[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 59.994415][ T24] audit: type=1800 audit(1560197376.270:25): pid=8749 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 60.041692][ T24] audit: type=1800 audit(1560197376.270:26): pid=8749 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 60.089999][ T24] audit: type=1800 audit(1560197376.270:27): pid=8749 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.1.6' (ECDSA) to the list of known hosts. syzkaller login: [ 70.620646][ T8913] IPVS: ftp: loaded support on port[0] = 21 [ 70.625781][ T8914] IPVS: ftp: loaded support on port[0] = 21 [ 70.635828][ T8915] IPVS: ftp: loaded support on port[0] = 21 [ 70.636700][ T8912] IPVS: ftp: loaded support on port[0] = 21 [ 70.644219][ T8909] IPVS: ftp: loaded support on port[0] = 21 [ 70.649529][ T8916] IPVS: ftp: loaded support on port[0] = 21 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 74.655685][T10564] ================================================================== [ 74.663940][T10564] BUG: KASAN: use-after-free in mntput+0x91/0xa0 [ 74.670257][T10564] Read of size 4 at addr ffff8880a42e3924 by task syz-executor114/10564 [ 74.678576][T10564] [ 74.680891][T10564] CPU: 0 PID: 10564 Comm: syz-executor114 Not tainted 5.2.0-rc4 #25 [ 74.688866][T10564] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 74.698904][T10564] Call Trace: [ 74.702207][T10564] dump_stack+0x172/0x1f0 [ 74.706532][T10564] ? mntput+0x91/0xa0 [ 74.710500][T10564] print_address_description.cold+0x7c/0x20d [ 74.716485][T10564] ? mntput+0x91/0xa0 [ 74.720455][T10564] ? mntput+0x91/0xa0 [ 74.724425][T10564] __kasan_report.cold+0x1b/0x40 [ 74.729347][T10564] ? mntput+0x91/0xa0 [ 74.733317][T10564] kasan_report+0x12/0x20 [ 74.737629][T10564] __asan_report_load4_noabort+0x14/0x20 [ 74.743243][T10564] mntput+0x91/0xa0 [ 74.747130][T10564] path_put+0x50/0x70 [ 74.751095][T10564] free_fs_struct+0x25/0x70 [ 74.755603][T10564] exit_fs+0xf0/0x130 [ 74.759591][T10564] do_exit+0x8e0/0x2fa0 [ 74.763759][T10564] ? mm_update_next_owner+0x640/0x640 [ 74.769125][T10564] ? kasan_check_write+0x14/0x20 [ 74.774046][T10564] ? up_read+0xc4/0x200 [ 74.778209][T10564] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 74.783665][T10564] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 74.789121][T10564] do_group_exit+0x135/0x370 [ 74.793718][T10564] __x64_sys_exit_group+0x44/0x50 [ 74.798769][T10564] do_syscall_64+0xfd/0x680 [ 74.803264][T10564] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 74.809168][T10564] RIP: 0033:0x43ff48 [ 74.813060][T10564] Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0 0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00 [ 74.832675][T10564] RSP: 002b:00007ffe5d73cc18 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 74.841078][T10564] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff48 [ 74.849064][T10564] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 74.857029][T10564] RBP: 00000000004bfa70 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 74.865079][T10564] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 74.873217][T10564] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 74.881197][T10564] [ 74.883549][T10564] Allocated by task 10564: [ 74.887967][T10564] save_stack+0x23/0x90 [ 74.892120][T10564] __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 74.897747][T10564] kasan_slab_alloc+0xf/0x20 [ 74.902338][T10564] kmem_cache_alloc+0x11a/0x6f0 [ 74.907202][T10564] alloc_vfsmnt+0x28/0x780 [ 74.911612][T10564] vfs_create_mount+0x96/0x500 [ 74.916359][T10564] __x64_sys_fsmount+0x584/0xc80 [ 74.921368][T10564] do_syscall_64+0xfd/0x680 [ 74.925854][T10564] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 74.931992][T10564] [ 74.934315][T10564] Freed by task 9: [ 74.938059][T10564] save_stack+0x23/0x90 [ 74.942323][T10564] __kasan_slab_free+0x102/0x150 [ 74.947250][T10564] kasan_slab_free+0xe/0x10 [ 74.951867][T10564] kmem_cache_free+0x86/0x260 [ 74.956575][T10564] free_vfsmnt+0x6f/0x90 [ 74.960913][T10564] delayed_free_vfsmnt+0x16/0x20 [ 74.965860][T10564] rcu_core+0xba5/0x1500 [ 74.970087][T10564] __do_softirq+0x25c/0x94c [ 74.974590][T10564] [ 74.976908][T10564] The buggy address belongs to the object at ffff8880a42e3800 [ 74.976908][T10564] which belongs to the cache mnt_cache of size 432 [ 74.990779][T10564] The buggy address is located 292 bytes inside of [ 74.990779][T10564] 432-byte region [ffff8880a42e3800, ffff8880a42e39b0) [ 75.004033][T10564] The buggy address belongs to the page: [ 75.009681][T10564] page:ffffea000290b8c0 refcount:1 mapcount:0 mapping:ffff8880aa594940 index:0x0 [ 75.018790][T10564] flags: 0x1fffc0000000200(slab) [ 75.023738][T10564] raw: 01fffc0000000200 ffffea00027eba48 ffffea00021e3408 ffff8880aa594940 [ 75.032312][T10564] raw: 0000000000000000 ffff8880a42e3000 0000000100000008 0000000000000000 [ 75.040879][T10564] page dumped because: kasan: bad access detected [ 75.047275][T10564] [ 75.049585][T10564] Memory state around the buggy address: [ 75.055223][T10564] ffff8880a42e3800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.063270][T10564] ffff8880a42e3880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.071315][T10564] >ffff8880a42e3900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.079365][T10564] ^ [ 75.084492][T10564] ffff8880a42e3980: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc [ 75.092552][T10564] ffff8880a42e3a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 75.100603][T10564] ================================================================== [ 75.108660][T10564] Disabling lock debugging due to kernel taint [ 75.116835][T10564] Kernel panic - not syncing: panic_on_warn set ... [ 75.123800][T10564] CPU: 0 PID: 10564 Comm: syz-executor114 Tainted: G B 5.2.0-rc4 #25 [ 75.133336][T10564] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 75.143400][T10564] Call Trace: [ 75.146680][T10564] dump_stack+0x172/0x1f0 [ 75.150996][T10564] panic+0x2cb/0x744 [ 75.154884][T10564] ? __warn_printk+0xf3/0xf3 [ 75.159454][T10564] ? mntput+0x91/0xa0 [ 75.163442][T10564] ? preempt_schedule+0x4b/0x60 [ 75.168275][T10564] ? ___preempt_schedule+0x16/0x18 [ 75.173371][T10564] ? trace_hardirqs_on+0x5e/0x220 [ 75.178402][T10564] ? mntput+0x91/0xa0 [ 75.182367][T10564] end_report+0x47/0x4f [ 75.186686][T10564] ? mntput+0x91/0xa0 [ 75.190649][T10564] __kasan_report.cold+0xe/0x40 [ 75.195486][T10564] ? mntput+0x91/0xa0 [ 75.199466][T10564] kasan_report+0x12/0x20 [ 75.203959][T10564] __asan_report_load4_noabort+0x14/0x20 [ 75.209578][T10564] mntput+0x91/0xa0 [ 75.213371][T10564] path_put+0x50/0x70 [ 75.217337][T10564] free_fs_struct+0x25/0x70 [ 75.221834][T10564] exit_fs+0xf0/0x130 [ 75.225820][T10564] do_exit+0x8e0/0x2fa0 [ 75.229962][T10564] ? mm_update_next_owner+0x640/0x640 [ 75.235322][T10564] ? kasan_check_write+0x14/0x20 [ 75.240327][T10564] ? up_read+0xc4/0x200 [ 75.244465][T10564] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 75.249906][T10564] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 75.255547][T10564] do_group_exit+0x135/0x370 [ 75.260588][T10564] __x64_sys_exit_group+0x44/0x50 [ 75.265628][T10564] do_syscall_64+0xfd/0x680 [ 75.270129][T10564] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.276257][T10564] RIP: 0033:0x43ff48 [ 75.280544][T10564] Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0 0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00 [ 75.300483][T10564] RSP: 002b:00007ffe5d73cc18 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 75.308922][T10564] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff48 [ 75.316995][T10564] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 75.325193][T10564] RBP: 00000000004bfa70 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 75.333154][T10564] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 75.341136][T10564] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 75.350310][T10564] Kernel Offset: disabled [ 75.354756][T10564] Rebooting in 86400 seconds..