Starting mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [ 38.881370] audit: type=1800 audit(1569645883.280:33): pid=7353 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 [ 38.904233] audit: type=1800 audit(1569645883.280:34): pid=7353 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="rmnologin" dev="sda1" ino=2456 res=0 Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 41.027175] audit: type=1400 audit(1569645885.430:35): avc: denied { map } for pid=7527 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 '10.128.1.40' (ECDSA) to the list of known hosts. executing program [ 47.497929] audit: type=1400 audit(1569645891.900:36): avc: denied { map } for pid=7539 comm="syz-executor576" path="/root/syz-executor576143063" dev="sda1" ino=16484 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 47.538668] ================================================================== [ 47.546133] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 47.553130] Read of size 4 at addr ffff88808bde076c by task sshd/7537 [ 47.559684] [ 47.561297] CPU: 0 PID: 7537 Comm: sshd Not tainted 4.19.75 #0 [ 47.567245] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.576580] Call Trace: [ 47.579165] dump_stack+0x172/0x1f0 [ 47.582777] ? wait_consider_task+0x1b51/0x3910 [ 47.587431] print_address_description.cold+0x7c/0x20d [ 47.592699] ? wait_consider_task+0x1b51/0x3910 [ 47.597357] kasan_report.cold+0x8c/0x2ba [ 47.601509] __asan_report_load4_noabort+0x14/0x20 [ 47.606428] wait_consider_task+0x1b51/0x3910 [ 47.610916] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 47.616002] ? add_wait_queue+0x112/0x170 [ 47.620139] ? release_task+0x1630/0x1630 [ 47.625320] ? lock_acquire+0x16f/0x3f0 [ 47.629281] ? do_wait+0x3aa/0x9d0 [ 47.632807] ? kasan_check_write+0x14/0x20 [ 47.637026] do_wait+0x439/0x9d0 [ 47.640379] ? wait_consider_task+0x3910/0x3910 [ 47.645028] ? mark_held_locks+0x100/0x100 [ 47.649249] kernel_wait4+0x171/0x290 [ 47.653033] ? __ia32_sys_waitid+0x140/0x140 [ 47.657431] ? task_stopped_code+0x180/0x180 [ 47.661831] __do_sys_wait4+0x147/0x160 [ 47.665791] ? kernel_wait4+0x290/0x290 [ 47.669755] ? kasan_check_read+0x11/0x20 [ 47.673917] ? _copy_to_user+0xc9/0x120 [ 47.677890] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 47.683437] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 47.688444] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.693185] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.697927] ? do_syscall_64+0x26/0x620 [ 47.701908] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.707256] ? do_syscall_64+0x26/0x620 [ 47.711217] __x64_sys_wait4+0x97/0xf0 [ 47.715128] do_syscall_64+0xfd/0x620 [ 47.718914] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.724129] RIP: 0033:0x7f26d673fa3e [ 47.727851] 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 [ 47.746735] RSP: 002b:00007ffd544b7b30 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 47.754426] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f26d673fa3e [ 47.761679] RDX: 0000000000000001 RSI: 00007ffd544b7b6c RDI: ffffffffffffffff [ 47.768933] RBP: 000055c04d9fac88 R08: 00007ffd544b7c30 R09: 0101010101010101 [ 47.776183] R10: 0000000000000000 R11: 0000000000000246 R12: 000055c04e233c00 [ 47.783436] R13: 000055c04d9f8fb4 R14: 0000000000000028 R15: 000055c04d9faca0 [ 47.790706] [ 47.792315] Allocated by task 7537: [ 47.795930] save_stack+0x45/0xd0 [ 47.799363] kasan_kmalloc+0xce/0xf0 [ 47.803056] kasan_slab_alloc+0xf/0x20 [ 47.806925] kmem_cache_alloc_node+0x144/0x710 [ 47.811500] copy_process.part.0+0x1ce0/0x7a30 [ 47.816078] _do_fork+0x257/0xfd0 [ 47.819512] __x64_sys_clone+0xbf/0x150 [ 47.823469] do_syscall_64+0xfd/0x620 [ 47.827271] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 47.832436] [ 47.834047] Freed by task 0: [ 47.837122] save_stack+0x45/0xd0 [ 47.840560] __kasan_slab_free+0x102/0x150 [ 47.844859] kasan_slab_free+0xe/0x10 [ 47.848676] kmem_cache_free+0x86/0x260 [ 47.852785] free_task+0xdd/0x120 [ 47.856229] __put_task_struct+0x20f/0x4c0 [ 47.860471] finish_task_switch+0x52b/0x780 [ 47.864778] __schedule+0x86e/0x1dc0 [ 47.868490] schedule_idle+0x58/0x80 [ 47.872198] do_idle+0x192/0x560 [ 47.875643] cpu_startup_entry+0xc8/0xe0 [ 47.879687] start_secondary+0x3e8/0x5b0 [ 47.883731] secondary_startup_64+0xa4/0xb0 [ 47.888028] [ 47.889641] The buggy address belongs to the object at ffff88808bde0300 [ 47.889641] which belongs to the cache task_struct of size 6080 [ 47.902367] The buggy address is located 1132 bytes inside of [ 47.902367] 6080-byte region [ffff88808bde0300, ffff88808bde1ac0) [ 47.914484] The buggy address belongs to the page: [ 47.919396] page:ffffea00022f7800 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 47.929347] flags: 0x1fffc0000008100(slab|head) [ 47.933999] raw: 01fffc0000008100 ffffea000234f388 ffffea00029e9208 ffff88812c26d800 [ 47.941864] raw: 0000000000000000 ffff88808bde0300 0000000100000001 0000000000000000 [ 47.949724] page dumped because: kasan: bad access detected [ 47.955423] [ 47.957030] Memory state around the buggy address: [ 47.961943] ffff88808bde0600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.969296] ffff88808bde0680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.976640] >ffff88808bde0700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.983977] ^ [ 47.990724] ffff88808bde0780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 47.998072] ffff88808bde0800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 48.005408] ================================================================== [ 48.012746] Disabling lock debugging due to kernel taint [ 48.018366] Kernel panic - not syncing: panic_on_warn set ... [ 48.018366] [ 48.025739] CPU: 0 PID: 7537 Comm: sshd Tainted: G B 4.19.75 #0 [ 48.033084] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 48.042425] Call Trace: [ 48.045000] dump_stack+0x172/0x1f0 [ 48.048611] ? wait_consider_task+0x1b51/0x3910 [ 48.053258] panic+0x263/0x507 [ 48.056432] ? __warn_printk+0xf3/0xf3 [ 48.060298] ? retint_kernel+0x2d/0x2d [ 48.064171] ? trace_hardirqs_on+0x5e/0x220 [ 48.068476] ? wait_consider_task+0x1b51/0x3910 [ 48.073140] kasan_end_report+0x47/0x4f [ 48.077097] kasan_report.cold+0xa9/0x2ba [ 48.081229] __asan_report_load4_noabort+0x14/0x20 [ 48.086140] wait_consider_task+0x1b51/0x3910 [ 48.090630] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 48.095713] ? add_wait_queue+0x112/0x170 [ 48.099846] ? release_task+0x1630/0x1630 [ 48.103971] ? lock_acquire+0x16f/0x3f0 [ 48.107936] ? do_wait+0x3aa/0x9d0 [ 48.111475] ? kasan_check_write+0x14/0x20 [ 48.115692] do_wait+0x439/0x9d0 [ 48.119043] ? wait_consider_task+0x3910/0x3910 [ 48.123698] ? mark_held_locks+0x100/0x100 [ 48.127918] kernel_wait4+0x171/0x290 [ 48.131702] ? __ia32_sys_waitid+0x140/0x140 [ 48.136093] ? task_stopped_code+0x180/0x180 [ 48.140487] __do_sys_wait4+0x147/0x160 [ 48.144454] ? kernel_wait4+0x290/0x290 [ 48.148412] ? kasan_check_read+0x11/0x20 [ 48.152544] ? _copy_to_user+0xc9/0x120 [ 48.156520] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 48.162078] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 48.167096] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.171837] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.176573] ? do_syscall_64+0x26/0x620 [ 48.180552] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.185907] ? do_syscall_64+0x26/0x620 [ 48.189863] __x64_sys_wait4+0x97/0xf0 [ 48.193734] do_syscall_64+0xfd/0x620 [ 48.197519] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 48.202692] RIP: 0033:0x7f26d673fa3e [ 48.206390] 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 [ 48.225275] RSP: 002b:00007ffd544b7b30 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 48.232966] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f26d673fa3e [ 48.240225] RDX: 0000000000000001 RSI: 00007ffd544b7b6c RDI: ffffffffffffffff [ 48.247475] RBP: 000055c04d9fac88 R08: 00007ffd544b7c30 R09: 0101010101010101 [ 48.254724] R10: 0000000000000000 R11: 0000000000000246 R12: 000055c04e233c00 [ 48.261975] R13: 000055c04d9f8fb4 R14: 0000000000000028 R15: 000055c04d9faca0 [ 48.270770] Kernel Offset: disabled [ 48.274395] Rebooting in 86400 seconds..