[ 37.290341] audit: type=1800 audit(1569563607.044:32): pid=7382 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="ssh" dev="sda1" ino=2450 res=0 Starting mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[[ 38.046898] audit: type=1800 audit(1569563607.884:33): pid=7382 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="rc.local" dev="sda1" ino=2465 res=0 1G[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.1.55' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 45.724682] kauditd_printk_skb: 2 callbacks suppressed [ 45.724696] audit: type=1400 audit(1569563615.564:36): avc: denied { map } for pid=7569 comm="syz-executor319" path="/root/syz-executor319150979" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 45.758956] ================================================================== [ 45.766412] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 45.773416] Read of size 4 at addr ffff88809adac7ec by task sshd/7567 [ 45.779972] [ 45.781587] CPU: 1 PID: 7567 Comm: sshd Not tainted 4.19.75 #0 [ 45.787548] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.796885] Call Trace: [ 45.799473] dump_stack+0x172/0x1f0 [ 45.803100] ? wait_consider_task+0x1b51/0x3910 [ 45.807754] print_address_description.cold+0x7c/0x20d [ 45.813029] ? wait_consider_task+0x1b51/0x3910 [ 45.817681] kasan_report.cold+0x8c/0x2ba [ 45.821814] __asan_report_load4_noabort+0x14/0x20 [ 45.826727] wait_consider_task+0x1b51/0x3910 [ 45.831211] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 45.836314] ? add_wait_queue+0x112/0x170 [ 45.840445] ? release_task+0x1630/0x1630 [ 45.844592] ? lock_acquire+0x16f/0x3f0 [ 45.848549] ? do_wait+0x3aa/0x9d0 [ 45.852084] ? kasan_check_write+0x14/0x20 [ 45.856305] do_wait+0x439/0x9d0 [ 45.859670] ? wait_consider_task+0x3910/0x3910 [ 45.864335] ? mark_held_locks+0x100/0x100 [ 45.868568] kernel_wait4+0x171/0x290 [ 45.872356] ? __ia32_sys_waitid+0x140/0x140 [ 45.876751] ? task_stopped_code+0x180/0x180 [ 45.881148] __do_sys_wait4+0x147/0x160 [ 45.885109] ? kernel_wait4+0x290/0x290 [ 45.889070] ? kasan_check_read+0x11/0x20 [ 45.893224] ? _copy_to_user+0xc9/0x120 [ 45.897358] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 45.902900] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 45.907925] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 45.912678] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 45.917427] ? do_syscall_64+0x26/0x620 [ 45.921420] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 45.926770] ? do_syscall_64+0x26/0x620 [ 45.930735] __x64_sys_wait4+0x97/0xf0 [ 45.934610] do_syscall_64+0xfd/0x620 [ 45.938400] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 45.943596] RIP: 0033:0x7fcaa798ea3e [ 45.947301] Code: 90 90 90 90 90 90 90 90 90 90 90 90 48 83 ec 28 8b 05 c2 eb 2d 00 85 c0 75 1d 45 31 d2 48 63 d2 48 63 ff b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 55 48 83 c4 28 c3 89 54 24 08 48 89 74 24 10 [ 45.966207] RSP: 002b:00007ffc9f85fc90 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 45.973913] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcaa798ea3e [ 45.981183] RDX: 0000000000000001 RSI: 00007ffc9f85fccc RDI: ffffffffffffffff [ 45.988451] RBP: 0000559147368c88 R08: 00007ffc9f85fd90 R09: 0101010101010101 [ 45.995748] R10: 0000000000000000 R11: 0000000000000246 R12: 0000559147b6bc00 [ 46.003019] R13: 0000559147366fb4 R14: 0000000000000028 R15: 0000559147368ca0 [ 46.010297] [ 46.011913] Allocated by task 7567: [ 46.015550] save_stack+0x45/0xd0 [ 46.018999] kasan_kmalloc+0xce/0xf0 [ 46.022697] kasan_slab_alloc+0xf/0x20 [ 46.026566] kmem_cache_alloc_node+0x144/0x710 [ 46.031144] copy_process.part.0+0x1ce0/0x7a30 [ 46.035712] _do_fork+0x257/0xfd0 [ 46.039150] __x64_sys_clone+0xbf/0x150 [ 46.043133] do_syscall_64+0xfd/0x620 [ 46.046918] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 46.052106] [ 46.053720] Freed by task 0: [ 46.056723] save_stack+0x45/0xd0 [ 46.060248] __kasan_slab_free+0x102/0x150 [ 46.064478] kasan_slab_free+0xe/0x10 [ 46.068260] kmem_cache_free+0x86/0x260 [ 46.072227] free_task+0xdd/0x120 [ 46.075667] __put_task_struct+0x20f/0x4c0 [ 46.079898] finish_task_switch+0x52b/0x780 [ 46.084206] __schedule+0x86e/0x1dc0 [ 46.087902] schedule_idle+0x58/0x80 [ 46.091596] do_idle+0x192/0x560 [ 46.094943] cpu_startup_entry+0xc8/0xe0 [ 46.098991] rest_init+0x219/0x222 [ 46.102516] start_kernel+0x88c/0x8c5 [ 46.106298] x86_64_start_reservations+0x29/0x2b [ 46.111035] x86_64_start_kernel+0x77/0x7b [ 46.115253] secondary_startup_64+0xa4/0xb0 [ 46.119551] [ 46.121161] The buggy address belongs to the object at ffff88809adac380 [ 46.121161] which belongs to the cache task_struct of size 6080 [ 46.133887] The buggy address is located 1132 bytes inside of [ 46.133887] 6080-byte region [ffff88809adac380, ffff88809adadb40) [ 46.145914] The buggy address belongs to the page: [ 46.150826] page:ffffea00026b6b00 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 46.160780] flags: 0x1fffc0000008100(slab|head) [ 46.165438] raw: 01fffc0000008100 ffffea0002601a08 ffffea000200b508 ffff88812c26d800 [ 46.173305] raw: 0000000000000000 ffff88809adac380 0000000100000001 0000000000000000 [ 46.181164] page dumped because: kasan: bad access detected [ 46.186852] [ 46.188460] Memory state around the buggy address: [ 46.193371] ffff88809adac680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 46.200760] ffff88809adac700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 46.208102] >ffff88809adac780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 46.215443] ^ [ 46.222178] ffff88809adac800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 46.230387] ffff88809adac880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 46.237725] ================================================================== [ 46.245063] Disabling lock debugging due to kernel taint [ 46.250721] Kernel panic - not syncing: panic_on_warn set ... [ 46.250721] [ 46.258093] CPU: 1 PID: 7567 Comm: sshd Tainted: G B 4.19.75 #0 [ 46.265456] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 46.274889] Call Trace: [ 46.277463] dump_stack+0x172/0x1f0 [ 46.281076] ? wait_consider_task+0x1b51/0x3910 [ 46.285726] panic+0x263/0x507 [ 46.288899] ? __warn_printk+0xf3/0xf3 [ 46.292770] ? retint_kernel+0x2d/0x2d [ 46.296641] ? trace_hardirqs_on+0x5e/0x220 [ 46.300946] ? wait_consider_task+0x1b51/0x3910 [ 46.305599] kasan_end_report+0x47/0x4f [ 46.309648] kasan_report.cold+0xa9/0x2ba [ 46.313779] __asan_report_load4_noabort+0x14/0x20 [ 46.318693] wait_consider_task+0x1b51/0x3910 [ 46.323172] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 46.328257] ? add_wait_queue+0x112/0x170 [ 46.332387] ? release_task+0x1630/0x1630 [ 46.336518] ? lock_acquire+0x16f/0x3f0 [ 46.340473] ? do_wait+0x3aa/0x9d0 [ 46.343999] ? kasan_check_write+0x14/0x20 [ 46.348216] do_wait+0x439/0x9d0 [ 46.351564] ? wait_consider_task+0x3910/0x3910 [ 46.356215] ? mark_held_locks+0x100/0x100 [ 46.360443] kernel_wait4+0x171/0x290 [ 46.364227] ? __ia32_sys_waitid+0x140/0x140 [ 46.368620] ? task_stopped_code+0x180/0x180 [ 46.373014] __do_sys_wait4+0x147/0x160 [ 46.376970] ? kernel_wait4+0x290/0x290 [ 46.380933] ? kasan_check_read+0x11/0x20 [ 46.385069] ? _copy_to_user+0xc9/0x120 [ 46.389026] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 46.394567] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 46.399573] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 46.404667] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 46.409413] ? do_syscall_64+0x26/0x620 [ 46.413377] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 46.418723] ? do_syscall_64+0x26/0x620 [ 46.422684] __x64_sys_wait4+0x97/0xf0 [ 46.426555] do_syscall_64+0xfd/0x620 [ 46.430342] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 46.435513] RIP: 0033:0x7fcaa798ea3e [ 46.439207] Code: 90 90 90 90 90 90 90 90 90 90 90 90 48 83 ec 28 8b 05 c2 eb 2d 00 85 c0 75 1d 45 31 d2 48 63 d2 48 63 ff b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 55 48 83 c4 28 c3 89 54 24 08 48 89 74 24 10 [ 46.458093] RSP: 002b:00007ffc9f85fc90 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 46.465786] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcaa798ea3e [ 46.473035] RDX: 0000000000000001 RSI: 00007ffc9f85fccc RDI: ffffffffffffffff [ 46.480286] RBP: 0000559147368c88 R08: 00007ffc9f85fd90 R09: 0101010101010101 [ 46.487551] R10: 0000000000000000 R11: 0000000000000246 R12: 0000559147b6bc00 [ 46.494814] R13: 0000559147366fb4 R14: 0000000000000028 R15: 0000559147368ca0 [ 46.503677] Kernel Offset: disabled [ 46.507302] Rebooting in 86400 seconds..