[ 17.091346] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 22.148043] random: sshd: uninitialized urandom read (32 bytes read, 38 bits of entropy available) [ 22.492692] random: sshd: uninitialized urandom read (32 bytes read, 39 bits of entropy available) [ 23.216316] random: sshd: uninitialized urandom read (32 bytes read, 81 bits of entropy available) [ 23.386538] random: sshd: uninitialized urandom read (32 bytes read, 85 bits of entropy available) Warning: Permanently added '10.128.15.238' (ECDSA) to the list of known hosts. [ 28.776357] random: sshd: uninitialized urandom read (32 bytes read, 92 bits of entropy available) executing program [ 28.873418] ================================================================== [ 28.880817] BUG: KASAN: use-after-free in __lock_acquire+0x387e/0x4b50 [ 28.887452] Read of size 8 at addr ffff8800b448a5b8 by task syzkaller745956/3323 [ 28.894949] [ 28.896547] CPU: 0 PID: 3323 Comm: syzkaller745956 Not tainted 4.4.111-g7902639 #18 [ 28.904304] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.913630] 0000000000000000 9bcc4791359c3161 ffff8801d0ebf850 ffffffff81d0509d [ 28.921580] ffffea0002d12280 ffff8800b448a5b8 0000000000000000 ffff8800b448a5b8 [ 28.929538] 0000000000000000 ffff8801d0ebf888 ffffffff814fd433 ffff8800b448a5b8 [ 28.937499] Call Trace: [ 28.940057] [] dump_stack+0xc1/0x124 [ 28.945398] [] print_address_description+0x73/0x260 [ 28.952034] [] kasan_report+0x285/0x370 [ 28.957627] [] ? __lock_acquire+0x387e/0x4b50 [ 28.963738] [] __asan_report_load8_noabort+0x14/0x20 [ 28.970454] [] __lock_acquire+0x387e/0x4b50 [ 28.976392] [] ? __lock_acquire+0xb5f/0x4b50 [ 28.982424] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 28.989405] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 28.996216] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 29.003198] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 29.010179] [] lock_acquire+0x15e/0x460 [ 29.015771] [] ? remove_wait_queue+0x14/0x40 [ 29.021797] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 29.028081] [] ? remove_wait_queue+0x14/0x40 [ 29.034106] [] remove_wait_queue+0x14/0x40 [ 29.039961] [] ep_unregister_pollwait.isra.6+0xa8/0x220 [ 29.046941] [] ? ep_unregister_pollwait.isra.6+0x114/0x220 [ 29.054178] [] ? ep_free+0x1c0/0x1c0 [ 29.059508] [] ep_free+0x93/0x1c0 [ 29.064576] [] ? ep_free+0x1c0/0x1c0 [ 29.069905] [] ep_eventpoll_release+0x44/0x60 [ 29.076016] [] __fput+0x233/0x6d0 [ 29.081093] [] ____fput+0x15/0x20 [ 29.086165] [] task_work_run+0x104/0x180 [ 29.091841] [] do_exit+0x871/0x2a20 [ 29.097084] [] ? handle_mm_fault+0x192d/0x3190 [ 29.103279] [] ? handle_mm_fault+0x3f2/0x3190 [ 29.109389] [] ? release_task+0x1240/0x1240 [ 29.115327] [] do_group_exit+0x108/0x320 [ 29.121003] [] SyS_exit_group+0x1d/0x20 [ 29.126593] [] ? do_group_exit+0x320/0x320 [ 29.132446] [] do_fast_syscall_32+0x314/0x890 [ 29.138559] [] sysenter_flags_fixed+0xd/0x17 [ 29.144592] [ 29.146187] Allocated by task 3323: [ 29.149784] [] save_stack_trace+0x26/0x50 [ 29.155667] [] save_stack+0x43/0xd0 [ 29.161034] [] kasan_kmalloc+0xad/0xe0 [ 29.166652] [] kmem_cache_alloc_trace+0x100/0x2b0 [ 29.173225] [] binder_get_thread+0x181/0x7a0 [ 29.179381] [] binder_poll+0x4a/0x210 [ 29.184914] [] SyS_epoll_ctl+0x10b1/0x2050 [ 29.190899] [] do_fast_syscall_32+0x314/0x890 [ 29.197130] [] sysenter_flags_fixed+0xd/0x17 [ 29.203289] [ 29.204889] Freed by task 3323: [ 29.208127] [] save_stack_trace+0x26/0x50 [ 29.214003] [] save_stack+0x43/0xd0 [ 29.219357] [] kasan_slab_free+0x72/0xc0 [ 29.225145] [] kfree+0xfc/0x300 [ 29.230158] [] binder_thread_dec_tmpref+0x1c1/0x250 [ 29.236905] [] binder_thread_release+0x27d/0x540 [ 29.243400] [] binder_ioctl+0xb94/0x12e0 [ 29.249191] [] compat_SyS_ioctl+0x28a/0x2540 [ 29.255332] [] do_fast_syscall_32+0x314/0x890 [ 29.261555] [] sysenter_flags_fixed+0xd/0x17 [ 29.267697] [ 29.269300] The buggy address belongs to the object at ffff8800b448a500 [ 29.269300] which belongs to the cache kmalloc-512 of size 512 [ 29.281920] The buggy address is located 184 bytes inside of [ 29.281920] 512-byte region [ffff8800b448a500, ffff8800b448a700) [ 29.293769] The buggy address belongs to the page: [ 30.801842] PANIC: double fault, error_code: 0x0 [ 30.806628] CPU: 0 PID: 3323 Comm: syzkaller745956 Not tainted 4.4.111-g7902639 #18 [ 30.814388] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.823710] task: ffff8800b5010000 task.stack: ffff8801d0eb8000 [ 30.829747] RIP: 0010:[] [] dump_page_badflags+0x1a/0x250 [ 30.838590] RSP: 0018:ffff880100000000 EFLAGS: 00010086 [ 30.844002] RAX: ffff8800b5010000 RBX: ffffea0002d12280 RCX: ffffffff8148f980 [ 30.851237] RDX: 0000000000000000 RSI: ffffffff838a8360 RDI: ffffea0002d12280 [ 30.858470] RBP: ffff880100000030 R08: 0000000000000001 R09: 0000000000000000 [ 30.865708] R10: 0000000000000002 R11: fffffbfff0ad781e R12: 0000000000000000 [ 30.872946] R13: ffffffff838a8360 R14: 0000000000000000 R15: 0000000000000000 [ 30.880184] FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 [ 30.888375] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 30.894223] CR2: ffff8800fffffff8 CR3: 000000000420c000 CR4: 0000000000160670 [ 30.902125] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 30.909361] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 30.916596] Stack: [ 30.918710] [ 30.920301] Call Trace: [ 30.922846] [ 30.924872] 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 [ 30.951446] Kernel panic - not syncing: Machine halted. [ 30.956773] CPU: 0 PID: 3323 Comm: syzkaller745956 Not tainted 4.4.111-g7902639 #18 [ 30.964533] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.973849] 0000000000000000 9bcc4791359c3161 ffff8801db20ce38 ffffffff81d0509d [ 30.981801] ffffffff838367c0 ffff8801db20cf10 ffffffff83808040 ffff880100000000 [ 30.989744] 0000000000000000 ffff8801db20cf00 ffffffff81419a3a 0000000041b58ab3 [ 30.997689] Call Trace: [ 31.000233] <#DF> [] dump_stack+0xc1/0x124 [ 31.006292] [] panic+0x1aa/0x388 [ 31.011272] [] ? percpu_up_read.constprop.45+0xe1/0xe1 [ 31.018172] [] ? vprintk_emit+0x242/0x850 [ 31.023935] [] ? dump_page_badflags+0x2f/0x250 [ 31.030129] [] ? vprintk_emit+0x242/0x850 [ 31.035897] [] df_debug+0x2d/0x30 [ 31.040967] [] do_double_fault+0x10b/0x210 [ 31.046818] [] double_fault+0x2d/0x40 [ 31.052232] [] ? dump_page_badflags+0x180/0x250 [ 31.058519] [] ? dump_page_badflags+0x1a/0x250 [ 31.064712] <> [ 31.067681] Dumping ftrace buffer: [ 31.071476] (ftrace buffer empty) [ 31.075150] Kernel Offset: disabled [ 31.078741] Rebooting in 86400 seconds..