[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 66.719194][ T27] audit: type=1800 audit(1560161921.214:25): pid=8472 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 66.765922][ T27] audit: type=1800 audit(1560161921.214:26): pid=8472 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 66.820595][ T27] audit: type=1800 audit(1560161921.224:27): pid=8472 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 '10.128.0.244' (ECDSA) to the list of known hosts. syzkaller login: [ 76.863119][ T8636] IPVS: ftp: loaded support on port[0] = 21 [ 76.864758][ T8638] IPVS: ftp: loaded support on port[0] = 21 [ 76.877010][ T8637] IPVS: ftp: loaded support on port[0] = 21 [ 76.879287][ T8635] IPVS: ftp: loaded support on port[0] = 21 [ 76.886959][ T8634] IPVS: ftp: loaded support on port[0] = 21 [ 76.891726][ T8631] 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 [ 77.769470][ T8955] ================================================================== [ 77.777786][ T8955] BUG: KASAN: use-after-free in mntput+0x91/0xa0 [ 77.784108][ T8955] Read of size 4 at addr ffff88808f661124 by task syz-executor817/8955 [ 77.792325][ T8955] [ 77.794657][ T8955] CPU: 1 PID: 8955 Comm: syz-executor817 Not tainted 5.2.0-rc4 #18 [ 77.802533][ T8955] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 77.812576][ T8955] Call Trace: [ 77.815874][ T8955] dump_stack+0x172/0x1f0 [ 77.820183][ T8955] ? mntput+0x91/0xa0 [ 77.824161][ T8955] print_address_description.cold+0x7c/0x20d [ 77.830124][ T8955] ? mntput+0x91/0xa0 [ 77.834088][ T8955] ? mntput+0x91/0xa0 [ 77.838051][ T8955] __kasan_report.cold+0x1b/0x40 [ 77.842973][ T8955] ? mntput+0x91/0xa0 [ 77.846956][ T8955] kasan_report+0x12/0x20 [ 77.851267][ T8955] __asan_report_load4_noabort+0x14/0x20 [ 77.856878][ T8955] mntput+0x91/0xa0 [ 77.860676][ T8955] path_put+0x50/0x70 [ 77.864652][ T8955] free_fs_struct+0x25/0x70 [ 77.869135][ T8955] exit_fs+0xf0/0x130 [ 77.873113][ T8955] do_exit+0x8e0/0x2fa0 [ 77.877269][ T8955] ? __do_page_fault+0x623/0xda0 [ 77.882291][ T8955] ? mm_update_next_owner+0x640/0x640 [ 77.887649][ T8955] ? kasan_check_read+0x11/0x20 [ 77.892484][ T8955] ? kasan_check_write+0x14/0x20 [ 77.897408][ T8955] ? up_read+0xc4/0x200 [ 77.901573][ T8955] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 77.907018][ T8955] do_group_exit+0x135/0x370 [ 77.911593][ T8955] __ia32_sys_exit_group+0x44/0x50 [ 77.916699][ T8955] do_fast_syscall_32+0x27b/0xd7d [ 77.921736][ T8955] entry_SYSENTER_compat+0x70/0x7f [ 77.926831][ T8955] RIP: 0023:0xf7f16849 [ 77.930880][ T8955] Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 [ 77.950463][ T8955] RSP: 002b:00000000ffe4f85c EFLAGS: 00000296 ORIG_RAX: 00000000000000fc [ 77.958861][ T8955] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000080ed2b8 [ 77.966815][ T8955] RDX: 0000000000000000 RSI: 00000000080d71fc RDI: 00000000080ed2c0 [ 77.974765][ T8955] RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 [ 77.982713][ T8955] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 77.990665][ T8955] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 77.998630][ T8955] [ 78.000970][ T8955] Allocated by task 8955: [ 78.005373][ T8955] save_stack+0x23/0x90 [ 78.009527][ T8955] __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 78.015137][ T8955] kasan_slab_alloc+0xf/0x20 [ 78.019728][ T8955] kmem_cache_alloc+0x11a/0x6f0 [ 78.024588][ T8955] alloc_vfsmnt+0x28/0x780 [ 78.028989][ T8955] vfs_create_mount+0x96/0x500 [ 78.033741][ T8955] __ia32_sys_fsmount+0x584/0xc80 [ 78.038745][ T8955] do_fast_syscall_32+0x27b/0xd7d [ 78.043751][ T8955] entry_SYSENTER_compat+0x70/0x7f [ 78.048833][ T8955] [ 78.051139][ T8955] Freed by task 16: [ 78.054930][ T8955] save_stack+0x23/0x90 [ 78.059072][ T8955] __kasan_slab_free+0x102/0x150 [ 78.064004][ T8955] kasan_slab_free+0xe/0x10 [ 78.068484][ T8955] kmem_cache_free+0x86/0x260 [ 78.073144][ T8955] free_vfsmnt+0x6f/0x90 [ 78.077366][ T8955] delayed_free_vfsmnt+0x16/0x20 [ 78.082298][ T8955] rcu_core+0xba5/0x1500 [ 78.086544][ T8955] __do_softirq+0x25c/0x94c [ 78.091020][ T8955] [ 78.093332][ T8955] The buggy address belongs to the object at ffff88808f661000 [ 78.093332][ T8955] which belongs to the cache mnt_cache of size 432 [ 78.107204][ T8955] The buggy address is located 292 bytes inside of [ 78.107204][ T8955] 432-byte region [ffff88808f661000, ffff88808f6611b0) [ 78.120472][ T8955] The buggy address belongs to the page: [ 78.126098][ T8955] page:ffffea00023d9840 refcount:1 mapcount:0 mapping:ffff8880aa594940 index:0x0 [ 78.135210][ T8955] flags: 0x1fffc0000000200(slab) [ 78.140135][ T8955] raw: 01fffc0000000200 ffffea0002a35e08 ffffea00022a3f08 ffff8880aa594940 [ 78.148716][ T8955] raw: 0000000000000000 ffff88808f661000 0000000100000008 0000000000000000 [ 78.157292][ T8955] page dumped because: kasan: bad access detected [ 78.163681][ T8955] [ 78.165990][ T8955] Memory state around the buggy address: [ 78.171598][ T8955] ffff88808f661000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 78.179642][ T8955] ffff88808f661080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 78.187688][ T8955] >ffff88808f661100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 78.195737][ T8955] ^ [ 78.200849][ T8955] ffff88808f661180: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc [ 78.208908][ T8955] ffff88808f661200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb executing program executing program executing program [ 78.216942][ T8955] ================================================================== [ 78.224974][ T8955] Disabling lock debugging due to kernel taint [ 78.233873][ T8955] Kernel panic - not syncing: panic_on_warn set ... [ 78.240476][ T8955] CPU: 1 PID: 8955 Comm: syz-executor817 Tainted: G B 5.2.0-rc4 #18 [ 78.249748][ T8955] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 78.259783][ T8955] Call Trace: [ 78.263067][ T8955] dump_stack+0x172/0x1f0 [ 78.267400][ T8955] panic+0x2cb/0x744 [ 78.271291][ T8955] ? __warn_printk+0xf3/0xf3 [ 78.275862][ T8955] ? mntput+0x91/0xa0 [ 78.279827][ T8955] ? preempt_schedule+0x4b/0x60 [ 78.284659][ T8955] ? ___preempt_schedule+0x16/0x18 [ 78.289943][ T8955] ? trace_hardirqs_on+0x5e/0x220 [ 78.294953][ T8955] ? mntput+0x91/0xa0 [ 78.298919][ T8955] end_report+0x47/0x4f [ 78.303054][ T8955] ? mntput+0x91/0xa0 [ 78.307024][ T8955] __kasan_report.cold+0xe/0x40 [ 78.311884][ T8955] ? mntput+0x91/0xa0 [ 78.315866][ T8955] kasan_report+0x12/0x20 [ 78.320211][ T8955] __asan_report_load4_noabort+0x14/0x20 [ 78.325829][ T8955] mntput+0x91/0xa0 [ 78.329621][ T8955] path_put+0x50/0x70 [ 78.333583][ T8955] free_fs_struct+0x25/0x70 [ 78.338080][ T8955] exit_fs+0xf0/0x130 [ 78.342128][ T8955] do_exit+0x8e0/0x2fa0 [ 78.346283][ T8955] ? __do_page_fault+0x623/0xda0 [ 78.351203][ T8955] ? mm_update_next_owner+0x640/0x640 [ 78.356555][ T8955] ? kasan_check_read+0x11/0x20 [ 78.361411][ T8955] ? kasan_check_write+0x14/0x20 [ 78.366350][ T8955] ? up_read+0xc4/0x200 [ 78.370501][ T8955] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 78.375940][ T8955] do_group_exit+0x135/0x370 [ 78.380512][ T8955] __ia32_sys_exit_group+0x44/0x50 [ 78.385604][ T8955] do_fast_syscall_32+0x27b/0xd7d [ 78.390620][ T8955] entry_SYSENTER_compat+0x70/0x7f [ 78.395709][ T8955] RIP: 0023:0xf7f16849 [ 78.399758][ T8955] Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 [ 78.419338][ T8955] RSP: 002b:00000000ffe4f85c EFLAGS: 00000296 ORIG_RAX: 00000000000000fc [ 78.427727][ T8955] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000080ed2b8 [ 78.435682][ T8955] RDX: 0000000000000000 RSI: 00000000080d71fc RDI: 00000000080ed2c0 [ 78.443638][ T8955] RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 [ 78.451586][ T8955] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 78.459534][ T8955] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 78.468626][ T8955] Kernel Offset: disabled [ 78.472947][ T8955] Rebooting in 86400 seconds..