[ 15.721943] 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: [ 20.364312] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 20.640825] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 21.481914] random: sshd: uninitialized urandom read (32 bytes read, 102 bits of entropy available) [ 21.660832] random: sshd: uninitialized urandom read (32 bytes read, 107 bits of entropy available) Warning: Permanently added '10.128.0.13' (ECDSA) to the list of known hosts. [ 27.039482] random: sshd: uninitialized urandom read (32 bytes read, 115 bits of entropy available) executing program [ 27.141182] ================================================================== [ 27.148579] BUG: KASAN: use-after-free in __lock_acquire+0x387e/0x4b50 [ 27.155218] Read of size 8 at addr ffff8800b4768838 by task syzkaller553132/3311 [ 27.162714] [ 27.164320] CPU: 0 PID: 3311 Comm: syzkaller553132 Not tainted 4.4.110-gdac1439 #13 [ 27.172076] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 27.181404] 0000000000000000 e020a353c791c67d ffff8801d136f850 ffffffff81d04e3d [ 27.189356] ffffea0002d1da00 ffff8800b4768838 0000000000000000 ffff8800b4768838 [ 27.197295] 0000000000000000 ffff8801d136f888 ffffffff814fd1f3 ffff8800b4768838 [ 27.205232] Call Trace: [ 27.207786] [] dump_stack+0xc1/0x124 [ 27.213116] [] print_address_description+0x73/0x260 [ 27.219752] [] kasan_report+0x285/0x370 [ 27.225339] [] ? __lock_acquire+0x387e/0x4b50 [ 27.231449] [] __asan_report_load8_noabort+0x14/0x20 [ 27.238165] [] __lock_acquire+0x387e/0x4b50 [ 27.244103] [] ? __lock_acquire+0xb5f/0x4b50 [ 27.250125] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 27.257106] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 27.263919] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 27.270896] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 27.277872] [] lock_acquire+0x15e/0x460 [ 27.283461] [] ? remove_wait_queue+0x14/0x40 [ 27.289486] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 27.295775] [] ? remove_wait_queue+0x14/0x40 [ 27.301797] [] remove_wait_queue+0x14/0x40 [ 27.307655] [] ep_unregister_pollwait.isra.6+0xa8/0x220 [ 27.314634] [] ? ep_unregister_pollwait.isra.6+0x114/0x220 [ 27.321871] [] ? ep_free+0x1c0/0x1c0 [ 27.327198] [] ep_free+0x93/0x1c0 [ 27.332266] [] ? ep_free+0x1c0/0x1c0 [ 27.337592] [] ep_eventpoll_release+0x44/0x60 [ 27.343700] [] __fput+0x233/0x6d0 [ 27.348768] [] ____fput+0x15/0x20 [ 27.353836] [] task_work_run+0x104/0x180 [ 27.359516] [] do_exit+0x871/0x2a20 [ 27.364763] [] ? handle_mm_fault+0x192d/0x3190 [ 27.370959] [] ? handle_mm_fault+0x3f2/0x3190 [ 27.377067] [] ? release_task+0x1240/0x1240 [ 27.383002] [] do_group_exit+0x108/0x320 [ 27.388679] [] SyS_exit_group+0x1d/0x20 [ 27.394272] [] ? do_group_exit+0x320/0x320 [ 27.400121] [] do_fast_syscall_32+0x314/0x890 [ 27.406233] [] sysenter_flags_fixed+0xd/0x17 [ 27.412256] [ 27.413855] Allocated by task 3311: [ 27.417445] [] save_stack_trace+0x26/0x50 [ 27.423330] [] save_stack+0x43/0xd0 [ 27.428684] [] kasan_kmalloc+0xad/0xe0 [ 27.434297] [] kmem_cache_alloc_trace+0x100/0x2b0 [ 27.440866] [] binder_get_thread+0x181/0x7a0 [ 27.447005] [] binder_poll+0x4a/0x210 [ 27.452538] [] SyS_epoll_ctl+0x10b1/0x2050 [ 27.458499] [] do_fast_syscall_32+0x314/0x890 [ 27.464721] [] sysenter_flags_fixed+0xd/0x17 [ 27.470862] [ 27.472459] Freed by task 3311: [ 27.475699] [] save_stack_trace+0x26/0x50 [ 27.481572] [] save_stack+0x43/0xd0 [ 27.486926] [] kasan_slab_free+0x72/0xc0 [ 27.492718] [] kfree+0xfc/0x300 [ 27.497720] [] binder_thread_dec_tmpref+0x1c1/0x250 [ 27.504463] [] binder_thread_release+0x27d/0x540 [ 27.510949] [] binder_ioctl+0xb94/0x12e0 [ 27.516738] [] compat_SyS_ioctl+0x28a/0x2540 [ 27.522879] [] do_fast_syscall_32+0x314/0x890 [ 27.529097] [] sysenter_flags_fixed+0xd/0x17 [ 27.535232] [ 27.536824] The buggy address belongs to the object at ffff8800b4768780 [ 27.536824] which belongs to the cache kmalloc-512 of size 512 [ 27.549445] The buggy address is located 184 bytes inside of [ 27.549445] 512-byte region [ffff8800b4768780, ffff8800b4768980) [ 27.561282] The buggy address belongs to the page: [ 29.068382] PANIC: double fault, error_code: 0x0 [ 29.073150] CPU: 0 PID: 3311 Comm: syzkaller553132 Not tainted 4.4.110-gdac1439 #13 [ 29.080905] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.090225] task: ffff8801d1c5df00 task.stack: ffff8801d1368000 [ 29.096244] RIP: 0010:[] [] dump_page_badflags+0x1a/0x250 [ 29.105076] RSP: 0018:ffff880100000000 EFLAGS: 00010086 [ 29.110491] RAX: ffff8801d1c5df00 RBX: ffffea0002d1da00 RCX: ffffffff8148f740 [ 29.117733] RDX: 0000000000000000 RSI: ffffffff838a8320 RDI: ffffea0002d1da00 [ 29.124966] RBP: ffff880100000030 R08: 0000000000000001 R09: 0000000000000000 [ 29.132201] R10: 0000000000000002 R11: fffffbfff0ad781e R12: 0000000000000000 [ 29.139435] R13: ffffffff838a8320 R14: 0000000000000000 R15: 0000000000000000 [ 29.146675] FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 [ 29.154868] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 29.160714] CR2: ffff8800fffffff8 CR3: 000000000420c000 CR4: 0000000000160670 [ 29.167950] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 29.175190] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 29.182426] Stack: [ 29.184538] [ 29.186129] Call Trace: [ 29.188676] [ 29.190701] 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 [ 29.217218] Kernel panic - not syncing: Machine halted. [ 29.222550] CPU: 0 PID: 3311 Comm: syzkaller553132 Not tainted 4.4.110-gdac1439 #13 [ 29.230316] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.239634] 0000000000000000 e020a353c791c67d ffff8801db20ce38 ffffffff81d04e3d [ 29.247582] ffffffff838367c0 ffff8801db20cf10 ffffffff83808040 ffff880100000000 [ 29.255529] 0000000000000000 ffff8801db20cf00 ffffffff814197fa 0000000041b58ab3 [ 29.263735] Call Trace: [ 29.266280] <#DF> [] dump_stack+0xc1/0x124 [ 29.272340] [] panic+0x1aa/0x388 [ 29.277326] [] ? percpu_up_read.constprop.45+0xe1/0xe1 [ 29.284216] [] ? vprintk_emit+0x242/0x850 [ 29.289981] [] ? dump_page_badflags+0x2f/0x250 [ 29.296177] [] ? vprintk_emit+0x242/0x850 [ 29.301939] [] df_debug+0x2d/0x30 [ 29.307005] [] do_double_fault+0x10b/0x210 [ 29.312859] [] double_fault+0x2d/0x40 [ 29.318278] [] ? dump_page_badflags+0x180/0x250 [ 29.324568] [] ? dump_page_badflags+0x1a/0x250 [ 29.330760] <> [ 29.334168] Dumping ftrace buffer: [ 29.337965] (ftrace buffer empty) [ 29.341645] Kernel Offset: disabled [ 29.345237] Rebooting in 86400 seconds..