[ 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 '10.128.0.93' (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 syzkaller login: [ 29.895943] ================================================================== [ 29.903454] BUG: KASAN: use-after-free in vgem_gem_dumb_create+0x200/0x210 [ 29.910472] Read of size 8 at addr ffff88809f929940 by task syz-executor707/8448 [ 29.918036] [ 29.919669] CPU: 1 PID: 8448 Comm: syz-executor707 Not tainted 4.14.237-syzkaller #0 [ 29.927547] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.936899] Call Trace: [ 29.939481] dump_stack+0x1b2/0x281 executing program executing program [ 29.943112] print_address_description.cold+0x54/0x1d3 [ 29.948497] kasan_report_error.cold+0x8a/0x191 [ 29.953208] ? vgem_gem_dumb_create+0x200/0x210 [ 29.957866] __asan_report_load8_noabort+0x68/0x70 [ 29.962802] ? vgem_gem_dumb_create+0x200/0x210 [ 29.967484] vgem_gem_dumb_create+0x200/0x210 [ 29.971982] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 29.977078] ? __drm_printfn_debug+0x70/0x70 [ 29.981516] drm_ioctl_kernel+0x14c/0x200 [ 29.985654] drm_ioctl+0x419/0x870 [ 29.989268] ? __drm_printfn_debug+0x70/0x70 [ 29.993657] ? drm_getstats+0x20/0x20 [ 29.997462] ? futex_exit_release+0x220/0x220 [ 30.001944] ? __get_user_8+0x2b/0x2b [ 30.005747] ? drm_getstats+0x20/0x20 [ 30.009556] do_vfs_ioctl+0x75a/0xff0 [ 30.013338] ? ioctl_preallocate+0x1a0/0x1a0 [ 30.017843] ? lock_downgrade+0x740/0x740 [ 30.021983] ? __fget+0x225/0x360 [ 30.025423] ? do_vfs_ioctl+0xff0/0xff0 [ 30.029407] ? security_file_ioctl+0x83/0xb0 [ 30.033805] SyS_ioctl+0x7f/0xb0 [ 30.037162] ? do_vfs_ioctl+0xff0/0xff0 [ 30.041126] do_syscall_64+0x1d5/0x640 [ 30.045008] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.050190] RIP: 0033:0x449fb9 [ 30.053366] RSP: 002b:00007ffa72d37308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 30.061067] RAX: ffffffffffffffda RBX: 00000000004ca448 RCX: 0000000000449fb9 [ 30.068333] RDX: 00000000200000c0 RSI: 00000000c02064b2 RDI: 0000000000000005 [ 30.075601] RBP: 00000000004ca440 R08: 0000000000000000 R09: 0000000000000000 [ 30.082864] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca44c [ 30.090129] R13: 000000000049a074 R14: 6972642f7665642f R15: 0000000000022000 [ 30.097398] [ 30.099011] Allocated by task 8448: [ 30.102636] kasan_kmalloc+0xeb/0x160 [ 30.106430] kmem_cache_alloc_trace+0x131/0x3d0 [ 30.111107] __vgem_gem_create+0x44/0xe0 [ 30.115159] vgem_gem_dumb_create+0xc5/0x210 [ 30.119568] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 30.124583] drm_ioctl_kernel+0x14c/0x200 [ 30.128740] drm_ioctl+0x419/0x870 [ 30.132274] do_vfs_ioctl+0x75a/0xff0 [ 30.136063] SyS_ioctl+0x7f/0xb0 [ 30.139420] do_syscall_64+0x1d5/0x640 [ 30.143301] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.148477] [ 30.150090] Freed by task 8448: [ 30.153362] kasan_slab_free+0xc3/0x1a0 [ 30.157327] kfree+0xc9/0x250 [ 30.160439] drm_gem_object_free+0x8f/0x150 [ 30.164750] drm_gem_object_put_unlocked+0xc3/0x160 [ 30.169783] vgem_gem_dumb_create+0xf2/0x210 [ 30.174179] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 30.179186] drm_ioctl_kernel+0x14c/0x200 [ 30.183320] drm_ioctl+0x419/0x870 [ 30.186854] do_vfs_ioctl+0x75a/0xff0 [ 30.190745] SyS_ioctl+0x7f/0xb0 [ 30.194102] do_syscall_64+0x1d5/0x640 [ 30.197990] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.203184] [ 30.204824] The buggy address belongs to the object at ffff88809f929840 [ 30.204824] which belongs to the cache kmalloc-512 of size 512 [ 30.217482] The buggy address is located 256 bytes inside of [ 30.217482] 512-byte region [ffff88809f929840, ffff88809f929a40) [ 30.229351] The buggy address belongs to the page: [ 30.234277] page:ffffea00027e4a40 count:1 mapcount:0 mapping:ffff88809f9290c0 index:0x0 [ 30.242417] flags: 0xfff00000000100(slab) [ 30.246558] raw: 00fff00000000100 ffff88809f9290c0 0000000000000000 0000000100000006 [ 30.254430] raw: ffffea0002c5fba0 ffffea00027969a0 ffff88813fe80940 0000000000000000 [ 30.262301] page dumped because: kasan: bad access detected [ 30.267995] [ 30.269604] Memory state around the buggy address: [ 30.274519] ffff88809f929800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 30.281875] ffff88809f929880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 30.289251] >ffff88809f929900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb executing program executing program executing program executing program executing program executing program [ 30.296637] ^ [ 30.302096] ffff88809f929980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 30.309466] ffff88809f929a00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 30.316828] ================================================================== [ 30.324192] Disabling lock debugging due to kernel taint executing program [ 30.349145] Kernel panic - not syncing: panic_on_warn set ... [ 30.349145] [ 30.356539] CPU: 1 PID: 8448 Comm: syz-executor707 Tainted: G B 4.14.237-syzkaller #0 [ 30.365630] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.374975] Call Trace: [ 30.377546] dump_stack+0x1b2/0x281 [ 30.381158] panic+0x1f9/0x42d [ 30.384467] ? add_taint.cold+0x16/0x16 [ 30.388545] ? ___preempt_schedule+0x16/0x18 [ 30.392981] kasan_end_report+0x43/0x49 [ 30.396941] kasan_report_error.cold+0xa7/0x191 [ 30.401598] ? vgem_gem_dumb_create+0x200/0x210 [ 30.406429] __asan_report_load8_noabort+0x68/0x70 [ 30.411370] ? vgem_gem_dumb_create+0x200/0x210 [ 30.416019] vgem_gem_dumb_create+0x200/0x210 [ 30.420549] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 30.425543] ? __drm_printfn_debug+0x70/0x70 [ 30.429934] drm_ioctl_kernel+0x14c/0x200 [ 30.434087] drm_ioctl+0x419/0x870 [ 30.437636] ? __drm_printfn_debug+0x70/0x70 [ 30.442046] ? drm_getstats+0x20/0x20 [ 30.445831] ? futex_exit_release+0x220/0x220 [ 30.450310] ? __get_user_8+0x2b/0x2b [ 30.454114] ? drm_getstats+0x20/0x20 [ 30.458136] do_vfs_ioctl+0x75a/0xff0 [ 30.461949] ? ioctl_preallocate+0x1a0/0x1a0 [ 30.466431] ? lock_downgrade+0x740/0x740 [ 30.470566] ? __fget+0x225/0x360 [ 30.474434] ? do_vfs_ioctl+0xff0/0xff0 [ 30.478490] ? security_file_ioctl+0x83/0xb0 [ 30.482878] SyS_ioctl+0x7f/0xb0 [ 30.486224] ? do_vfs_ioctl+0xff0/0xff0 [ 30.490185] do_syscall_64+0x1d5/0x640 [ 30.494077] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.499271] RIP: 0033:0x449fb9 [ 30.502441] RSP: 002b:00007ffa72d37308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 30.510127] RAX: ffffffffffffffda RBX: 00000000004ca448 RCX: 0000000000449fb9 [ 30.517504] RDX: 00000000200000c0 RSI: 00000000c02064b2 RDI: 0000000000000005 [ 30.524767] RBP: 00000000004ca440 R08: 0000000000000000 R09: 0000000000000000 [ 30.532103] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca44c [ 30.539398] R13: 000000000049a074 R14: 6972642f7665642f R15: 0000000000022000 [ 30.547331] Kernel Offset: disabled [ 30.550947] Rebooting in 86400 seconds..