[ OK ] Started Regular background program processing daemon. Starting Permit User Sessions... Starting OpenBSD Secure Shell server... [ OK ] Found device /dev/ttyS0. [ OK ] Started Permit User Sessions. [ OK ] Started System Logging Service. [ OK ] Started getty on tty2-tty6 if dbus and logind are not available. [ OK ] Started OpenBSD Secure Shell server. [ OK ] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch. [ OK ] Started Getty on tty6. [ OK ] Started Getty on tty5. [ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Getty on tty2. [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ 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 '10.128.0.92' (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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program 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: [ 33.295882] ================================================================== [ 33.303429] BUG: KASAN: use-after-free in vgem_gem_dumb_create+0x22c/0x240 [ 33.310458] Read of size 8 at addr ffff88809a734b40 by task syz-executor337/8843 [ 33.318098] [ 33.319738] CPU: 1 PID: 8843 Comm: syz-executor337 Not tainted 4.19.172-syzkaller #0 [ 33.327619] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.336974] Call Trace: [ 33.339569] dump_stack+0x1fc/0x2ef [ 33.343199] print_address_description.cold+0x54/0x219 [ 33.348465] kasan_report_error.cold+0x8a/0x1b9 [ 33.353124] ? vgem_gem_dumb_create+0x22c/0x240 [ 33.357905] __asan_report_load8_noabort+0x88/0x90 [ 33.362842] ? drm_gem_object_put_unlocked+0x40/0x180 [ 33.368026] ? vgem_gem_dumb_create+0x22c/0x240 [ 33.372679] vgem_gem_dumb_create+0x22c/0x240 [ 33.377316] drm_mode_create_dumb+0x27c/0x300 [ 33.381813] drm_ioctl_kernel+0x208/0x2a0 [ 33.385999] ? drm_mode_create_dumb+0x300/0x300 [ 33.390667] ? drm_ioctl_permit+0x210/0x210 [ 33.394981] ? __might_fault+0x192/0x1d0 [ 33.399038] drm_ioctl+0x507/0x9c0 [ 33.402564] ? drm_mode_create_dumb+0x300/0x300 [ 33.407303] ? drm_getstats+0x20/0x20 [ 33.411099] ? __fget+0x356/0x510 [ 33.414541] ? futex_exit_release+0x220/0x220 [ 33.419023] ? drm_getstats+0x20/0x20 [ 33.422811] do_vfs_ioctl+0xcdb/0x12e0 [ 33.426686] ? lock_downgrade+0x720/0x720 [ 33.430818] ? check_preemption_disabled+0x41/0x280 [ 33.435822] ? ioctl_preallocate+0x200/0x200 [ 33.440230] ? __fget+0x356/0x510 [ 33.443680] ? do_dup2+0x450/0x450 [ 33.447212] ? __se_sys_futex+0x298/0x3b0 [ 33.451373] ksys_ioctl+0x9b/0xc0 [ 33.454813] __x64_sys_ioctl+0x6f/0xb0 [ 33.458690] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 33.463278] do_syscall_64+0xf9/0x620 [ 33.467076] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.472256] RIP: 0033:0x44a5e9 [ 33.475447] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 [ 33.494344] RSP: 002b:00007f2d540e81f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 33.502045] RAX: ffffffffffffffda RBX: 00000000004cb508 RCX: 000000000044a5e9 [ 33.509311] RDX: 00000000200000c0 RSI: 00000000c02064b2 RDI: 0000000000000004 [ 33.516569] RBP: 00000000004cb500 R08: 0000000000000000 R09: 0000000000000000 [ 33.523821] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004cb50c [ 33.531074] R13: 00007ffddaf4f45f R14: 00007f2d540e8300 R15: 0000000000022000 [ 33.538338] [ 33.540406] Allocated by task 8843: [ 33.544025] kmem_cache_alloc_trace+0x12f/0x380 [ 33.548675] __vgem_gem_create+0x44/0xf0 [ 33.552720] vgem_gem_dumb_create+0xcf/0x240 [ 33.557112] drm_mode_create_dumb+0x27c/0x300 [ 33.561589] drm_ioctl_kernel+0x208/0x2a0 [ 33.566088] drm_ioctl+0x507/0x9c0 [ 33.569631] do_vfs_ioctl+0xcdb/0x12e0 [ 33.573507] ksys_ioctl+0x9b/0xc0 [ 33.576947] __x64_sys_ioctl+0x6f/0xb0 [ 33.580823] do_syscall_64+0xf9/0x620 [ 33.584612] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.589784] [ 33.591392] Freed by task 8843: [ 33.594667] kfree+0xcc/0x210 [ 33.597754] drm_gem_object_free+0x91/0x1c0 [ 33.602060] drm_gem_object_put_unlocked+0xd1/0x180 [ 33.607058] vgem_gem_dumb_create+0x10c/0x240 [ 33.611534] drm_mode_create_dumb+0x27c/0x300 [ 33.616010] drm_ioctl_kernel+0x208/0x2a0 [ 33.620138] drm_ioctl+0x507/0x9c0 [ 33.623673] do_vfs_ioctl+0xcdb/0x12e0 [ 33.627542] ksys_ioctl+0x9b/0xc0 [ 33.630979] __x64_sys_ioctl+0x6f/0xb0 [ 33.634848] do_syscall_64+0xf9/0x620 [ 33.638630] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.643809] [ 33.645421] The buggy address belongs to the object at ffff88809a734a40 [ 33.645421] which belongs to the cache kmalloc-512 of size 512 [ 33.658062] The buggy address is located 256 bytes inside of [ 33.658062] 512-byte region [ffff88809a734a40, ffff88809a734c40) [ 33.669928] The buggy address belongs to the page: [ 33.674850] page:ffffea000269cd00 count:1 mapcount:0 mapping:ffff88813bff0940 index:0x0 [ 33.682993] flags: 0xfff00000000100(slab) [ 33.687127] raw: 00fff00000000100 ffffea0002d33908 ffffea0002a44488 ffff88813bff0940 [ 33.694992] raw: 0000000000000000 ffff88809a734040 0000000100000006 0000000000000000 [ 33.702886] page dumped because: kasan: bad access detected [ 33.708573] [ 33.710182] Memory state around the buggy address: [ 33.715092] ffff88809a734a00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 33.722432] ffff88809a734a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.729771] >ffff88809a734b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.737111] ^ executing program executing program executing program executing program [ 33.742542] ffff88809a734b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.749884] ffff88809a734c00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 33.757234] ================================================================== [ 33.764572] Disabling lock debugging due to kernel taint [ 33.776899] Kernel panic - not syncing: panic_on_warn set ... [ 33.776899] [ 33.784325] CPU: 1 PID: 8843 Comm: syz-executor337 Tainted: G B 4.19.172-syzkaller #0 [ 33.793593] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.802946] Call Trace: [ 33.805537] dump_stack+0x1fc/0x2ef [ 33.809163] panic+0x26a/0x50e [ 33.812340] ? __warn_printk+0xf3/0xf3 [ 33.816206] ? preempt_schedule_common+0x45/0xc0 [ 33.820940] ? ___preempt_schedule+0x16/0x18 [ 33.825462] ? trace_hardirqs_on+0x55/0x210 [ 33.829766] kasan_end_report+0x43/0x49 [ 33.833751] kasan_report_error.cold+0xa7/0x1b9 [ 33.838431] ? vgem_gem_dumb_create+0x22c/0x240 [ 33.843216] __asan_report_load8_noabort+0x88/0x90 [ 33.848127] ? drm_gem_object_put_unlocked+0x40/0x180 [ 33.853297] ? vgem_gem_dumb_create+0x22c/0x240 [ 33.857986] vgem_gem_dumb_create+0x22c/0x240 [ 33.862464] drm_mode_create_dumb+0x27c/0x300 [ 33.866986] drm_ioctl_kernel+0x208/0x2a0 [ 33.871122] ? drm_mode_create_dumb+0x300/0x300 [ 33.875773] ? drm_ioctl_permit+0x210/0x210 [ 33.880078] ? __might_fault+0x192/0x1d0 [ 33.884116] drm_ioctl+0x507/0x9c0 [ 33.887644] ? drm_mode_create_dumb+0x300/0x300 [ 33.892298] ? drm_getstats+0x20/0x20 [ 33.896086] ? __fget+0x356/0x510 [ 33.899542] ? futex_exit_release+0x220/0x220 [ 33.904020] ? drm_getstats+0x20/0x20 [ 33.907843] do_vfs_ioctl+0xcdb/0x12e0 [ 33.911716] ? lock_downgrade+0x720/0x720 [ 33.915859] ? check_preemption_disabled+0x41/0x280 [ 33.920859] ? ioctl_preallocate+0x200/0x200 [ 33.925251] ? __fget+0x356/0x510 [ 33.928684] ? do_dup2+0x450/0x450 [ 33.932220] ? __se_sys_futex+0x298/0x3b0 [ 33.936356] ksys_ioctl+0x9b/0xc0 [ 33.939793] __x64_sys_ioctl+0x6f/0xb0 [ 33.943679] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 33.948241] do_syscall_64+0xf9/0x620 [ 33.952029] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.957205] RIP: 0033:0x44a5e9 [ 33.960376] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 [ 33.979276] RSP: 002b:00007f2d540e81f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 33.986978] RAX: ffffffffffffffda RBX: 00000000004cb508 RCX: 000000000044a5e9 [ 33.994244] RDX: 00000000200000c0 RSI: 00000000c02064b2 RDI: 0000000000000004 [ 34.001505] RBP: 00000000004cb500 R08: 0000000000000000 R09: 0000000000000000 [ 34.008753] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004cb50c [ 34.016021] R13: 00007ffddaf4f45f R14: 00007f2d540e8300 R15: 0000000000022000 [ 34.024150] Kernel Offset: disabled [ 34.027783] Rebooting in 86400 seconds..