[ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.10.36' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program syzkaller login: [ 84.574484] audit: type=1400 audit(1602586354.063:8): avc: denied { execmem } for pid=6347 comm="syz-executor628" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process 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 [ 85.539037] ================================================================== [ 85.546542] BUG: KASAN: use-after-free in __vb2_perform_fileio+0xce9/0xda0 [ 85.553607] Read of size 4 at addr ffff8880978d155c by task syz-executor628/6403 [ 85.561270] [ 85.562896] CPU: 0 PID: 6403 Comm: syz-executor628 Not tainted 4.14.198-syzkaller #0 [ 85.570775] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 85.580113] Call Trace: [ 85.582703] dump_stack+0x1b2/0x283 [ 85.586319] print_address_description.cold+0x54/0x1d3 [ 85.591586] kasan_report_error.cold+0x8a/0x194 [ 85.596249] ? __vb2_perform_fileio+0xce9/0xda0 [ 85.600928] __asan_report_load4_noabort+0x68/0x70 [ 85.606052] ? __vb2_perform_fileio+0xce9/0xda0 [ 85.610713] __vb2_perform_fileio+0xce9/0xda0 [ 85.615197] ? __vb2_init_fileio+0xa90/0xa90 [ 85.619609] ? __lock_acquire+0x5fc/0x3f20 [ 85.623833] vb2_fop_read+0x1ef/0x3d0 [ 85.627663] ? vb2_fop_write+0x3d0/0x3d0 [ 85.631808] v4l2_read+0x19a/0x200 [ 85.635348] __vfs_read+0xe4/0x620 [ 85.638897] ? v4l2_write+0x200/0x200 [ 85.642813] ? vfs_copy_file_range+0x9b0/0x9b0 [ 85.647412] ? avc_policy_seqno+0x5/0x10 [ 85.651458] ? selinux_file_permission+0x7e/0x530 [ 85.656287] ? security_file_permission+0x82/0x1e0 [ 85.661220] ? rw_verify_area+0xe1/0x2a0 [ 85.665262] vfs_read+0x139/0x340 [ 85.668715] SyS_read+0xf2/0x210 [ 85.672077] ? kernel_write+0x110/0x110 [ 85.676045] ? __do_page_fault+0x19a/0xb50 [ 85.680281] ? do_syscall_64+0x4c/0x640 [ 85.684242] ? kernel_write+0x110/0x110 [ 85.688315] do_syscall_64+0x1d5/0x640 [ 85.692299] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 85.697475] RIP: 0033:0x444fd9 [ 85.700672] RSP: 002b:00007fffc80059b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 85.708362] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000444fd9 [ 85.715643] RDX: 00000000000000b3 RSI: 0000000020000080 RDI: 0000000000000003 [ 85.722910] RBP: 0000000000014d51 R08: 0000000000000004 R09: 00000000004002e0 [ 85.730204] R10: 000000000000000f R11: 0000000000000246 R12: 00000000004020f0 [ 85.737458] R13: 0000000000402180 R14: 0000000000000000 R15: 0000000000000000 [ 85.744742] [ 85.746707] Allocated by task 6403: [ 85.750644] kasan_kmalloc+0xeb/0x160 [ 85.755020] kmem_cache_alloc_trace+0x131/0x3d0 [ 85.759703] __vb2_init_fileio+0x17f/0xa90 [ 85.764100] __vb2_perform_fileio+0x993/0xda0 [ 85.768599] vb2_fop_read+0x1ef/0x3d0 [ 85.772399] v4l2_read+0x19a/0x200 [ 85.776043] __vfs_read+0xe4/0x620 [ 85.779708] vfs_read+0x139/0x340 [ 85.783435] SyS_read+0xf2/0x210 [ 85.786946] do_syscall_64+0x1d5/0x640 [ 85.790820] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 85.796250] [ 85.797863] Freed by task 6406: [ 85.801301] kasan_slab_free+0xc3/0x1a0 [ 85.805414] kfree+0xc9/0x250 [ 85.809562] __vb2_cleanup_fileio+0xf5/0x150 [ 85.817129] vb2_core_queue_release+0x17/0x70 [ 85.821920] _vb2_fop_release+0x1c1/0x280 [ 85.834418] vivid_fop_release+0x17d/0x6b6 [ 85.838656] v4l2_release+0xf4/0x190 [ 85.842483] __fput+0x25f/0x7a0 [ 85.845751] task_work_run+0x11f/0x190 [ 85.849628] do_exit+0xa08/0x27f0 [ 85.853073] do_group_exit+0x100/0x2e0 [ 85.856984] SyS_exit_group+0x19/0x20 [ 85.860784] do_syscall_64+0x1d5/0x640 [ 85.864658] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 85.869862] [ 85.871507] The buggy address belongs to the object at ffff8880978d1240 [ 85.871507] which belongs to the cache kmalloc-1024 of size 1024 [ 85.884352] The buggy address is located 796 bytes inside of [ 85.884352] 1024-byte region [ffff8880978d1240, ffff8880978d1640) [ 85.898165] The buggy address belongs to the page: [ 85.903082] page:ffffea00025e3400 count:1 mapcount:0 mapping:ffff8880978d0040 index:0xffff8880978d0040 compound_mapcount: 0 [ 85.914431] flags: 0xfffe0000008100(slab|head) [ 85.918996] raw: 00fffe0000008100 ffff8880978d0040 ffff8880978d0040 0000000100000006 [ 85.926879] raw: ffffea0002770620 ffffea00029e7220 ffff88812fe50ac0 0000000000000000 [ 85.934754] page dumped because: kasan: bad access detected [ 85.940529] [ 85.942135] Memory state around the buggy address: [ 85.947048] ffff8880978d1400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 85.954389] ffff8880978d1480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 85.961925] >ffff8880978d1500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 85.972258] ^ [ 85.979259] ffff8880978d1580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 85.988609] ffff8880978d1600: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 85.998510] ================================================================== [ 86.007516] Disabling lock debugging due to kernel taint [ 86.013391] Kernel panic - not syncing: panic_on_warn set ... [ 86.013391] [ 86.022808] CPU: 0 PID: 6403 Comm: syz-executor628 Tainted: G B 4.14.198-syzkaller #0 [ 86.033500] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 86.044233] Call Trace: [ 86.050761] dump_stack+0x1b2/0x283 [ 86.092226] panic+0x1f9/0x42d [ 86.114718] ? add_taint.cold+0x16/0x16 [ 86.128545] ? ___preempt_schedule+0x16/0x18 [ 86.133035] kasan_end_report+0x43/0x49 [ 86.137256] kasan_report_error.cold+0xa7/0x194 [ 86.141915] ? __vb2_perform_fileio+0xce9/0xda0 [ 86.146647] __asan_report_load4_noabort+0x68/0x70 [ 86.151753] ? __vb2_perform_fileio+0xce9/0xda0 [ 86.156403] __vb2_perform_fileio+0xce9/0xda0 [ 86.160908] ? __vb2_init_fileio+0xa90/0xa90 [ 86.165302] ? __lock_acquire+0x5fc/0x3f20 [ 86.169535] vb2_fop_read+0x1ef/0x3d0 [ 86.173340] ? vb2_fop_write+0x3d0/0x3d0 [ 86.177450] v4l2_read+0x19a/0x200 [ 86.180976] __vfs_read+0xe4/0x620 [ 86.184516] ? v4l2_write+0x200/0x200 [ 86.188307] ? vfs_copy_file_range+0x9b0/0x9b0 [ 86.192959] ? avc_policy_seqno+0x5/0x10 [ 86.197000] ? selinux_file_permission+0x7e/0x530 [ 86.201843] ? security_file_permission+0x82/0x1e0 [ 86.206779] ? rw_verify_area+0xe1/0x2a0 [ 86.210834] vfs_read+0x139/0x340 [ 86.214393] SyS_read+0xf2/0x210 [ 86.218129] ? kernel_write+0x110/0x110 [ 86.222081] ? __do_page_fault+0x19a/0xb50 [ 86.226313] ? do_syscall_64+0x4c/0x640 [ 86.230289] ? kernel_write+0x110/0x110 [ 86.234259] do_syscall_64+0x1d5/0x640 [ 86.238161] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 86.243343] RIP: 0033:0x444fd9 [ 86.246515] RSP: 002b:00007fffc80059b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 86.254725] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000444fd9 [ 86.263816] RDX: 00000000000000b3 RSI: 0000000020000080 RDI: 0000000000000003 [ 86.271763] RBP: 0000000000014d51 R08: 0000000000000004 R09: 00000000004002e0 [ 86.279190] R10: 000000000000000f R11: 0000000000000246 R12: 00000000004020f0 [ 86.286975] R13: 0000000000402180 R14: 0000000000000000 R15: 0000000000000000 [ 86.299427] Kernel Offset: disabled [ 86.303131] Rebooting in 86400 seconds..