[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 15.497173] random: sshd: uninitialized urandom read (32 bytes read, 32 bits of entropy available) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 19.441909] random: sshd: uninitialized urandom read (32 bytes read, 36 bits of entropy available) [ 19.670316] random: sshd: uninitialized urandom read (32 bytes read, 36 bits of entropy available) [ 20.591935] random: sshd: uninitialized urandom read (32 bytes read, 107 bits of entropy available) [ 20.793265] random: sshd: uninitialized urandom read (32 bytes read, 117 bits of entropy available) Warning: Permanently added '10.128.0.54' (ECDSA) to the list of known hosts. [ 26.161753] random: sshd: uninitialized urandom read (32 bytes read, 125 bits of entropy available) executing program [ 26.259674] ================================================================== [ 26.267062] BUG: KASAN: use-after-free in __lock_acquire+0x387e/0x4b50 [ 26.273696] Read of size 8 at addr ffff8801d2f61738 by task syzkaller258209/3314 [ 26.281217] [ 26.282816] CPU: 1 PID: 3314 Comm: syzkaller258209 Not tainted 4.4.112-gca0ebb4 #29 [ 26.290576] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 26.299903] 0000000000000000 e732ee979e9801b1 ffff8801d01878d0 ffffffff81d056fd [ 26.307905] ffffea00074bd800 ffff8801d2f61738 0000000000000000 ffff8801d2f61738 [ 26.315867] 0000000000000000 ffff8801d0187908 ffffffff814fd953 ffff8801d2f61738 [ 26.323827] Call Trace: [ 26.326385] [] dump_stack+0xc1/0x124 [ 26.331725] [] print_address_description+0x73/0x260 [ 26.338354] [] kasan_report+0x285/0x370 [ 26.343945] [] ? __lock_acquire+0x387e/0x4b50 [ 26.350059] [] __asan_report_load8_noabort+0x14/0x20 [ 26.356779] [] __lock_acquire+0x387e/0x4b50 [ 26.362717] [] ? __lock_acquire+0xb5f/0x4b50 [ 26.368749] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 26.375730] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 26.382722] [] ? mark_held_locks+0xaf/0x100 [ 26.388661] [] lock_acquire+0x15e/0x460 [ 26.394253] [] ? remove_wait_queue+0x14/0x40 [ 26.400280] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 26.406567] [] ? remove_wait_queue+0x14/0x40 [ 26.412592] [] remove_wait_queue+0x14/0x40 [ 26.418452] [] ep_unregister_pollwait.isra.6+0xa8/0x220 [ 26.425432] [] ? ep_unregister_pollwait.isra.6+0x114/0x220 [ 26.432685] [] ? ep_free+0x1c0/0x1c0 [ 26.438033] [] ep_free+0x93/0x1c0 [ 26.443104] [] ? ep_free+0x1c0/0x1c0 [ 26.448434] [] ep_eventpoll_release+0x44/0x60 [ 26.454546] [] __fput+0x233/0x6d0 [ 26.459614] [] ____fput+0x15/0x20 [ 26.464690] [] task_work_run+0x104/0x180 [ 26.470368] [] do_exit+0x871/0x2a20 [ 26.475611] [] ? release_task+0x1240/0x1240 [ 26.481552] [] ? SyS_epoll_create+0x190/0x190 [ 26.487668] [] do_group_exit+0x108/0x320 [ 26.493346] [] ? lockdep_sys_exit_thunk+0x12/0x14 [ 26.499805] [] SyS_exit_group+0x1d/0x20 [ 26.505397] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 26.511940] [ 26.513536] Allocated by task 3314: [ 26.517126] [] save_stack_trace+0x26/0x50 [ 26.523012] [] save_stack+0x43/0xd0 [ 26.528374] [] kasan_kmalloc+0xad/0xe0 [ 26.534000] [] kmem_cache_alloc_trace+0x100/0x2b0 [ 26.540573] [] binder_get_thread+0x181/0x7a0 [ 26.546717] [] binder_poll+0x4a/0x210 [ 26.552253] [] SyS_epoll_ctl+0x10b1/0x2050 [ 26.558218] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 26.564879] [ 26.566474] Freed by task 3314: [ 26.569719] [] save_stack_trace+0x26/0x50 [ 26.575598] [] save_stack+0x43/0xd0 [ 26.580957] [] kasan_slab_free+0x72/0xc0 [ 26.586757] [] kfree+0xfc/0x300 [ 26.591770] [] binder_thread_dec_tmpref+0x1c1/0x250 [ 26.598516] [] binder_thread_release+0x27d/0x540 [ 26.605002] [] binder_ioctl+0xb94/0x12e0 [ 26.610806] [] do_vfs_ioctl+0x7aa/0xee0 [ 26.616511] [] SyS_ioctl+0x8f/0xc0 [ 26.621783] [] entry_SYSCALL_64_fastpath+0x16/0x92 [ 26.628443] [ 26.630039] The buggy address belongs to the object at ffff8801d2f61680 [ 26.630039] which belongs to the cache kmalloc-512 of size 512 [ 26.642665] The buggy address is located 184 bytes inside of [ 26.642665] 512-byte region [ffff8801d2f61680, ffff8801d2f61880) [ 26.654503] The buggy address belongs to the page: [ 28.078512] PANIC: double fault, error_code: 0x0 [ 28.083297] CPU: 1 PID: 3314 Comm: syzkaller258209 Not tainted 4.4.112-gca0ebb4 #29 [ 28.091057] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.100379] task: ffff8800b4a397c0 task.stack: ffff8801d0180000 [ 28.106400] RIP: 0010:[] [] dump_page_badflags+0x1a/0x250 [ 28.115240] RSP: 0018:ffff880100000000 EFLAGS: 00010086 [ 28.120660] RAX: ffff8800b4a397c0 RBX: ffffea00074bd800 RCX: ffffffff8148fea0 [ 28.127897] RDX: 0000000000000000 RSI: ffffffff838a8620 RDI: ffffea00074bd800 [ 28.135136] RBP: ffff880100000030 R08: 0000000000000001 R09: 0000000000000000 [ 28.142374] R10: 0000000000000002 R11: fffffbfff0ad7a1e R12: 0000000000000000 [ 28.149613] R13: ffffffff838a8620 R14: 0000000000000000 R15: 0000000000000000 [ 28.156852] FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 [ 28.165045] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 28.170895] CR2: ffff8800fffffff8 CR3: 000000000420c000 CR4: 0000000000160670 [ 28.178133] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 28.185371] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 28.192606] Stack: [ 28.194719] [ 28.196313] Call Trace: [ 28.198862] [ 28.200892] 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 [ 28.227689] Kernel panic - not syncing: Machine halted. [ 28.233021] CPU: 1 PID: 3314 Comm: syzkaller258209 Not tainted 4.4.112-gca0ebb4 #29 [ 28.240779] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.250101] 0000000000000000 e732ee979e9801b1 ffff8801db30ce38 ffffffff81d056fd [ 28.258061] ffffffff83836a60 ffff8801db30cf10 ffffffff83808040 ffff880100000000 [ 28.266025] 0000000000000000 ffff8801db30cf00 ffffffff81419dca 0000000041b58ab3 [ 28.273987] Call Trace: [ 28.276535] <#DF> [] dump_stack+0xc1/0x124 [ 28.282599] [] panic+0x1aa/0x388 [ 28.287592] [] ? percpu_up_read.constprop.45+0xe1/0xe1 [ 28.294494] [] ? vprintk_emit+0x242/0x850 [ 28.300259] [] ? dump_page_badflags+0x2f/0x250 [ 28.306459] [] ? vprintk_emit+0x242/0x850 [ 28.312228] [] df_debug+0x2d/0x30 [ 28.317302] [] do_double_fault+0x10b/0x210 [ 28.323155] [] double_fault+0x2d/0x40 [ 28.328573] [] ? dump_page_badflags+0x180/0x250 [ 28.334859] [] ? dump_page_badflags+0x1a/0x250 [ 28.341060] <> [ 28.344404] Dumping ftrace buffer: [ 28.348206] (ftrace buffer empty) [ 28.351883] Kernel Offset: disabled [ 28.355476] Rebooting in 86400 seconds..