[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 75.751954][ T26] audit: type=1800 audit(1585019505.945:25): pid=9571 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 75.772112][ T26] audit: type=1800 audit(1585019505.955:26): pid=9571 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 75.814141][ T26] audit: type=1800 audit(1585019505.955:27): pid=9571 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 '10.128.1.45' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program syzkaller login: [ 84.756810][ T9725] ================================================================== [ 84.765118][ T9725] BUG: KASAN: use-after-free in try_to_grab_pending+0x112/0x8e0 [ 84.772792][ T9725] Write of size 8 at addr ffff8880a9367008 by task syz-executor670/9725 [ 84.781145][ T9725] [ 84.783486][ T9725] CPU: 1 PID: 9725 Comm: syz-executor670 Not tainted 5.6.0-rc7-syzkaller #0 [ 84.792163][ T9725] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 84.802229][ T9725] Call Trace: [ 84.805561][ T9725] dump_stack+0x188/0x20d [ 84.809908][ T9725] ? try_to_grab_pending+0x112/0x8e0 [ 84.815216][ T9725] ? try_to_grab_pending+0x112/0x8e0 [ 84.820521][ T9725] print_address_description.constprop.0.cold+0xd3/0x315 [ 84.827564][ T9725] ? try_to_grab_pending+0x112/0x8e0 [ 84.832871][ T9725] ? try_to_grab_pending+0x112/0x8e0 [ 84.838168][ T9725] __kasan_report.cold+0x1a/0x32 [ 84.843123][ T9725] ? firmware_map_remove+0xe3/0x19a [ 84.848332][ T9725] ? try_to_grab_pending+0x112/0x8e0 [ 84.853665][ T9725] kasan_report+0xe/0x20 [ 84.857902][ T9725] check_memory_region+0x128/0x190 [ 84.863022][ T9725] try_to_grab_pending+0x112/0x8e0 [ 84.868147][ T9725] __cancel_work_timer+0xa6/0x500 [ 84.873177][ T9725] ? mod_delayed_work_on+0x1f0/0x1f0 [ 84.878465][ T9725] ? console_unlock+0x7a6/0xf00 [ 84.883320][ T9725] ? lockdep_hardirqs_on+0x417/0x5d0 [ 84.888648][ T9725] ? get_work_pool+0x1a0/0x1a0 [ 84.893409][ T9725] release_tty+0x253/0x450 [ 84.897838][ T9725] tty_release_struct+0x37/0x50 [ 84.902681][ T9725] tty_release+0xbc7/0xe90 [ 84.907112][ T9725] ? do_tty_hangup+0x30/0x30 [ 84.911690][ T9725] __fput+0x2da/0x850 [ 84.915664][ T9725] task_work_run+0x13f/0x1b0 [ 84.920256][ T9725] do_exit+0xb34/0x2dd0 [ 84.924470][ T9725] ? mm_update_next_owner+0x7a0/0x7a0 [ 84.929827][ T9725] ? up_read+0x1ab/0x750 [ 84.934063][ T9725] ? mark_held_locks+0x9f/0xe0 [ 84.938857][ T9725] ? down_read_non_owner+0x470/0x470 [ 84.944145][ T9725] ? handle_mm_fault+0x491/0xa10 [ 84.949081][ T9725] do_group_exit+0x125/0x340 [ 84.953661][ T9725] __x64_sys_exit_group+0x3a/0x50 [ 84.958683][ T9725] do_syscall_64+0xf6/0x7d0 [ 84.963192][ T9725] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 84.969069][ T9725] RIP: 0033:0x43ff38 [ 84.972954][ T9725] 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 [ 84.992589][ T9725] RSP: 002b:00007fff43c88d28 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 85.001007][ T9725] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 85.009002][ T9725] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 85.017007][ T9725] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 85.024966][ T9725] R10: 0000000000000064 R11: 0000000000000246 R12: 0000000000000001 [ 85.032921][ T9725] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 85.040889][ T9725] [ 85.043207][ T9725] Allocated by task 9725: [ 85.047536][ T9725] save_stack+0x1b/0x80 [ 85.051673][ T9725] __kasan_kmalloc.constprop.0+0xbf/0xd0 [ 85.057307][ T9725] kmem_cache_alloc_trace+0x153/0x7d0 [ 85.062672][ T9725] vc_allocate+0x1e2/0x6e0 [ 85.067081][ T9725] con_install+0x4f/0x400 [ 85.071408][ T9725] tty_init_dev+0xf5/0x460 [ 85.075809][ T9725] tty_open+0x47f/0xb30 [ 85.079965][ T9725] chrdev_open+0x219/0x5c0 [ 85.084535][ T9725] do_dentry_open+0x4a2/0x1250 [ 85.089296][ T9725] path_openat+0x122a/0x32b0 [ 85.093890][ T9725] do_filp_open+0x192/0x260 [ 85.098399][ T9725] do_sys_openat2+0x54c/0x740 [ 85.103121][ T9725] do_sys_open+0xc3/0x140 [ 85.107464][ T9725] do_syscall_64+0xf6/0x7d0 [ 85.111991][ T9725] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 85.117858][ T9725] [ 85.120185][ T9725] Freed by task 9732: [ 85.124174][ T9725] save_stack+0x1b/0x80 [ 85.128339][ T9725] __kasan_slab_free+0xf7/0x140 [ 85.133171][ T9725] kfree+0x109/0x2b0 [ 85.137070][ T9725] vt_disallocate_all+0x293/0x3b0 [ 85.142081][ T9725] vt_ioctl+0xb79/0x2470 [ 85.146308][ T9725] tty_ioctl+0xedd/0x1440 [ 85.150637][ T9725] ksys_ioctl+0x11a/0x180 [ 85.154968][ T9725] __x64_sys_ioctl+0x6f/0xb0 [ 85.159581][ T9725] do_syscall_64+0xf6/0x7d0 [ 85.164109][ T9725] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 85.169996][ T9725] [ 85.172330][ T9725] The buggy address belongs to the object at ffff8880a9367000 [ 85.172330][ T9725] which belongs to the cache kmalloc-2k of size 2048 [ 85.186383][ T9725] The buggy address is located 8 bytes inside of [ 85.186383][ T9725] 2048-byte region [ffff8880a9367000, ffff8880a9367800) [ 85.199684][ T9725] The buggy address belongs to the page: [ 85.205309][ T9725] page:ffffea0002a4d9c0 refcount:1 mapcount:0 mapping:ffff8880aa000e00 index:0x0 [ 85.214423][ T9725] flags: 0xfffe0000000200(slab) [ 85.219273][ T9725] raw: 00fffe0000000200 ffffea00022bb448 ffffea00029f34c8 ffff8880aa000e00 [ 85.227857][ T9725] raw: 0000000000000000 ffff8880a9367000 0000000100000001 0000000000000000 [ 85.236442][ T9725] page dumped because: kasan: bad access detected [ 85.243456][ T9725] [ 85.245773][ T9725] Memory state around the buggy address: [ 85.251388][ T9725] ffff8880a9366f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 85.259448][ T9725] ffff8880a9366f80: fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 85.267514][ T9725] >ffff8880a9367000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 85.275576][ T9725] ^ [ 85.279896][ T9725] ffff8880a9367080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 85.287954][ T9725] ffff8880a9367100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 85.296002][ T9725] ================================================================== [ 85.304450][ T9725] Disabling lock debugging due to kernel taint [ 85.310654][ T9725] Kernel panic - not syncing: panic_on_warn set ... [ 85.317282][ T9725] CPU: 1 PID: 9725 Comm: syz-executor670 Tainted: G B 5.6.0-rc7-syzkaller #0 [ 85.327449][ T9725] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 85.337524][ T9725] Call Trace: [ 85.340861][ T9725] dump_stack+0x188/0x20d [ 85.345244][ T9725] panic+0x2e3/0x75c [ 85.349129][ T9725] ? add_taint.cold+0x16/0x16 [ 85.353801][ T9725] ? print_shadow_for_address+0xb8/0x114 [ 85.359426][ T9725] ? trace_hardirqs_off+0x50/0x220 [ 85.364541][ T9725] ? try_to_grab_pending+0x112/0x8e0 [ 85.369823][ T9725] end_report+0x43/0x49 [ 85.374083][ T9725] ? try_to_grab_pending+0x112/0x8e0 [ 85.379394][ T9725] __kasan_report.cold+0xd/0x32 [ 85.384245][ T9725] ? firmware_map_remove+0xe3/0x19a [ 85.389440][ T9725] ? try_to_grab_pending+0x112/0x8e0 [ 85.394761][ T9725] kasan_report+0xe/0x20 [ 85.399043][ T9725] check_memory_region+0x128/0x190 [ 85.404153][ T9725] try_to_grab_pending+0x112/0x8e0 [ 85.409310][ T9725] __cancel_work_timer+0xa6/0x500 [ 85.414327][ T9725] ? mod_delayed_work_on+0x1f0/0x1f0 [ 85.419642][ T9725] ? console_unlock+0x7a6/0xf00 [ 85.424478][ T9725] ? lockdep_hardirqs_on+0x417/0x5d0 [ 85.429789][ T9725] ? get_work_pool+0x1a0/0x1a0 [ 85.434562][ T9725] release_tty+0x253/0x450 [ 85.438979][ T9725] tty_release_struct+0x37/0x50 [ 85.443836][ T9725] tty_release+0xbc7/0xe90 [ 85.448245][ T9725] ? do_tty_hangup+0x30/0x30 [ 85.452874][ T9725] __fput+0x2da/0x850 [ 85.456855][ T9725] task_work_run+0x13f/0x1b0 [ 85.461460][ T9725] do_exit+0xb34/0x2dd0 [ 85.465623][ T9725] ? mm_update_next_owner+0x7a0/0x7a0 [ 85.471028][ T9725] ? up_read+0x1ab/0x750 [ 85.475296][ T9725] ? mark_held_locks+0x9f/0xe0 [ 85.480085][ T9725] ? down_read_non_owner+0x470/0x470 [ 85.485400][ T9725] ? handle_mm_fault+0x491/0xa10 [ 85.490348][ T9725] do_group_exit+0x125/0x340 [ 85.494929][ T9725] __x64_sys_exit_group+0x3a/0x50 [ 85.499947][ T9725] do_syscall_64+0xf6/0x7d0 [ 85.504480][ T9725] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 85.510372][ T9725] RIP: 0033:0x43ff38 [ 85.514250][ T9725] 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 [ 85.533887][ T9725] RSP: 002b:00007fff43c88d28 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 85.542372][ T9725] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38 [ 85.550359][ T9725] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 85.558357][ T9725] RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 85.566351][ T9725] R10: 0000000000000064 R11: 0000000000000246 R12: 0000000000000001 [ 85.574313][ T9725] R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000 [ 85.583420][ T9725] Kernel Offset: disabled [ 85.587745][ T9725] Rebooting in 86400 seconds..