[ OK ] Started Getty on tty2. [ OK ] Started Serial Getty on ttyS0. [ OK ] Started Getty on tty1. [ 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. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.1.10' (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 syzkaller login: [ 29.875210] hrtimer: interrupt took 43073 ns executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 30.050828] ================================================================== [ 30.058411] BUG: KASAN: use-after-free in vgem_gem_dumb_create+0x200/0x210 [ 30.065436] Read of size 8 at addr ffff8880a90fe440 by task syz-executor157/8063 [ 30.073087] [ 30.074718] CPU: 1 PID: 8063 Comm: syz-executor157 Not tainted 4.14.232-syzkaller #0 [ 30.082640] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.092004] Call Trace: [ 30.094601] dump_stack+0x1b2/0x281 [ 30.098244] print_address_description.cold+0x54/0x1d3 [ 30.103531] kasan_report_error.cold+0x8a/0x191 [ 30.108206] ? vgem_gem_dumb_create+0x200/0x210 [ 30.112905] __asan_report_load8_noabort+0x68/0x70 [ 30.117848] ? vgem_gem_dumb_create+0x200/0x210 [ 30.122527] vgem_gem_dumb_create+0x200/0x210 [ 30.127031] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 30.132059] ? __drm_printfn_debug+0x70/0x70 [ 30.136471] drm_ioctl_kernel+0x14c/0x200 [ 30.140685] drm_ioctl+0x419/0x870 [ 30.144237] ? __drm_printfn_debug+0x70/0x70 [ 30.148661] ? drm_getstats+0x20/0x20 [ 30.152475] ? futex_exit_release+0x220/0x220 [ 30.156975] ? get_unused_fd_flags+0xc0/0xc0 [ 30.161394] ? __mutex_unlock_slowpath+0x75/0x770 [ 30.166337] ? wait_for_completion_io+0x10/0x10 [ 30.171019] ? _raw_spin_unlock_irqrestore+0xa3/0xe0 [ 30.176218] ? drm_getstats+0x20/0x20 [ 30.180030] do_vfs_ioctl+0x75a/0xff0 [ 30.183841] ? ioctl_preallocate+0x1a0/0x1a0 [ 30.188372] ? lock_downgrade+0x740/0x740 [ 30.192526] ? __fget+0x225/0x360 [ 30.195979] ? do_vfs_ioctl+0xff0/0xff0 [ 30.199957] ? security_file_ioctl+0x83/0xb0 [ 30.204379] SyS_ioctl+0x7f/0xb0 [ 30.207780] ? do_vfs_ioctl+0xff0/0xff0 [ 30.211768] do_syscall_64+0x1d5/0x640 [ 30.215666] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.220854] RIP: 0033:0x44a0d9 [ 30.224044] RSP: 002b:00007f7276303308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 30.231757] RAX: ffffffffffffffda RBX: 00000000004ca448 RCX: 000000000044a0d9 [ 30.239063] RDX: 00000000200000c0 RSI: 00000000c02064b2 RDI: 0000000000000007 [ 30.246343] RBP: 00000000004ca440 R08: 0000000000000000 R09: 0000000000000000 [ 30.253711] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca44c [ 30.261012] R13: 000000000049a074 R14: 6972642f7665642f R15: 0000000000022000 [ 30.268300] [ 30.269960] Allocated by task 8063: [ 30.273595] kasan_kmalloc+0xeb/0x160 [ 30.277425] kmem_cache_alloc_trace+0x131/0x3d0 [ 30.282103] __vgem_gem_create+0x44/0xe0 [ 30.286170] vgem_gem_dumb_create+0xc5/0x210 [ 30.290582] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 30.295696] drm_ioctl_kernel+0x14c/0x200 [ 30.299891] drm_ioctl+0x419/0x870 [ 30.303437] do_vfs_ioctl+0x75a/0xff0 [ 30.307441] SyS_ioctl+0x7f/0xb0 [ 30.310815] do_syscall_64+0x1d5/0x640 [ 30.314707] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.319891] [ 30.321545] Freed by task 8063: [ 30.324826] kasan_slab_free+0xc3/0x1a0 [ 30.328802] kfree+0xc9/0x250 [ 30.331943] drm_gem_object_free+0x8f/0x150 [ 30.336265] drm_gem_object_put_unlocked+0xc3/0x160 [ 30.341294] vgem_gem_dumb_create+0xf2/0x210 [ 30.345704] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 30.350725] drm_ioctl_kernel+0x14c/0x200 [ 30.354874] drm_ioctl+0x419/0x870 [ 30.358415] do_vfs_ioctl+0x75a/0xff0 [ 30.362242] SyS_ioctl+0x7f/0xb0 [ 30.365610] do_syscall_64+0x1d5/0x640 [ 30.369507] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.374710] [ 30.376341] The buggy address belongs to the object at ffff8880a90fe340 [ 30.376341] which belongs to the cache kmalloc-512 of size 512 [ 30.389008] The buggy address is located 256 bytes inside of [ 30.389008] 512-byte region [ffff8880a90fe340, ffff8880a90fe540) [ 30.400896] The buggy address belongs to the page: [ 30.405831] page:ffffea0002a43f80 count:1 mapcount:0 mapping:ffff8880a90fe0c0 index:0x0 [ 30.414028] flags: 0xfff00000000100(slab) [ 30.418480] raw: 00fff00000000100 ffff8880a90fe0c0 0000000000000000 0000000100000006 [ 30.426373] raw: ffffea0002a496e0 ffffea0002a313a0 ffff88813fe80940 0000000000000000 [ 30.434256] page dumped because: kasan: bad access detected [ 30.440050] [ 30.441673] Memory state around the buggy address: executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 30.446599] ffff8880a90fe300: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 30.453961] ffff8880a90fe380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 30.461325] >ffff8880a90fe400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 30.468709] ^ [ 30.474162] ffff8880a90fe480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 30.481523] ffff8880a90fe500: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 30.488914] ================================================================== [ 30.496272] Disabling lock debugging due to kernel taint [ 30.530502] Kernel panic - not syncing: panic_on_warn set ... [ 30.530502] [ 30.537902] CPU: 1 PID: 8063 Comm: syz-executor157 Tainted: G B 4.14.232-syzkaller #0 [ 30.546998] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.556364] Call Trace: [ 30.558960] dump_stack+0x1b2/0x281 [ 30.562621] panic+0x1f9/0x42d [ 30.565992] ? add_taint.cold+0x16/0x16 [ 30.569969] ? ___preempt_schedule+0x16/0x18 [ 30.574386] kasan_end_report+0x43/0x49 [ 30.578371] kasan_report_error.cold+0xa7/0x191 [ 30.583129] ? vgem_gem_dumb_create+0x200/0x210 [ 30.587804] __asan_report_load8_noabort+0x68/0x70 [ 30.592736] ? vgem_gem_dumb_create+0x200/0x210 [ 30.597408] vgem_gem_dumb_create+0x200/0x210 [ 30.601909] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 30.606934] ? __drm_printfn_debug+0x70/0x70 [ 30.611610] drm_ioctl_kernel+0x14c/0x200 [ 30.615768] drm_ioctl+0x419/0x870 [ 30.619311] ? __drm_printfn_debug+0x70/0x70 [ 30.623721] ? drm_getstats+0x20/0x20 [ 30.627530] ? futex_exit_release+0x220/0x220 [ 30.632026] ? get_unused_fd_flags+0xc0/0xc0 [ 30.636460] ? __mutex_unlock_slowpath+0x75/0x770 [ 30.641335] ? wait_for_completion_io+0x10/0x10 [ 30.646014] ? _raw_spin_unlock_irqrestore+0xa3/0xe0 [ 30.651128] ? drm_getstats+0x20/0x20 [ 30.655053] do_vfs_ioctl+0x75a/0xff0 [ 30.658870] ? ioctl_preallocate+0x1a0/0x1a0 [ 30.663306] ? lock_downgrade+0x740/0x740 [ 30.667475] ? __fget+0x225/0x360 [ 30.670934] ? do_vfs_ioctl+0xff0/0xff0 [ 30.674911] ? security_file_ioctl+0x83/0xb0 [ 30.679332] SyS_ioctl+0x7f/0xb0 [ 30.682693] ? do_vfs_ioctl+0xff0/0xff0 [ 30.686670] do_syscall_64+0x1d5/0x640 [ 30.690560] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.695748] RIP: 0033:0x44a0d9 [ 30.698933] RSP: 002b:00007f7276303308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 30.706750] RAX: ffffffffffffffda RBX: 00000000004ca448 RCX: 000000000044a0d9 [ 30.714019] RDX: 00000000200000c0 RSI: 00000000c02064b2 RDI: 0000000000000007 [ 30.721389] RBP: 00000000004ca440 R08: 0000000000000000 R09: 0000000000000000 [ 30.728659] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca44c [ 30.736018] R13: 000000000049a074 R14: 6972642f7665642f R15: 0000000000022000 [ 30.743907] Kernel Offset: disabled [ 30.747524] Rebooting in 86400 seconds..