[ 41.355351] audit: type=1800 audit(1569065033.169:32): pid=7492 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 periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 46.764366] kauditd_printk_skb: 2 callbacks suppressed [ 46.764380] audit: type=1400 audit(1569065038.619:35): avc: denied { map } for pid=7664 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 '10.128.0.77' (ECDSA) to the list of known hosts. executing program [ 53.392598] audit: type=1400 audit(1569065045.249:36): avc: denied { map } for pid=7676 comm="syz-executor090" path="/root/syz-executor090077788" 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 [ 53.422090] ================================================================== [ 53.429609] BUG: KASAN: use-after-free in wait_consider_task+0x1b51/0x3910 [ 53.436618] Read of size 4 at addr ffff888091d8a7ac by task sshd/7674 [ 53.443279] [ 53.444919] CPU: 0 PID: 7674 Comm: sshd Not tainted 4.19.75 #0 [ 53.451115] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 53.460560] Call Trace: [ 53.463191] dump_stack+0x172/0x1f0 [ 53.466828] ? wait_consider_task+0x1b51/0x3910 [ 53.471491] print_address_description.cold+0x7c/0x20d [ 53.476850] ? wait_consider_task+0x1b51/0x3910 [ 53.481947] kasan_report.cold+0x8c/0x2ba [ 53.486088] __asan_report_load4_noabort+0x14/0x20 [ 53.491100] wait_consider_task+0x1b51/0x3910 [ 53.495592] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 53.500684] ? add_wait_queue+0x112/0x170 [ 53.504839] ? release_task+0x1630/0x1630 [ 53.508975] ? lock_acquire+0x16f/0x3f0 [ 53.512936] ? do_wait+0x3aa/0x9d0 [ 53.516468] ? kasan_check_write+0x14/0x20 [ 53.520691] do_wait+0x439/0x9d0 [ 53.524063] ? wait_consider_task+0x3910/0x3910 [ 53.528757] ? mark_held_locks+0x100/0x100 [ 53.532991] kernel_wait4+0x171/0x290 [ 53.536783] ? __ia32_sys_waitid+0x140/0x140 [ 53.541210] ? task_stopped_code+0x180/0x180 [ 53.545609] __do_sys_wait4+0x147/0x160 [ 53.549576] ? kernel_wait4+0x290/0x290 [ 53.553545] ? kasan_check_read+0x11/0x20 [ 53.557768] ? _copy_to_user+0xc9/0x120 [ 53.561866] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 53.567409] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 53.572427] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 53.577312] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 53.582082] ? do_syscall_64+0x26/0x620 [ 53.586063] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 53.591429] ? do_syscall_64+0x26/0x620 [ 53.595405] __x64_sys_wait4+0x97/0xf0 [ 53.599285] do_syscall_64+0xfd/0x620 [ 53.603086] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 53.608264] RIP: 0033:0x7f72826b6a3e [ 53.611964] 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 [ 53.631030] RSP: 002b:00007fff57682c00 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 53.638827] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f72826b6a3e [ 53.646122] RDX: 0000000000000001 RSI: 00007fff57682c3c RDI: ffffffffffffffff [ 53.653417] RBP: 000055715315cc88 R08: 00007fff57682d00 R09: 0101010101010101 [ 53.660800] R10: 0000000000000000 R11: 0000000000000246 R12: 0000557154b40af0 [ 53.668620] R13: 000055715315afb4 R14: 0000000000000028 R15: 000055715315cca0 [ 53.679677] [ 53.682012] Allocated by task 7674: [ 53.687461] save_stack+0x45/0xd0 [ 53.691834] kasan_kmalloc+0xce/0xf0 [ 53.695567] kasan_slab_alloc+0xf/0x20 [ 53.699449] kmem_cache_alloc_node+0x144/0x710 [ 53.704217] copy_process.part.0+0x1ce0/0x7a30 [ 53.708815] _do_fork+0x257/0xfd0 [ 53.712279] __x64_sys_clone+0xbf/0x150 [ 53.716504] do_syscall_64+0xfd/0x620 [ 53.720590] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 53.725784] [ 53.727404] Freed by task 0: [ 53.730424] save_stack+0x45/0xd0 [ 53.734240] __kasan_slab_free+0x102/0x150 [ 53.738654] kasan_slab_free+0xe/0x10 [ 53.742534] kmem_cache_free+0x86/0x260 [ 53.746644] free_task+0xdd/0x120 [ 53.750189] __put_task_struct+0x20f/0x4c0 [ 53.754643] finish_task_switch+0x52b/0x780 [ 53.760105] __schedule+0x86e/0x1dc0 [ 53.763826] schedule_idle+0x58/0x80 [ 53.767640] do_idle+0x192/0x560 [ 53.771011] cpu_startup_entry+0xc8/0xe0 [ 53.775060] start_secondary+0x3e8/0x5b0 [ 53.779109] secondary_startup_64+0xa4/0xb0 [ 53.783497] [ 53.785114] The buggy address belongs to the object at ffff888091d8a340 [ 53.785114] which belongs to the cache task_struct of size 6080 [ 53.798388] The buggy address is located 1132 bytes inside of [ 53.798388] 6080-byte region [ffff888091d8a340, ffff888091d8bb00) [ 53.810962] The buggy address belongs to the page: [ 53.815972] page:ffffea0002476280 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 53.827088] flags: 0x1fffc0000008100(slab|head) [ 53.831893] raw: 01fffc0000008100 ffffea0002404b08 ffffea00023d2988 ffff88812c26d800 [ 53.840165] raw: 0000000000000000 ffff888091d8a340 0000000100000001 0000000000000000 [ 53.848252] page dumped because: kasan: bad access detected [ 53.854561] [ 53.856211] Memory state around the buggy address: [ 53.862497] ffff888091d8a680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 53.870712] ffff888091d8a700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 53.878386] >ffff888091d8a780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 53.885854] ^ [ 53.890626] ffff888091d8a800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 53.897989] ffff888091d8a880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 53.905372] ================================================================== [ 53.912715] Disabling lock debugging due to kernel taint [ 53.918253] Kernel panic - not syncing: panic_on_warn set ... [ 53.918253] [ 53.925632] CPU: 0 PID: 7674 Comm: sshd Tainted: G B 4.19.75 #0 [ 53.932997] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 53.942581] Call Trace: [ 53.945269] dump_stack+0x172/0x1f0 [ 53.948898] ? wait_consider_task+0x1b51/0x3910 [ 53.953567] panic+0x263/0x507 [ 53.956755] ? __warn_printk+0xf3/0xf3 [ 53.960637] ? retint_kernel+0x2d/0x2d [ 53.964511] ? trace_hardirqs_on+0x5e/0x220 [ 53.968830] ? wait_consider_task+0x1b51/0x3910 [ 53.973615] kasan_end_report+0x47/0x4f [ 53.977588] kasan_report.cold+0xa9/0x2ba [ 53.981758] __asan_report_load4_noabort+0x14/0x20 [ 53.986688] wait_consider_task+0x1b51/0x3910 [ 53.991175] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 53.996261] ? add_wait_queue+0x112/0x170 [ 54.000407] ? release_task+0x1630/0x1630 [ 54.004559] ? lock_acquire+0x16f/0x3f0 [ 54.008535] ? do_wait+0x3aa/0x9d0 [ 54.012075] ? kasan_check_write+0x14/0x20 [ 54.016296] do_wait+0x439/0x9d0 [ 54.019670] ? wait_consider_task+0x3910/0x3910 [ 54.024323] ? mark_held_locks+0x100/0x100 [ 54.028607] kernel_wait4+0x171/0x290 [ 54.032565] ? __ia32_sys_waitid+0x140/0x140 [ 54.037050] ? task_stopped_code+0x180/0x180 [ 54.041579] __do_sys_wait4+0x147/0x160 [ 54.045544] ? kernel_wait4+0x290/0x290 [ 54.049514] ? kasan_check_read+0x11/0x20 [ 54.053661] ? _copy_to_user+0xc9/0x120 [ 54.057727] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 54.063431] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 54.068435] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 54.073176] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 54.077932] ? do_syscall_64+0x26/0x620 [ 54.081980] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.087354] ? do_syscall_64+0x26/0x620 [ 54.091318] __x64_sys_wait4+0x97/0xf0 [ 54.095281] do_syscall_64+0xfd/0x620 [ 54.099088] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.104370] RIP: 0033:0x7f72826b6a3e [ 54.108068] 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 [ 54.127416] RSP: 002b:00007fff57682c00 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 54.135129] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f72826b6a3e [ 54.142394] RDX: 0000000000000001 RSI: 00007fff57682c3c RDI: ffffffffffffffff [ 54.149699] RBP: 000055715315cc88 R08: 00007fff57682d00 R09: 0101010101010101 [ 54.156964] R10: 0000000000000000 R11: 0000000000000246 R12: 0000557154b40af0 [ 54.164352] R13: 000055715315afb4 R14: 0000000000000028 R15: 000055715315cca0 [ 54.173456] Kernel Offset: disabled [ 54.177101] Rebooting in 86400 seconds..