[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.48' (ECDSA) to the list of known hosts. 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 syzkaller login: [ 28.089003] ================================================================== [ 28.096509] BUG: KASAN: use-after-free in __vb2_perform_fileio+0xce9/0xda0 [ 28.103504] Read of size 4 at addr ffff88809ced87dc by task syz-executor359/7973 [ 28.111014] [ 28.112626] CPU: 0 PID: 7973 Comm: syz-executor359 Not tainted 4.14.282-syzkaller #0 [ 28.120480] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.129813] Call Trace: [ 28.132383] dump_stack+0x1b2/0x281 [ 28.135987] print_address_description.cold+0x54/0x1d3 [ 28.141240] kasan_report_error.cold+0x8a/0x191 [ 28.145888] ? __vb2_perform_fileio+0xce9/0xda0 [ 28.150536] __asan_report_load4_noabort+0x68/0x70 [ 28.155441] ? __vb2_perform_fileio+0xce9/0xda0 [ 28.160180] __vb2_perform_fileio+0xce9/0xda0 [ 28.164655] ? __vb2_init_fileio+0xa90/0xa90 [ 28.169040] ? common_file_perm+0x3ee/0x580 [ 28.173354] vb2_fop_read+0x1ef/0x3d0 [ 28.177184] ? vb2_fop_write+0x3d0/0x3d0 [ 28.181222] v4l2_read+0x19a/0x200 [ 28.184738] do_iter_read+0x3eb/0x5b0 [ 28.188516] ? finish_mkwrite_fault+0x5e0/0x5e0 [ 28.193160] vfs_readv+0xc8/0x120 [ 28.196591] ? compat_rw_copy_check_uvector+0x320/0x320 [ 28.201952] ? __do_page_fault+0x571/0xad0 [ 28.206165] ? lock_downgrade+0x740/0x740 [ 28.210290] SyS_preadv+0x15a/0x200 [ 28.213891] ? SyS_writev+0x30/0x30 [ 28.217549] ? __do_page_fault+0x159/0xad0 [ 28.221766] ? do_syscall_64+0x4c/0x640 [ 28.225719] ? SyS_writev+0x30/0x30 [ 28.229365] do_syscall_64+0x1d5/0x640 [ 28.233235] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 28.238405] RIP: 0033:0x7ff4d304c439 [ 28.242092] RSP: 002b:00007fffd8faa818 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 [ 28.249777] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00007ff4d304c439 [ 28.257024] RDX: 0000000000000001 RSI: 0000000020000600 RDI: 0000000000000003 [ 28.264273] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 28.271532] R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000006cdc [ 28.278782] R13: 00007fffd8faa82c R14: 00007fffd8faa840 R15: 00007fffd8faa830 [ 28.286035] [ 28.287641] Allocated by task 7973: [ 28.291248] kasan_kmalloc+0xeb/0x160 [ 28.295063] kmem_cache_alloc_trace+0x131/0x3d0 [ 28.299722] __vb2_init_fileio+0x17f/0xa90 [ 28.303934] __vb2_perform_fileio+0x993/0xda0 [ 28.308497] vb2_fop_read+0x1ef/0x3d0 [ 28.312269] v4l2_read+0x19a/0x200 [ 28.315780] do_iter_read+0x3eb/0x5b0 [ 28.319553] vfs_readv+0xc8/0x120 [ 28.322985] SyS_preadv+0x15a/0x200 [ 28.326634] do_syscall_64+0x1d5/0x640 [ 28.330498] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 28.335658] [ 28.337287] Freed by task 7974: [ 28.340542] kasan_slab_free+0xc3/0x1a0 [ 28.344489] kfree+0xc9/0x250 [ 28.347572] __vb2_cleanup_fileio+0xf5/0x150 [ 28.351953] vb2_core_queue_release+0x17/0x70 [ 28.356424] _vb2_fop_release+0x1c1/0x280 [ 28.360557] vivid_fop_release+0x17d/0x6c0 [ 28.364769] v4l2_release+0xf4/0x190 [ 28.368458] __fput+0x25f/0x7a0 [ 28.371716] task_work_run+0x11f/0x190 [ 28.375579] do_exit+0xa44/0x2850 [ 28.379020] do_group_exit+0x100/0x2e0 [ 28.382879] SyS_exit_group+0x19/0x20 [ 28.386653] do_syscall_64+0x1d5/0x640 [ 28.390512] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 28.395675] [ 28.397280] The buggy address belongs to the object at ffff88809ced84c0 [ 28.397280] which belongs to the cache kmalloc-1024 of size 1024 [ 28.410091] The buggy address is located 796 bytes inside of [ 28.410091] 1024-byte region [ffff88809ced84c0, ffff88809ced88c0) [ 28.422023] The buggy address belongs to the page: [ 28.426925] page:ffffea000273b600 count:1 mapcount:0 mapping:ffff88809ced8040 index:0x0 compound_mapcount: 0 [ 28.436864] flags: 0xfff00000008100(slab|head) [ 28.441420] raw: 00fff00000008100 ffff88809ced8040 0000000000000000 0000000100000007 [ 28.449282] raw: ffffea00026b3e20 ffffea00026d4a20 ffff88813fe74ac0 0000000000000000 [ 28.457140] page dumped because: kasan: bad access detected [ 28.462818] [ 28.464420] Memory state around the buggy address: [ 28.469333] ffff88809ced8680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.476667] ffff88809ced8700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb executing program [ 28.484000] >ffff88809ced8780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.491340] ^ [ 28.497543] ffff88809ced8800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 28.504879] ffff88809ced8880: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 28.512208] ================================================================== [ 28.519536] Disabling lock debugging due to kernel taint [ 28.535679] Kernel panic - not syncing: panic_on_warn set ... [ 28.535679] [ 28.543056] CPU: 1 PID: 7973 Comm: syz-executor359 Tainted: G B 4.14.282-syzkaller #0 [ 28.552132] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.561458] Call Trace: [ 28.564019] dump_stack+0x1b2/0x281 [ 28.567621] panic+0x1f9/0x42d [ 28.570786] ? add_taint.cold+0x16/0x16 [ 28.574734] ? ___preempt_schedule+0x16/0x18 [ 28.579127] kasan_end_report+0x43/0x49 [ 28.583071] kasan_report_error.cold+0xa7/0x191 [ 28.587723] ? __vb2_perform_fileio+0xce9/0xda0 [ 28.592362] __asan_report_load4_noabort+0x68/0x70 [ 28.597265] ? __vb2_perform_fileio+0xce9/0xda0 [ 28.601907] __vb2_perform_fileio+0xce9/0xda0 [ 28.606376] ? __vb2_init_fileio+0xa90/0xa90 [ 28.610758] ? common_file_perm+0x3ee/0x580 [ 28.615054] vb2_fop_read+0x1ef/0x3d0 [ 28.618825] ? vb2_fop_write+0x3d0/0x3d0 [ 28.622859] v4l2_read+0x19a/0x200 [ 28.626374] do_iter_read+0x3eb/0x5b0 [ 28.630147] ? finish_mkwrite_fault+0x5e0/0x5e0 [ 28.634790] vfs_readv+0xc8/0x120 [ 28.638217] ? compat_rw_copy_check_uvector+0x320/0x320 [ 28.643563] ? __do_page_fault+0x571/0xad0 [ 28.647772] ? lock_downgrade+0x740/0x740 [ 28.651897] SyS_preadv+0x15a/0x200 [ 28.655496] ? SyS_writev+0x30/0x30 [ 28.659097] ? __do_page_fault+0x159/0xad0 [ 28.663301] ? do_syscall_64+0x4c/0x640 [ 28.667245] ? SyS_writev+0x30/0x30 [ 28.670843] do_syscall_64+0x1d5/0x640 [ 28.674704] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 28.679872] RIP: 0033:0x7ff4d304c439 [ 28.683553] RSP: 002b:00007fffd8faa818 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 [ 28.691230] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00007ff4d304c439 [ 28.698473] RDX: 0000000000000001 RSI: 0000000020000600 RDI: 0000000000000003 [ 28.705716] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 28.712957] R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000006cdc [ 28.720197] R13: 00007fffd8faa82c R14: 00007fffd8faa840 R15: 00007fffd8faa830 [ 28.727610] Kernel Offset: disabled [ 28.731212] Rebooting in 86400 seconds..