[ 16.203229] random: sshd: uninitialized urandom read (32 bytes read, 32 bits of entropy available) [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 20.998260] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 21.333744] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 22.169564] random: sshd: uninitialized urandom read (32 bytes read, 98 bits of entropy available) [ 28.630290] random: sshd: uninitialized urandom read (32 bytes read, 108 bits of entropy available) Warning: Permanently added '10.128.15.230' (ECDSA) to the list of known hosts. [ 34.013637] random: sshd: uninitialized urandom read (32 bytes read, 116 bits of entropy available) executing program [ 34.109016] ================================================================== [ 34.116430] BUG: KASAN: use-after-free in __lock_acquire+0x387e/0x4b50 [ 34.123067] Read of size 8 at addr ffff8801d23aafb8 by task syzkaller750039/3327 [ 34.130577] [ 34.132177] CPU: 0 PID: 3327 Comm: syzkaller750039 Not tainted 4.4.112-g3fc4284 #32 [ 34.139936] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 34.149269] 0000000000000000 b34ea9fe7b2179aa ffff8801d09978d0 ffffffff81d054ed [ 34.157245] ffffea000748ea80 ffff8801d23aafb8 0000000000000000 ffff8801d23aafb8 [ 34.165219] 0000000000000000 ffff8801d0997908 ffffffff814fd953 ffff8801d23aafb8 [ 34.173203] Call Trace: [ 34.175762] [] dump_stack+0xc1/0x124 [ 34.181095] [] print_address_description+0x73/0x260 [ 34.187740] [] kasan_report+0x285/0x370 [ 34.193351] [] ? __lock_acquire+0x387e/0x4b50 [ 34.199470] [] __asan_report_load8_noabort+0x14/0x20 [ 34.206190] [] __lock_acquire+0x387e/0x4b50 [ 34.212141] [] ? __lock_acquire+0xb5f/0x4b50 [ 34.218167] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 34.225151] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 34.232136] [] ? mark_held_locks+0xaf/0x100 [ 34.238086] [] lock_acquire+0x15e/0x460 [ 34.243679] [] ? remove_wait_queue+0x14/0x40 [ 34.249723] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 34.256011] [] ? remove_wait_queue+0x14/0x40 [ 34.262034] [] remove_wait_queue+0x14/0x40 [ 34.267888] [] ep_unregister_pollwait.isra.6+0xa8/0x220 [ 34.274880] [] ? ep_unregister_pollwait.isra.6+0x114/0x220 [ 34.282120] [] ? ep_free+0x1c0/0x1c0 [ 34.287452] [] ep_free+0x93/0x1c0 [ 34.292524] [] ? ep_free+0x1c0/0x1c0 [ 34.297856] [] ep_eventpoll_release+0x44/0x60 [ 34.303971] [] __fput+0x233/0x6d0 [ 34.309129] [] ____fput+0x15/0x20 [ 34.314201] [] task_work_run+0x104/0x180 [ 34.319888] [] do_exit+0x871/0x2a20 [ 34.325132] [] ? release_task+0x1240/0x1240 [ 34.331082] [] ? SyS_epoll_create+0x190/0x190 [ 34.337206] [] do_group_exit+0x108/0x320 [ 34.342884] [] ? lockdep_sys_exit_thunk+0x12/0x14 [ 34.349343] [] SyS_exit_group+0x1d/0x20 [ 34.354938] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 34.361495] [ 34.363094] Allocated by task 3327: [ 34.366690] [] save_stack_trace+0x26/0x50 [ 34.372584] [] save_stack+0x43/0xd0 [ 34.377945] [] kasan_kmalloc+0xad/0xe0 [ 34.383565] [] kmem_cache_alloc_trace+0x100/0x2b0 [ 34.390150] [] binder_get_thread+0x181/0x7a0 [ 34.396297] [] binder_poll+0x4a/0x210 [ 34.401826] [] SyS_epoll_ctl+0x10b1/0x2050 [ 34.407795] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 34.414456] [ 34.416052] Freed by task 3327: [ 34.419297] [] save_stack_trace+0x26/0x50 [ 34.425176] [] save_stack+0x43/0xd0 [ 34.430538] [] kasan_slab_free+0x72/0xc0 [ 34.436335] [] kfree+0xfc/0x300 [ 34.441354] [] binder_thread_dec_tmpref+0x1c1/0x250 [ 34.448102] [] binder_thread_release+0x27d/0x540 [ 34.454588] [] binder_ioctl+0xb94/0x12e0 [ 34.460383] [] do_vfs_ioctl+0x7aa/0xee0 [ 34.466087] [] SyS_ioctl+0x8f/0xc0 [ 34.471360] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 34.478024] [ 34.479625] The buggy address belongs to the object at ffff8801d23aaf00 [ 34.479625] which belongs to the cache kmalloc-512 of size 512 [ 34.492248] The buggy address is located 184 bytes inside of [ 34.492248] 512-byte region [ffff8801d23aaf00, ffff8801d23ab100) [ 34.504087] The buggy address belongs to the page: [ 35.720392] kasan: CONFIG_KASAN_INLINE enabled [ 35.724854] kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP KASAN [ 35.737713] Dumping ftrace buffer: [ 35.741233] (ftrace buffer empty) [ 35.744919] Modules linked in: [ 35.748202] CPU: 1 PID: 1734 Comm: udevd Not tainted 4.4.112-g3fc4284 #32 [ 35.755095] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.764431] task: ffff8801d3bf5f00 task.stack: ffff8801d3088000 [ 35.770455] RIP: 0010:[] [] debug_check_no_obj_freed+0x1a8/0x9b0 [ 35.779916] RSP: 0018:ffff8801d308fc78 EFLAGS: 00010007 [ 35.785334] RAX: 0000000000000286 RBX: ffff8800b4077600 RCX: 0000000000000005 [ 35.792585] RDX: 09ebe8eaa84be9aa RSI: ffff8801d308fd08 RDI: ffffffff838a8638 [ 35.799824] RBP: ffff8801d308fd70 R08: 1ffffffff07150c7 R09: ffffffff8512b880 [ 35.807063] R10: dead000000000200 R11: 1ffff1003a611f56 R12: 0000292965676170 [ 35.814303] R13: ffff8800b4076600 R14: 4f5f4755425f4d56 R15: dffffc0000000000 [ 35.821545] FS: 00007f7ab8a027a0(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 [ 35.829750] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 35.835601] CR2: 00007f7ab8a08000 CR3: 00000001d304e000 CR4: 0000000000160670 [ 35.842853] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 35.850093] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 35.857332] Stack: [ 35.859450] ffff8801d3bf5f00 ffff8801d308fd08 ffff880100000005 0000000000000286 [ 35.867427] 1ffff1003a611f9d ffffffff85833d00 ffff8800b4078000 ffff8800b4077600 [ 35.875398] dead000000000200 4f5f4755425f4d56 00000000000d42c0 fffffbfff0b067a0 [ 35.883368] Call Trace: [ 35.885925] [] ? debug_object_active_state+0x420/0x420 [ 35.892831] [] ? kfree+0xd4/0x300 [ 35.897903] [] ? kvfree+0x36/0x60 [ 35.902974] [] ? kvfree+0x36/0x60 [ 35.908043] [] kfree+0xf1/0x300 [ 35.912953] [] ? kernfs_put_open_node.isra.3+0xf0/0xf0 [ 35.919847] [] kvfree+0x36/0x60 [ 35.924743] [] seq_release+0x51/0x70 [ 35.930087] [] kernfs_fop_release+0xcb/0x140 [ 35.936133] [] __fput+0x233/0x6d0 [ 35.941215] [] ____fput+0x15/0x20 [ 35.946293] [] task_work_run+0x104/0x180 [ 35.951991] [] exit_to_usermode_loop+0x145/0x170 [ 35.958374] [] syscall_return_slowpath+0x1b5/0x1f0 [ 35.964924] [] int_ret_from_sys_call+0x25/0xa3 [ 35.971123] Code: 48 c7 c6 40 fa 75 85 4c 8b 34 0e 4d 85 f6 0f 84 c5 03 00 00 49 ba 00 02 00 00 00 00 ad de 31 c9 48 8d 75 98 4c 89 f2 48 c1 ea 03 <42> 80 3c 3a 00 0f 85 f0 03 00 00 49 8d 7e 18 83 c1 01 49 8b 16 [ 35.997853] RIP [] debug_check_no_obj_freed+0x1a8/0x9b0 [ 36.004967] RSP [ 36.008564] ---[ end trace a38cd96bb9dee0f2 ]--- [ 36.013289] Kernel panic - not syncing: Fatal exception [ 36.052849] PANIC: double fault, error_code: 0x0 [ 36.057625] CPU: 0 PID: 3327 Comm: syzkaller750039 Tainted: G D 4.4.112-g3fc4284 #32 [ 36.066609] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 36.075946] task: ffff8801d19f8000 task.stack: ffff8801d0990000 [ 36.081971] RIP: 0010:[] [] dump_page_badflags+0x1a/0x250 [ 36.090809] RSP: 0018:ffff880100000000 EFLAGS: 00010086 [ 36.096235] RAX: ffff8801d19f8000 RBX: ffffea000748ea80 RCX: ffffffff8148fea0 [ 36.103471] RDX: 0000000000000000 RSI: ffffffff838a8620 RDI: ffffea000748ea80 [ 36.110709] RBP: ffff880100000030 R08: 0000000000000001 R09: 0000000000000000 [ 36.117949] R10: 0000000000000002 R11: fffffbfff0ad7a1e R12: 0000000000000000 [ 36.125187] R13: ffffffff838a8620 R14: 0000000000000000 R15: 0000000000000000 [ 36.132429] FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 [ 36.140621] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 36.146469] CR2: ffff8800fffffff8 CR3: 000000000420c000 CR4: 0000000000160670 [ 36.153710] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 36.160950] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 36.168202] Stack: [ 36.170320] [ 36.171914] Call Trace: [ 36.174464] [ 36.176491] Code: e2 06 00 e9 1d fd ff ff 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 57 41 56 41 55 49 89 f5 41 54 49 89 d4 53 48 89 fb 48 83 ec 08 11 01 ed ff 48 8d 7b 10 48 b8 00 00 00 00 00 fc ff df 48 89 [ 37.083805] Shutting down cpus with NMI [ 37.088278] Dumping ftrace buffer: [ 37.091793] (ftrace buffer empty) [ 37.095470] Kernel Offset: disabled [ 37.099066] Rebooting in 86400 seconds..