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[ 38.247179] audit: type=1800 audit(1569059354.185:33): pid=7340 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 [?25l[?1c7[ ok [39;[ 38.272115] audit: type=1800 audit(1569059354.185:34): pid=7340 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 49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 43.754182] audit: type=1400 audit(1569059359.695:35): avc: denied { map } for pid=7515 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 '10.128.0.90' (ECDSA) to the list of known hosts. executing program [ 50.320916] audit: type=1400 audit(1569059366.255:36): avc: denied { map } for pid=7527 comm="syz-executor068" path="/root/syz-executor068688240" 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 [ 50.354585] ================================================================== [ 50.364119] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 50.372705] Read of size 4 at addr ffff888084dd876c by task sshd/7525 [ 50.381246] [ 50.383566] CPU: 0 PID: 7525 Comm: sshd Not tainted 4.19.75 #0 [ 50.392554] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 50.405013] Call Trace: [ 50.407978] dump_stack+0x172/0x1f0 [ 50.411879] ? wait_consider_task+0x1b51/0x3910 [ 50.418119] print_address_description.cold+0x7c/0x20d [ 50.424350] ? wait_consider_task+0x1b51/0x3910 [ 50.429478] kasan_report.cold+0x8c/0x2ba [ 50.435280] __asan_report_load4_noabort+0x14/0x20 [ 50.440791] wait_consider_task+0x1b51/0x3910 [ 50.446455] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 50.452414] ? add_wait_queue+0x112/0x170 [ 50.456758] ? release_task+0x1630/0x1630 [ 50.461622] ? lock_acquire+0x16f/0x3f0 [ 50.465781] ? do_wait+0x3aa/0x9d0 [ 50.469998] ? kasan_check_write+0x14/0x20 [ 50.474528] do_wait+0x439/0x9d0 [ 50.478412] ? wait_consider_task+0x3910/0x3910 [ 50.484064] ? mark_held_locks+0x100/0x100 [ 50.488933] kernel_wait4+0x171/0x290 [ 50.493426] ? __ia32_sys_waitid+0x140/0x140 [ 50.498052] ? task_stopped_code+0x180/0x180 [ 50.502779] __do_sys_wait4+0x147/0x160 [ 50.507161] ? kernel_wait4+0x290/0x290 [ 50.511960] ? kasan_check_read+0x11/0x20 [ 50.517322] ? _copy_to_user+0xc9/0x120 [ 50.522124] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 50.529984] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 50.535278] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 50.540429] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 50.545904] ? do_syscall_64+0x26/0x620 [ 50.550232] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.556295] ? do_syscall_64+0x26/0x620 [ 50.561637] __x64_sys_wait4+0x97/0xf0 [ 50.565877] do_syscall_64+0xfd/0x620 [ 50.570141] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.576263] RIP: 0033:0x7fef9662ea3e [ 50.580671] 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 [ 50.602028] RSP: 002b:00007ffec58c46a0 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 50.610551] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fef9662ea3e [ 50.618637] RDX: 0000000000000001 RSI: 00007ffec58c46dc RDI: ffffffffffffffff [ 50.626974] RBP: 00005601c91e6c88 R08: 00007ffec58c47a0 R09: 0101010101010101 [ 50.636068] R10: 0000000000000000 R11: 0000000000000246 R12: 00005601caae7af0 [ 50.644608] R13: 00005601c91e4fb4 R14: 0000000000000028 R15: 00005601c91e6ca0 [ 50.652126] [ 50.654090] Allocated by task 7525: [ 50.658157] save_stack+0x45/0xd0 [ 50.662083] kasan_kmalloc+0xce/0xf0 [ 50.666445] kasan_slab_alloc+0xf/0x20 [ 50.670348] kmem_cache_alloc_node+0x144/0x710 [ 50.675147] copy_process.part.0+0x1ce0/0x7a30 [ 50.681027] _do_fork+0x257/0xfd0 [ 50.684971] __x64_sys_clone+0xbf/0x150 [ 50.689442] do_syscall_64+0xfd/0x620 [ 50.694374] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.700731] [ 50.702549] Freed by task 0: [ 50.705707] save_stack+0x45/0xd0 [ 50.710148] __kasan_slab_free+0x102/0x150 [ 50.715689] kasan_slab_free+0xe/0x10 [ 50.720081] kmem_cache_free+0x86/0x260 [ 50.724794] free_task+0xdd/0x120 [ 50.729251] __put_task_struct+0x20f/0x4c0 [ 50.734085] finish_task_switch+0x52b/0x780 [ 50.738750] __schedule+0x86e/0x1dc0 [ 50.743624] schedule_idle+0x58/0x80 [ 50.748888] do_idle+0x192/0x560 [ 50.753111] cpu_startup_entry+0xc8/0xe0 [ 50.758831] start_secondary+0x3e8/0x5b0 [ 50.763519] secondary_startup_64+0xa4/0xb0 [ 50.768215] [ 50.769994] The buggy address belongs to the object at ffff888084dd8300 [ 50.769994] which belongs to the cache task_struct of size 6080 [ 50.787142] The buggy address is located 1132 bytes inside of [ 50.787142] 6080-byte region [ffff888084dd8300, ffff888084dd9ac0) [ 50.802019] The buggy address belongs to the page: [ 50.807533] page:ffffea0002137600 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 50.818748] flags: 0x1fffc0000008100(slab|head) [ 50.823669] raw: 01fffc0000008100 ffffea00022e9c08 ffffea00025c2208 ffff88812c26d800 [ 50.832670] raw: 0000000000000000 ffff888084dd8300 0000000100000001 0000000000000000 [ 50.841607] page dumped because: kasan: bad access detected [ 50.847943] [ 50.849568] Memory state around the buggy address: [ 50.855027] ffff888084dd8600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.863686] ffff888084dd8680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.873050] >ffff888084dd8700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.881855] ^ [ 50.889108] ffff888084dd8780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.897018] ffff888084dd8800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 50.905644] ================================================================== [ 50.915000] Disabling lock debugging due to kernel taint [ 50.921414] Kernel panic - not syncing: panic_on_warn set ... [ 50.921414] [ 50.929266] CPU: 0 PID: 7525 Comm: sshd Tainted: G B 4.19.75 #0 [ 50.938051] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 50.948365] Call Trace: [ 50.951517] dump_stack+0x172/0x1f0 [ 50.955663] ? wait_consider_task+0x1b51/0x3910 [ 50.960668] panic+0x263/0x507 [ 50.964036] ? __warn_printk+0xf3/0xf3 [ 50.968270] ? retint_kernel+0x2d/0x2d [ 50.972247] ? trace_hardirqs_on+0x5e/0x220 [ 50.977560] ? wait_consider_task+0x1b51/0x3910 [ 50.982417] kasan_end_report+0x47/0x4f [ 50.986964] kasan_report.cold+0xa9/0x2ba [ 50.991496] __asan_report_load4_noabort+0x14/0x20 [ 50.997366] wait_consider_task+0x1b51/0x3910 [ 51.004826] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 51.011084] ? add_wait_queue+0x112/0x170 [ 51.015973] ? release_task+0x1630/0x1630 [ 51.021102] ? lock_acquire+0x16f/0x3f0 [ 51.025330] ? do_wait+0x3aa/0x9d0 [ 51.029140] ? kasan_check_write+0x14/0x20 [ 51.033701] do_wait+0x439/0x9d0 [ 51.037644] ? wait_consider_task+0x3910/0x3910 [ 51.043856] ? mark_held_locks+0x100/0x100 [ 51.049123] kernel_wait4+0x171/0x290 [ 51.053560] ? __ia32_sys_waitid+0x140/0x140 [ 51.059607] ? task_stopped_code+0x180/0x180 [ 51.064600] __do_sys_wait4+0x147/0x160 [ 51.069224] ? kernel_wait4+0x290/0x290 [ 51.073578] ? kasan_check_read+0x11/0x20 [ 51.077828] ? _copy_to_user+0xc9/0x120 [ 51.082034] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 51.088309] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 51.094429] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 51.099498] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 51.105041] ? do_syscall_64+0x26/0x620 [ 51.109550] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.115330] ? do_syscall_64+0x26/0x620 [ 51.119596] __x64_sys_wait4+0x97/0xf0 [ 51.124102] do_syscall_64+0xfd/0x620 [ 51.128272] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.134629] RIP: 0033:0x7fef9662ea3e [ 51.138696] 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 [ 51.162565] RSP: 002b:00007ffec58c46a0 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 51.170708] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fef9662ea3e [ 51.182026] RDX: 0000000000000001 RSI: 00007ffec58c46dc RDI: ffffffffffffffff [ 51.191073] RBP: 00005601c91e6c88 R08: 00007ffec58c47a0 R09: 0101010101010101 [ 51.201333] R10: 0000000000000000 R11: 0000000000000246 R12: 00005601caae7af0 [ 51.210434] R13: 00005601c91e4fb4 R14: 0000000000000028 R15: 00005601c91e6ca0 [ 51.222756] Kernel Offset: disabled [ 51.228450] Rebooting in 86400 seconds..