[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 15.898571] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [ 16.512200] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [ 16.684520] random: sshd: uninitialized urandom read (32 bytes read, 34 bits of entropy available) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 17.508360] random: sshd: uninitialized urandom read (32 bytes read, 98 bits of entropy available) [ 17.678089] random: sshd: uninitialized urandom read (32 bytes read, 102 bits of entropy available) Warning: Permanently added '10.128.0.13' (ECDSA) to the list of known hosts. [ 23.052356] random: sshd: uninitialized urandom read (32 bytes read, 109 bits of entropy available) executing program [ 23.154922] ================================================================== [ 23.162334] BUG: KASAN: use-after-free in __lock_acquire+0x387e/0x4b50 [ 23.168980] Read of size 8 at addr ffff8801d0de2d38 by task syzkaller288609/3309 [ 23.176480] [ 23.178076] CPU: 0 PID: 3309 Comm: syzkaller288609 Not tainted 4.4.110-gdac1439 #20 [ 23.185834] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 23.195156] 0000000000000000 050805391b356546 ffff8801d00e78d0 ffffffff81d04e3d [ 23.203102] ffffea0007437880 ffff8801d0de2d38 0000000000000000 ffff8801d0de2d38 [ 23.211047] 0000000000000000 ffff8801d00e7908 ffffffff814fd1f3 ffff8801d0de2d38 [ 23.219000] Call Trace: [ 23.221556] [] dump_stack+0xc1/0x124 [ 23.226894] [] print_address_description+0x73/0x260 [ 23.233526] [] kasan_report+0x285/0x370 [ 23.239117] [] ? __lock_acquire+0x387e/0x4b50 [ 23.245227] [] __asan_report_load8_noabort+0x14/0x20 [ 23.251943] [] __lock_acquire+0x387e/0x4b50 [ 23.257878] [] ? __lock_acquire+0xb5f/0x4b50 [ 23.263900] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 23.270877] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 23.277854] [] ? mark_held_locks+0xaf/0x100 [ 23.283791] [] lock_acquire+0x15e/0x460 [ 23.289383] [] ? remove_wait_queue+0x14/0x40 [ 23.295408] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 23.301701] [] ? remove_wait_queue+0x14/0x40 [ 23.307726] [] remove_wait_queue+0x14/0x40 [ 23.313577] [] ep_unregister_pollwait.isra.6+0xa8/0x220 [ 23.320555] [] ? ep_unregister_pollwait.isra.6+0x114/0x220 [ 23.327801] [] ? ep_free+0x1c0/0x1c0 [ 23.333128] [] ep_free+0x93/0x1c0 [ 23.338194] [] ? ep_free+0x1c0/0x1c0 [ 23.343534] [] ep_eventpoll_release+0x44/0x60 [ 23.349644] [] __fput+0x233/0x6d0 [ 23.354713] [] ____fput+0x15/0x20 [ 23.359782] [] task_work_run+0x104/0x180 [ 23.365471] [] do_exit+0x871/0x2a20 [ 23.370712] [] ? release_task+0x1240/0x1240 [ 23.376652] [] ? SyS_epoll_create+0x190/0x190 [ 23.382764] [] do_group_exit+0x108/0x320 [ 23.388441] [] ? lockdep_sys_exit_thunk+0x12/0x14 [ 23.394900] [] SyS_exit_group+0x1d/0x20 [ 23.400493] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 23.407035] [ 23.408628] Allocated by task 3309: [ 23.412218] [] save_stack_trace+0x26/0x50 [ 23.418098] [] save_stack+0x43/0xd0 [ 23.423457] [] kasan_kmalloc+0xad/0xe0 [ 23.429071] [] kmem_cache_alloc_trace+0x100/0x2b0 [ 23.435639] [] binder_get_thread+0x181/0x7a0 [ 23.441780] [] binder_poll+0x4a/0x210 [ 23.447308] [] SyS_epoll_ctl+0x10b1/0x2050 [ 23.453274] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 23.459935] [ 23.461539] Freed by task 3309: [ 23.464780] [] save_stack_trace+0x26/0x50 [ 23.470656] [] save_stack+0x43/0xd0 [ 23.476011] [] kasan_slab_free+0x72/0xc0 [ 23.481797] [] kfree+0xfc/0x300 [ 23.486807] [] binder_thread_dec_tmpref+0x1c1/0x250 [ 23.493553] [] binder_thread_release+0x27d/0x540 [ 23.500038] [] binder_ioctl+0xb94/0x12e0 [ 23.505829] [] do_vfs_ioctl+0x7aa/0xee0 [ 23.511534] [] SyS_ioctl+0x8f/0xc0 [ 23.516805] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 23.523464] [ 23.525060] The buggy address belongs to the object at ffff8801d0de2c80 [ 23.525060] which belongs to the cache kmalloc-512 of size 512 [ 23.537683] The buggy address is located 184 bytes inside of [ 23.537683] 512-byte region [ffff8801d0de2c80, ffff8801d0de2e80) [ 23.549521] The buggy address belongs to the page: [ 25.064275] PANIC: double fault, error_code: 0x0 [ 25.069063] CPU: 0 PID: 3309 Comm: syzkaller288609 Not tainted 4.4.110-gdac1439 #20 [ 25.076824] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 25.087809] task: ffff8801d1f32f80 task.stack: ffff8801d00e0000 [ 25.093830] RIP: 0010:[] [] dump_page_badflags+0x1a/0x250 [ 25.102930] RSP: 0018:ffff880100000000 EFLAGS: 00010086 [ 25.108344] RAX: ffff8801d1f32f80 RBX: ffffea0007437880 RCX: ffffffff8148f740 [ 25.115581] RDX: 0000000000000000 RSI: ffffffff838a8320 RDI: ffffea0007437880 [ 25.122825] RBP: ffff880100000030 R08: 0000000000000001 R09: 0000000000000000 [ 25.130060] R10: 0000000000000002 R11: fffffbfff0ad781e R12: 0000000000000000 [ 25.137304] R13: ffffffff838a8320 R14: 0000000000000000 R15: 0000000000000000 [ 25.144542] FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 [ 25.152740] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 25.158586] CR2: ffff8800fffffff8 CR3: 000000000420c000 CR4: 0000000000160670 [ 25.165825] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 25.173328] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 25.180563] Stack: [ 25.182674] [ 25.184264] Call Trace: [ 25.186812] [ 25.188837] 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 61 06 ed ff 48 8d 7b 10 48 b8 00 00 00 00 00 fc ff df 48 89 [ 25.217720] Kernel panic - not syncing: Machine halted. [ 25.223049] CPU: 0 PID: 3309 Comm: syzkaller288609 Not tainted 4.4.110-gdac1439 #20 [ 25.230805] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 25.240141] 0000000000000000 050805391b356546 ffff8801db20ce38 ffffffff81d04e3d [ 25.248091] ffffffff838367c0 ffff8801db20cf10 ffffffff83808040 ffff880100000000 [ 25.256039] 0000000000000000 ffff8801db20cf00 ffffffff814197fa 0000000041b58ab3 [ 25.263986] Call Trace: [ 25.266532] <#DF> [] dump_stack+0xc1/0x124 [ 25.272591] [] panic+0x1aa/0x388 [ 25.277571] [] ? percpu_up_read.constprop.45+0xe1/0xe1 [ 25.284464] [] ? vprintk_emit+0x242/0x850 [ 25.290576] [] ? dump_page_badflags+0x2f/0x250 [ 25.296858] [] ? vprintk_emit+0x242/0x850 [ 25.302622] [] df_debug+0x2d/0x30 [ 25.307692] [] do_double_fault+0x10b/0x210 [ 25.313541] [] double_fault+0x2d/0x40 [ 25.318953] [] ? dump_page_badflags+0x180/0x250 [ 25.325234] [] ? dump_page_badflags+0x1a/0x250 [ 25.331425] <> [ 25.334761] Dumping ftrace buffer: [ 25.338557] (ftrace buffer empty) [ 25.342233] Kernel Offset: disabled [ 25.345823] Rebooting in 86400 seconds..