[....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 39.363168] random: sshd: uninitialized urandom read (32 bytes read) [ 39.778932] kauditd_printk_skb: 9 callbacks suppressed [ 39.778940] audit: type=1400 audit(1570322528.228:35): avc: denied { map } for pid=6780 comm="bash" path="/bin/bash" dev="sda1" ino=1457 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 [ 39.821043] random: sshd: uninitialized urandom read (32 bytes read) [ 40.324129] random: sshd: uninitialized urandom read (32 bytes read) [ 54.159922] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.222' (ECDSA) to the list of known hosts. [ 59.691353] random: sshd: uninitialized urandom read (32 bytes read) executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 59.811637] audit: type=1400 audit(1570322548.268:36): avc: denied { map } for pid=6792 comm="syz-executor279" path="/root/syz-executor279784374" dev="sda1" ino=16482 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 60.036991] ================================================================== [ 60.044640] BUG: KASAN: use-after-free in __vb2_perform_fileio+0xddf/0xeb0 [ 60.051640] Read of size 4 at addr ffff8880a121ac5c by task syz-executor279/6996 [ 60.059575] [ 60.061203] CPU: 0 PID: 6996 Comm: syz-executor279 Not tainted 4.14.147 #0 [ 60.068206] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 60.077625] Call Trace: [ 60.080219] dump_stack+0x138/0x197 [ 60.083839] ? __vb2_perform_fileio+0xddf/0xeb0 [ 60.088490] print_address_description.cold+0x7c/0x1dc [ 60.093763] ? __vb2_perform_fileio+0xddf/0xeb0 [ 60.098414] kasan_report.cold+0xa9/0x2af [ 60.102549] __asan_report_load4_noabort+0x14/0x20 [ 60.107475] __vb2_perform_fileio+0xddf/0xeb0 [ 60.111955] ? vb2_core_poll+0x600/0x600 [ 60.115998] ? fsnotify+0x11e0/0x11e0 [ 60.119790] vb2_read+0x3b/0x50 [ 60.123063] vb2_fop_read+0x1f5/0x3e0 [ 60.126937] ? vb2_fop_write+0x3e0/0x3e0 [ 60.131048] v4l2_read+0x1a9/0x200 [ 60.134569] do_iter_read+0x3e2/0x5b0 [ 60.138351] vfs_readv+0xd3/0x130 [ 60.141788] ? compat_rw_copy_check_uvector+0x310/0x310 [ 60.147135] ? __fget+0x237/0x370 [ 60.150572] ? __fget_light+0x172/0x1f0 [ 60.154525] do_readv+0x10a/0x2d0 [ 60.157982] ? vfs_readv+0x130/0x130 [ 60.161683] ? do_futex+0x19e0/0x19e0 [ 60.165470] ? do_preadv+0x200/0x200 [ 60.169171] SyS_readv+0x28/0x30 [ 60.172518] do_syscall_64+0x1e8/0x640 [ 60.176385] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 60.181253] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 60.186439] RIP: 0033:0x44a439 [ 60.189609] RSP: 002b:00007f274b9eadb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000013 [ 60.197302] RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 000000000044a439 [ 60.204565] RDX: 0000000000000001 RSI: 0000000020000240 RDI: 0000000000000006 [ 60.211817] RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000 [ 60.219164] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c [ 60.226416] R13: 00007ffecee4f4bf R14: 00007f274b9eb9c0 R15: 0000000000000000 [ 60.233675] [ 60.235286] Allocated by task 6996: [ 60.238898] save_stack_trace+0x16/0x20 [ 60.242851] save_stack+0x45/0xd0 [ 60.246282] kasan_kmalloc+0xce/0xf0 [ 60.249976] kmem_cache_alloc_trace+0x152/0x790 [ 60.254624] __vb2_init_fileio+0x182/0xa90 [ 60.258839] __vb2_perform_fileio+0x9f0/0xeb0 [ 60.263311] vb2_read+0x3b/0x50 [ 60.266569] vb2_fop_read+0x1f5/0x3e0 [ 60.270349] v4l2_read+0x1a9/0x200 [ 60.273870] do_iter_read+0x3e2/0x5b0 [ 60.277654] vfs_readv+0xd3/0x130 [ 60.281354] do_readv+0x10a/0x2d0 [ 60.284784] SyS_readv+0x28/0x30 [ 60.288136] do_syscall_64+0x1e8/0x640 [ 60.292003] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 60.297168] [ 60.298776] Freed by task 6989: [ 60.302034] save_stack_trace+0x16/0x20 [ 60.305991] save_stack+0x45/0xd0 [ 60.309428] kasan_slab_free+0x75/0xc0 [ 60.313292] kfree+0xcc/0x270 [ 60.316378] __vb2_cleanup_fileio+0xfc/0x150 [ 60.320783] vb2_core_queue_release+0x1d/0x80 [ 60.325257] _vb2_fop_release+0x1cf/0x2a0 [ 60.329384] vb2_fop_release+0x75/0xc0 [ 60.333254] vivid_fop_release+0x180/0x3f0 [ 60.337474] v4l2_release+0xf9/0x190 [ 60.341169] __fput+0x275/0x7a0 [ 60.344424] ____fput+0x16/0x20 [ 60.347688] task_work_run+0x114/0x190 [ 60.351555] do_exit+0x7df/0x2c10 [ 60.354995] do_group_exit+0x111/0x330 [ 60.358872] get_signal+0x381/0x1cd0 [ 60.362568] do_signal+0x86/0x19a0 [ 60.366085] exit_to_usermode_loop+0x15c/0x220 [ 60.370648] do_syscall_64+0x4bc/0x640 [ 60.374517] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 60.379685] [ 60.381298] The buggy address belongs to the object at ffff8880a121a940 [ 60.381298] which belongs to the cache kmalloc-1024 of size 1024 [ 60.394108] The buggy address is located 796 bytes inside of [ 60.394108] 1024-byte region [ffff8880a121a940, ffff8880a121ad40) [ 60.406049] The buggy address belongs to the page: [ 60.410960] page:ffffea0002848680 count:1 mapcount:0 mapping:ffff8880a121a040 index:0x0 compound_mapcount: 0 [ 60.420913] flags: 0x1fffc0000008100(slab|head) [ 60.425584] raw: 01fffc0000008100 ffff8880a121a040 0000000000000000 0000000100000007 [ 60.433453] raw: ffffea00021d2a20 ffffea0002234920 ffff8880aa800ac0 0000000000000000 [ 60.441319] page dumped because: kasan: bad access detected [ 60.449889] [ 60.451496] Memory state around the buggy address: [ 60.457203] ffff8880a121ab00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 60.464546] ffff8880a121ab80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 60.471894] >ffff8880a121ac00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 60.479242] ^ [ 60.485569] ffff8880a121ac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 60.492906] ffff8880a121ad00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 60.500270] ================================================================== [ 60.507605] Disabling lock debugging due to kernel taint [ 60.514668] Kernel panic - not syncing: panic_on_warn set ... [ 60.514668] [ 60.522045] CPU: 0 PID: 6996 Comm: syz-executor279 Tainted: G B 4.14.147 #0 [ 60.530265] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 60.539607] Call Trace: [ 60.542184] dump_stack+0x138/0x197 [ 60.545790] ? __vb2_perform_fileio+0xddf/0xeb0 [ 60.550438] panic+0x1f2/0x426 [ 60.553606] ? add_taint.cold+0x16/0x16 [ 60.559209] ? ___preempt_schedule+0x16/0x18 [ 60.563595] kasan_end_report+0x47/0x4f [ 60.567545] kasan_report.cold+0x130/0x2af [ 60.571758] __asan_report_load4_noabort+0x14/0x20 [ 60.576786] __vb2_perform_fileio+0xddf/0xeb0 [ 60.581283] ? vb2_core_poll+0x600/0x600 [ 60.585329] ? fsnotify+0x11e0/0x11e0 [ 60.589110] vb2_read+0x3b/0x50 [ 60.592367] vb2_fop_read+0x1f5/0x3e0 [ 60.596142] ? vb2_fop_write+0x3e0/0x3e0 [ 60.600178] v4l2_read+0x1a9/0x200 [ 60.603709] do_iter_read+0x3e2/0x5b0 [ 60.607486] vfs_readv+0xd3/0x130 [ 60.610917] ? compat_rw_copy_check_uvector+0x310/0x310 [ 60.616267] ? __fget+0x237/0x370 [ 60.619697] ? __fget_light+0x172/0x1f0 [ 60.623647] do_readv+0x10a/0x2d0 [ 60.627163] ? vfs_readv+0x130/0x130 [ 60.630855] ? do_futex+0x19e0/0x19e0 [ 60.634633] ? do_preadv+0x200/0x200 [ 60.638332] SyS_readv+0x28/0x30 [ 60.641705] do_syscall_64+0x1e8/0x640 [ 60.645566] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 60.650387] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 60.655552] RIP: 0033:0x44a439 [ 60.658760] RSP: 002b:00007f274b9eadb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000013 [ 60.666468] RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 000000000044a439 [ 60.673728] RDX: 0000000000000001 RSI: 0000000020000240 RDI: 0000000000000006 [ 60.680975] RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000 [ 60.688246] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c [ 60.695495] R13: 00007ffecee4f4bf R14: 00007f274b9eb9c0 R15: 0000000000000000 [ 60.704508] Kernel Offset: disabled [ 60.708168] Rebooting in 86400 seconds..