[ 44.056328] audit: type=1800 audit(1569066503.595:31): pid=7659 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2469 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: [ 55.073615] kauditd_printk_skb: 3 callbacks suppressed [ 55.073631] audit: type=1400 audit(1569066514.675:35): avc: denied { map } for pid=7832 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 '10.128.0.42' (ECDSA) to the list of known hosts. executing program [ 61.537718] audit: type=1400 audit(1569066521.135:36): avc: denied { map } for pid=7844 comm="syz-executor254" path="/root/syz-executor254428454" 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 [ 61.568440] ================================================================== [ 61.576064] BUG: KASAN: use-after-free in wait_consider_task+0x2f44/0x3910 [ 61.583080] Read of size 4 at addr ffff88808b22c634 by task sshd/7842 [ 61.589841] [ 61.591473] CPU: 0 PID: 7842 Comm: sshd Not tainted 4.19.75 #0 [ 61.597712] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.609921] Call Trace: [ 61.612529] dump_stack+0x172/0x1f0 [ 61.616180] ? wait_consider_task+0x2f44/0x3910 [ 61.621392] print_address_description.cold+0x7c/0x20d [ 61.626748] ? wait_consider_task+0x2f44/0x3910 [ 61.631443] kasan_report.cold+0x8c/0x2ba [ 61.635628] __asan_report_load4_noabort+0x14/0x20 [ 61.640570] wait_consider_task+0x2f44/0x3910 [ 61.645140] ? mark_held_locks+0x100/0x100 [ 61.649631] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 61.654788] ? add_wait_queue+0x112/0x170 [ 61.659550] ? release_task+0x1630/0x1630 [ 61.664168] ? lock_acquire+0x16f/0x3f0 [ 61.668911] ? do_wait+0x3aa/0x9d0 [ 61.672642] ? kasan_check_write+0x14/0x20 [ 61.677016] do_wait+0x439/0x9d0 [ 61.680380] ? wait_consider_task+0x3910/0x3910 [ 61.685051] ? mark_held_locks+0x100/0x100 [ 61.689388] kernel_wait4+0x171/0x290 [ 61.693449] ? __ia32_sys_waitid+0x140/0x140 [ 61.697853] ? task_stopped_code+0x180/0x180 [ 61.702280] __do_sys_wait4+0x147/0x160 [ 61.706277] ? kernel_wait4+0x290/0x290 [ 61.710265] ? kasan_check_read+0x11/0x20 [ 61.714519] ? _copy_to_user+0xc9/0x120 [ 61.718625] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 61.724186] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 61.729322] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 61.734208] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 61.738961] ? do_syscall_64+0x26/0x620 [ 61.742959] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 61.748423] ? do_syscall_64+0x26/0x620 [ 61.752399] __x64_sys_wait4+0x97/0xf0 [ 61.756281] do_syscall_64+0xfd/0x620 [ 61.760074] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 61.765386] RIP: 0033:0x7f3eba144a3e [ 61.769131] 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 [ 61.789542] RSP: 002b:00007ffc35641700 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 61.797253] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3eba144a3e [ 61.804719] RDX: 0000000000000001 RSI: 00007ffc3564173c RDI: ffffffffffffffff [ 61.812193] RBP: 00005621ba900c88 R08: 00007ffc35641800 R09: 0101010101010101 [ 61.819454] R10: 0000000000000000 R11: 0000000000000246 R12: 00005621bbd22c00 [ 61.826716] R13: 00005621ba8fefb4 R14: 0000000000000028 R15: 00005621ba900ca0 [ 61.833995] [ 61.835623] Allocated by task 7842: [ 61.840733] save_stack+0x45/0xd0 [ 61.844187] kasan_kmalloc+0xce/0xf0 [ 61.847937] kasan_slab_alloc+0xf/0x20 [ 61.851826] kmem_cache_alloc_node+0x144/0x710 [ 61.856397] copy_process.part.0+0x1ce0/0x7a30 [ 61.862474] _do_fork+0x257/0xfd0 [ 61.865914] __x64_sys_clone+0xbf/0x150 [ 61.869874] do_syscall_64+0xfd/0x620 [ 61.873677] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 61.882233] [ 61.884377] Freed by task 0: [ 61.887407] save_stack+0x45/0xd0 [ 61.890861] __kasan_slab_free+0x102/0x150 [ 61.895090] kasan_slab_free+0xe/0x10 [ 61.898876] kmem_cache_free+0x86/0x260 [ 61.902837] free_task+0xdd/0x120 [ 61.906284] __put_task_struct+0x20f/0x4c0 [ 61.910545] finish_task_switch+0x52b/0x780 [ 61.914969] __schedule+0x86e/0x1dc0 [ 61.919218] schedule_idle+0x58/0x80 [ 61.923055] do_idle+0x192/0x560 [ 61.926596] cpu_startup_entry+0xc8/0xe0 [ 61.930832] start_secondary+0x3e8/0x5b0 [ 61.934914] secondary_startup_64+0xa4/0xb0 [ 61.939225] [ 61.940926] The buggy address belongs to the object at ffff88808b22c1c0 [ 61.940926] which belongs to the cache task_struct of size 6080 [ 61.953760] The buggy address is located 1140 bytes inside of [ 61.953760] 6080-byte region [ffff88808b22c1c0, ffff88808b22d980) [ 61.965796] The buggy address belongs to the page: [ 61.970812] page:ffffea00022c8b00 count:1 mapcount:0 mapping:ffff88812c26d800 index:0x0 compound_mapcount: 0 [ 61.980898] flags: 0x1fffc0000008100(slab|head) [ 61.986066] raw: 01fffc0000008100 ffffea00023dee88 ffffea0002a14888 ffff88812c26d800 [ 61.994155] raw: 0000000000000000 ffff88808b22c1c0 0000000100000001 0000000000000000 [ 62.002050] page dumped because: kasan: bad access detected [ 62.007764] [ 62.009415] Memory state around the buggy address: [ 62.014428] ffff88808b22c500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 62.022212] ffff88808b22c580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 62.029650] >ffff88808b22c600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 62.036996] ^ [ 62.041916] ffff88808b22c680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 62.049271] ffff88808b22c700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 62.056615] ================================================================== [ 62.064004] Disabling lock debugging due to kernel taint [ 62.069910] Kernel panic - not syncing: panic_on_warn set ... [ 62.069910] [ 62.077299] CPU: 0 PID: 7842 Comm: sshd Tainted: G B 4.19.75 #0 [ 62.084643] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 62.094298] Call Trace: [ 62.096887] dump_stack+0x172/0x1f0 [ 62.100626] ? wait_consider_task+0x2f44/0x3910 [ 62.105316] panic+0x263/0x507 [ 62.108594] ? __warn_printk+0xf3/0xf3 [ 62.112490] ? retint_kernel+0x2d/0x2d [ 62.116548] ? trace_hardirqs_on+0x5e/0x220 [ 62.120860] ? wait_consider_task+0x2f44/0x3910 [ 62.125714] kasan_end_report+0x47/0x4f [ 62.129673] kasan_report.cold+0xa9/0x2ba [ 62.133830] __asan_report_load4_noabort+0x14/0x20 [ 62.138754] wait_consider_task+0x2f44/0x3910 [ 62.143332] ? mark_held_locks+0x100/0x100 [ 62.147568] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 62.152663] ? add_wait_queue+0x112/0x170 [ 62.156803] ? release_task+0x1630/0x1630 [ 62.160935] ? lock_acquire+0x16f/0x3f0 [ 62.164904] ? do_wait+0x3aa/0x9d0 [ 62.168439] ? kasan_check_write+0x14/0x20 [ 62.172659] do_wait+0x439/0x9d0 [ 62.176095] ? wait_consider_task+0x3910/0x3910 [ 62.180744] ? mark_held_locks+0x100/0x100 [ 62.185081] kernel_wait4+0x171/0x290 [ 62.188911] ? __ia32_sys_waitid+0x140/0x140 [ 62.194504] ? task_stopped_code+0x180/0x180 [ 62.198907] __do_sys_wait4+0x147/0x160 [ 62.202960] ? kernel_wait4+0x290/0x290 [ 62.206924] ? kasan_check_read+0x11/0x20 [ 62.212102] ? _copy_to_user+0xc9/0x120 [ 62.216146] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 62.221679] ? __x64_sys_rt_sigprocmask+0x21d/0x2e0 [ 62.226679] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 62.231422] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 62.236160] ? do_syscall_64+0x26/0x620 [ 62.240142] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 62.245770] ? do_syscall_64+0x26/0x620 [ 62.249751] __x64_sys_wait4+0x97/0xf0 [ 62.253645] do_syscall_64+0xfd/0x620 [ 62.257438] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 62.262618] RIP: 0033:0x7f3eba144a3e [ 62.266405] 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 [ 62.285382] RSP: 002b:00007ffc35641700 EFLAGS: 00000246 ORIG_RAX: 000000000000003d [ 62.293187] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3eba144a3e [ 62.300908] RDX: 0000000000000001 RSI: 00007ffc3564173c RDI: ffffffffffffffff [ 62.308423] RBP: 00005621ba900c88 R08: 00007ffc35641800 R09: 0101010101010101 [ 62.315966] R10: 0000000000000000 R11: 0000000000000246 R12: 00005621bbd22c00 [ 62.324004] R13: 00005621ba8fefb4 R14: 0000000000000028 R15: 00005621ba900ca0 [ 62.333451] Kernel Offset: disabled [ 62.337104] Rebooting in 86400 seconds..