.664119]  dump_stack+0x172/0x1f0
[  102.667750]  print_circular_bug.isra.0.cold+0x1cc/0x28f
[  102.673108]  __lock_acquire+0x2f00/0x4700
[  102.677251]  ? retint_kernel+0x2d/0x2d
[  102.681135]  ? trace_hardirqs_on_caller+0x6a/0x220
[  102.686067]  ? mark_held_locks+0x100/0x100
[  102.690303]  ? iov_iter_fault_in_readable+0x377/0x450
[  102.695510]  ? cmp_ex_sort+0xd0/0xd0
[  102.699248]  ? __lock_is_held+0xb6/0x140
[  102.703322]  lock_acquire+0x16f/0x3f0
[  102.707149]  ? __do_page_fault+0x9c2/0xd60
[  102.711645]  down_read+0x3b/0x90
[  102.715005]  ? __do_page_fault+0x9c2/0xd60
[  102.719283]  __do_page_fault+0x9c2/0xd60
[  102.723356]  do_page_fault+0x71/0x581
[  102.727153]  page_fault+0x1e/0x30
[  102.730602] RIP: 0010:iov_iter_fault_in_readable+0x377/0x450
[  102.736396] Code: 89 f6 41 88 57 e0 e8 a8 29 47 fe 45 85 f6 74 c1 e9 70 fe ff ff e8 19 28 47 fe 0f 1f 00 0f ae e8 44 89 f0 48 8b 8d 68 ff ff ff <8a> 11 89 c3 0f 1f 00 41 88 57 d0 31 ff 89 de e8 75 29 47 fe 85 db
[  102.755292] RSP: 0018:ffff888098f579b8 EFLAGS: 00010293
[  102.760662] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000002020053f
[  102.767940] RDX: 0000000000000000 RSI: ffffffff8328b307 RDI: 0000000000000007
[  102.775205] RBP: ffff888098f57a58 R08: ffff888096ef8700 R09: fffff940004042af
[  102.782889] R10: fffff940004042ae R11: ffffea0002021577 R12: 0000000000001000
[  102.790152] R13: 0000000000001000 R14: 0000000000000000 R15: ffff888098f57a30
[  102.797434]  ? iov_iter_fault_in_readable+0x367/0x450
[  102.802621]  ? iov_iter_fault_in_readable+0x367/0x450
[  102.807814]  ? copy_page_from_iter+0x750/0x750
[  102.812401]  generic_perform_write+0x195/0x530
[  102.816982]  ? page_endio+0x780/0x780
[  102.820778]  ? current_time+0x140/0x140
[  102.824752]  ? lock_acquire+0x16f/0x3f0
[  102.828759]  __generic_file_write_iter+0x25e/0x630
[  102.833686]  ? __sanitizer_cov_trace_cmp8+0x18/0x20
[  102.838701]  generic_file_write_iter+0x360/0x610
[  102.843474]  ? __generic_file_write_iter+0x630/0x630
[  102.848579]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[  102.853328]  ? __sanitizer_cov_trace_const_cmp8+0x18/0x20
[  102.858872]  ? iov_iter_init+0xea/0x220
[  102.862845]  __vfs_write+0x613/0x8e0
[  102.866562]  ? kernel_read+0x120/0x120
[  102.870454]  ? rcu_read_lock_sched_held+0x110/0x130
[  102.875463]  ? rcu_sync_lockdep_assert+0x73/0xb0
[  102.880218]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[  102.885747]  ? __sb_start_write+0x1ac/0x360
[  102.890088]  vfs_write+0x20c/0x580
[  102.893646]  ksys_write+0xea/0x1f0
[  102.897180]  ? __ia32_sys_read+0xb0/0xb0
[  102.901272]  ? do_syscall_64+0x26/0x610
[  102.905240]  ? entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  102.910597]  ? do_syscall_64+0x26/0x610
[  102.914572]  __x64_sys_write+0x73/0xb0
[  102.918460]  do_syscall_64+0x103/0x610
[  102.922350]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  102.927530] RIP: 0033:0x4472e9
[  102.930729] Code: e8 3c e6 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 ab 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00
[  102.949900] RSP: 002b:00007fe2139a7da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[  102.957725] RAX: ffffffffffffffda RBX: 00000000006dcc28 RCX: 00000000004472e9
executing program
[  102.965161] RDX: 00000000fffffda2 RSI: 0000000020000540 RDI: 0000000000000005
[  102.972424] RBP: 00000000006dcc20 R08: 0000000000000000 R09: 0000000000000000
[  102.979691] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dcc2c
[  102.986955] R13: 0000000000000000 R14: 0080000080000000 R15: 20c49ba5e353f7cf
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