[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Update UTMP about System Runlevel Changes. [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.10.59' (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 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 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 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 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 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 syzkaller login: [ 32.739021] ================================================================== [ 32.746744] BUG: KASAN: use-after-free in vgem_gem_dumb_create+0x200/0x210 [ 32.753813] Read of size 8 at addr ffff8880b2fd9940 by task syz-executor709/8602 [ 32.761328] [ 32.762944] CPU: 0 PID: 8602 Comm: syz-executor709 Not tainted 4.14.215-syzkaller #0 [ 32.770805] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 32.780402] Call Trace: [ 32.782986] dump_stack+0x1b2/0x283 [ 32.786611] print_address_description.cold+0x54/0x1d3 [ 32.791872] kasan_report_error.cold+0x8a/0x194 [ 32.796526] ? vgem_gem_dumb_create+0x200/0x210 [ 32.801176] __asan_report_load8_noabort+0x68/0x70 [ 32.806095] ? vgem_gem_dumb_create+0x200/0x210 [ 32.810747] vgem_gem_dumb_create+0x200/0x210 [ 32.815243] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 32.820306] ? __drm_printfn_debug+0x70/0x70 [ 32.824699] drm_ioctl_kernel+0x14c/0x200 [ 32.828832] drm_ioctl+0x419/0x870 [ 32.832360] ? __drm_printfn_debug+0x70/0x70 [ 32.836752] ? drm_getstats+0x20/0x20 [ 32.840539] ? futex_exit_release+0x220/0x220 [ 32.845110] ? __get_user_8+0x2b/0x2b [ 32.848893] ? drm_getstats+0x20/0x20 [ 32.852682] do_vfs_ioctl+0x75a/0xff0 [ 32.856510] ? ioctl_preallocate+0x1a0/0x1a0 [ 32.860902] ? lock_downgrade+0x740/0x740 [ 32.865074] ? __fget+0x225/0x360 [ 32.868511] ? do_vfs_ioctl+0xff0/0xff0 [ 32.872466] ? security_file_ioctl+0x83/0xb0 [ 32.876859] SyS_ioctl+0x7f/0xb0 [ 32.880208] ? do_vfs_ioctl+0xff0/0xff0 [ 32.884168] do_syscall_64+0x1d5/0x640 [ 32.888044] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 32.893218] RIP: 0033:0x44a509 [ 32.896391] RSP: 002b:00007fe1751bddb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 32.904079] RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 000000000044a509 [ 32.911332] RDX: 00000000200000c0 RSI: 00000000c02064b2 RDI: 0000000000000004 [ 32.918612] RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000 [ 32.925865] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c [ 32.933119] R13: 00007ffcb92b598f R14: 00007fe1751be9c0 R15: 20c49ba5e353f7cf [ 32.940408] [ 32.942050] Allocated by task 8602: [ 32.945663] kasan_kmalloc+0xeb/0x160 [ 32.949464] kmem_cache_alloc_trace+0x131/0x3d0 [ 32.954117] __vgem_gem_create+0x44/0xe0 [ 32.958158] vgem_gem_dumb_create+0xc5/0x210 [ 32.962549] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 32.967550] drm_ioctl_kernel+0x14c/0x200 [ 32.971680] drm_ioctl+0x419/0x870 [ 32.975202] do_vfs_ioctl+0x75a/0xff0 [ 32.978986] SyS_ioctl+0x7f/0xb0 [ 32.982504] do_syscall_64+0x1d5/0x640 [ 32.986377] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 32.991545] [ 32.993154] Freed by task 8602: [ 32.996415] kasan_slab_free+0xc3/0x1a0 [ 33.000372] kfree+0xc9/0x250 [ 33.003491] drm_gem_object_free+0x8f/0x150 [ 33.007795] drm_gem_object_put_unlocked+0xc3/0x160 [ 33.012794] vgem_gem_dumb_create+0xf2/0x210 [ 33.017186] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 33.022293] drm_ioctl_kernel+0x14c/0x200 [ 33.026421] drm_ioctl+0x419/0x870 [ 33.029943] do_vfs_ioctl+0x75a/0xff0 [ 33.033719] SyS_ioctl+0x7f/0xb0 [ 33.037065] do_syscall_64+0x1d5/0x640 [ 33.040932] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 33.046101] [ 33.047709] The buggy address belongs to the object at ffff8880b2fd9840 [ 33.047709] which belongs to the cache kmalloc-512 of size 512 [ 33.060343] The buggy address is located 256 bytes inside of [ 33.060343] 512-byte region [ffff8880b2fd9840, ffff8880b2fd9a40) [ 33.072198] The buggy address belongs to the page: [ 33.077107] page:ffffea0002cbf640 count:1 mapcount:0 mapping:ffff8880b2fd90c0 index:0x0 [ 33.085232] flags: 0xfff00000000100(slab) [ 33.089361] raw: 00fff00000000100 ffff8880b2fd90c0 0000000000000000 0000000100000006 [ 33.097224] raw: ffffea0002cd2160 ffffea0002b0a820 ffff88813fe80940 0000000000000000 [ 33.105085] page dumped because: kasan: bad access detected [ 33.110775] [ 33.112385] Memory state around the buggy address: [ 33.117295] ffff8880b2fd9800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 33.124697] ffff8880b2fd9880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.132049] >ffff8880b2fd9900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.139389] ^ [ 33.144820] ffff8880b2fd9980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.152159] ffff8880b2fd9a00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 33.159529] ================================================================== [ 33.166869] Disabling lock debugging due to kernel taint [ 33.173553] Kernel panic - not syncing: panic_on_warn set ... [ 33.173553] [ 33.180926] CPU: 0 PID: 8602 Comm: syz-executor709 Tainted: G B 4.14.215-syzkaller #0 [ 33.190033] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.199381] Call Trace: [ 33.201954] dump_stack+0x1b2/0x283 [ 33.205566] panic+0x1f9/0x42d [ 33.208746] ? add_taint.cold+0x16/0x16 [ 33.212703] ? ___preempt_schedule+0x16/0x18 [ 33.217102] kasan_end_report+0x43/0x49 [ 33.221061] kasan_report_error.cold+0xa7/0x194 [ 33.225713] ? vgem_gem_dumb_create+0x200/0x210 [ 33.230362] __asan_report_load8_noabort+0x68/0x70 [ 33.235271] ? vgem_gem_dumb_create+0x200/0x210 [ 33.239921] vgem_gem_dumb_create+0x200/0x210 [ 33.244399] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 33.249403] ? __drm_printfn_debug+0x70/0x70 [ 33.253796] drm_ioctl_kernel+0x14c/0x200 [ 33.257925] drm_ioctl+0x419/0x870 [ 33.261448] ? __drm_printfn_debug+0x70/0x70 [ 33.265839] ? drm_getstats+0x20/0x20 [ 33.269620] ? futex_exit_release+0x220/0x220 [ 33.274100] ? __get_user_8+0x2b/0x2b [ 33.277887] ? drm_getstats+0x20/0x20 [ 33.281674] do_vfs_ioctl+0x75a/0xff0 [ 33.285459] ? ioctl_preallocate+0x1a0/0x1a0 [ 33.289850] ? lock_downgrade+0x740/0x740 [ 33.293982] ? __fget+0x225/0x360 [ 33.297426] ? do_vfs_ioctl+0xff0/0xff0 [ 33.301381] ? security_file_ioctl+0x83/0xb0 [ 33.305773] SyS_ioctl+0x7f/0xb0 [ 33.309119] ? do_vfs_ioctl+0xff0/0xff0 [ 33.313096] do_syscall_64+0x1d5/0x640 [ 33.316974] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 33.322149] RIP: 0033:0x44a509 [ 33.325323] RSP: 002b:00007fe1751bddb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 33.333013] RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 000000000044a509 [ 33.340265] RDX: 00000000200000c0 RSI: 00000000c02064b2 RDI: 0000000000000004 [ 33.347521] RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000 [ 33.354770] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c [ 33.362022] R13: 00007ffcb92b598f R14: 00007fe1751be9c0 R15: 20c49ba5e353f7cf [ 33.370145] Kernel Offset: disabled [ 33.373841] Rebooting in 86400 seconds..