[ 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 '10.128.0.103' (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 executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 34.800243] ================================================================== [ 34.807695] BUG: KASAN: use-after-free in vgem_gem_dumb_create+0x22c/0x240 [ 34.814691] Read of size 8 at addr ffff8880aaa24380 by task syz-executor192/8861 [ 34.822201] [ 34.823816] CPU: 1 PID: 8861 Comm: syz-executor192 Not tainted 4.19.211-syzkaller #0 [ 34.831759] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 34.841099] Call Trace: [ 34.843677] dump_stack+0x1fc/0x2ef [ 34.847295] print_address_description.cold+0x54/0x219 [ 34.852562] kasan_report_error.cold+0x8a/0x1b9 [ 34.857216] ? vgem_gem_dumb_create+0x22c/0x240 [ 34.861869] __asan_report_load8_noabort+0x88/0x90 [ 34.866784] ? drm_gem_object_put_unlocked+0xa0/0x180 [ 34.871957] ? vgem_gem_dumb_create+0x22c/0x240 [ 34.876604] vgem_gem_dumb_create+0x22c/0x240 [ 34.881084] drm_mode_create_dumb+0x27c/0x300 [ 34.885566] drm_ioctl_kernel+0x208/0x2a0 [ 34.889696] ? drm_mode_create_dumb+0x300/0x300 [ 34.894347] ? drm_ioctl_permit+0x210/0x210 [ 34.898649] ? __might_fault+0x192/0x1d0 [ 34.902699] drm_ioctl+0x5a0/0x9e0 [ 34.906222] ? drm_mode_create_dumb+0x300/0x300 [ 34.910874] ? drm_getstats+0x20/0x20 [ 34.914662] ? signal_setup_done+0xdd/0x460 [ 34.918962] ? get_signal+0x1f70/0x1f70 [ 34.922917] ? futex_exit_release+0x220/0x220 [ 34.927397] ? drm_getstats+0x20/0x20 [ 34.931186] do_vfs_ioctl+0xcdb/0x12e0 [ 34.935057] ? lock_downgrade+0x720/0x720 [ 34.939185] ? check_preemption_disabled+0x41/0x280 [ 34.944183] ? ioctl_preallocate+0x200/0x200 [ 34.948575] ? __fget+0x356/0x510 [ 34.952007] ? do_dup2+0x450/0x450 [ 34.955532] ? __se_sys_futex+0x298/0x3b0 [ 34.959661] ksys_ioctl+0x9b/0xc0 [ 34.963093] __x64_sys_ioctl+0x6f/0xb0 [ 34.966963] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 34.971527] do_syscall_64+0xf9/0x620 [ 34.975311] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 34.980478] RIP: 0033:0x7f479cad7c29 [ 34.984175] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 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 b8 ff ff ff f7 d8 64 89 01 48 [ 35.003053] RSP: 002b:00007f479ca841f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 35.010740] RAX: ffffffffffffffda RBX: 00007f479cb5c4c8 RCX: 00007f479cad7c29 [ 35.017988] RDX: 0000000020000000 RSI: 00000000c02064b2 RDI: 0000000000000003 [ 35.025239] RBP: 00007f479cb5c4c0 R08: 0000000000000000 R09: 0000000000000000 [ 35.032488] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f479cb5c4cc [ 35.039735] R13: 00007fffc1a2d3df R14: 00007f479ca84300 R15: 0000000000022000 [ 35.046987] [ 35.048593] Allocated by task 8861: [ 35.052206] kmem_cache_alloc_trace+0x12f/0x380 [ 35.056858] __vgem_gem_create+0x44/0xf0 [ 35.060986] vgem_gem_dumb_create+0xcf/0x240 [ 35.065373] drm_mode_create_dumb+0x27c/0x300 [ 35.069854] drm_ioctl_kernel+0x208/0x2a0 [ 35.073985] drm_ioctl+0x5a0/0x9e0 [ 35.077502] do_vfs_ioctl+0xcdb/0x12e0 [ 35.081370] ksys_ioctl+0x9b/0xc0 [ 35.084800] __x64_sys_ioctl+0x6f/0xb0 [ 35.088663] do_syscall_64+0xf9/0x620 [ 35.092444] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.097609] [ 35.099212] Freed by task 8861: [ 35.102471] kfree+0xcc/0x210 [ 35.105553] drm_gem_object_free+0x91/0x1c0 [ 35.109865] drm_gem_object_put_unlocked+0xd1/0x180 [ 35.114861] vgem_gem_dumb_create+0x10c/0x240 [ 35.119336] drm_mode_create_dumb+0x27c/0x300 [ 35.123815] drm_ioctl_kernel+0x208/0x2a0 [ 35.127941] drm_ioctl+0x5a0/0x9e0 [ 35.131460] do_vfs_ioctl+0xcdb/0x12e0 [ 35.135326] ksys_ioctl+0x9b/0xc0 [ 35.138756] __x64_sys_ioctl+0x6f/0xb0 [ 35.142624] do_syscall_64+0xf9/0x620 [ 35.146405] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.151567] [ 35.153174] The buggy address belongs to the object at ffff8880aaa24280 [ 35.153174] which belongs to the cache kmalloc-512 of size 512 [ 35.165809] The buggy address is located 256 bytes inside of [ 35.165809] 512-byte region [ffff8880aaa24280, ffff8880aaa24480) [ 35.177656] The buggy address belongs to the page: [ 35.182563] page:ffffea0002aa8900 count:1 mapcount:0 mapping:ffff88813bff0940 index:0xffff8880aaa24780 [ 35.191992] flags: 0xfff00000000100(slab) [ 35.196134] raw: 00fff00000000100 ffffea0002c57b48 ffffea0002adb008 ffff88813bff0940 [ 35.203999] raw: ffff8880aaa24780 ffff8880aaa24000 0000000100000004 0000000000000000 [ 35.211857] page dumped because: kasan: bad access detected [ 35.217553] [ 35.219156] Memory state around the buggy address: [ 35.224062] ffff8880aaa24280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 35.231397] ffff8880aaa24300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 35.238734] >ffff8880aaa24380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 35.246068] ^ [ 35.249414] ffff8880aaa24400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 35.256767] ffff8880aaa24480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 35.264107] ================================================================== [ 35.271465] Disabling lock debugging due to kernel taint [ 35.279380] Kernel panic - not syncing: panic_on_warn set ... [ 35.279380] [ 35.279395] CPU: 0 PID: 8861 Comm: syz-executor192 Tainted: G B 4.19.211-syzkaller #0 [ 35.279401] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.279405] Call Trace: [ 35.279424] dump_stack+0x1fc/0x2ef [ 35.279448] panic+0x26a/0x50e [ 35.314822] ? __warn_printk+0xf3/0xf3 [ 35.318707] ? preempt_schedule_common+0x45/0xc0 [ 35.323475] ? ___preempt_schedule+0x16/0x18 [ 35.327862] ? trace_hardirqs_on+0x55/0x210 [ 35.332162] kasan_end_report+0x43/0x49 [ 35.336117] kasan_report_error.cold+0xa7/0x1b9 [ 35.340768] ? vgem_gem_dumb_create+0x22c/0x240 [ 35.345432] __asan_report_load8_noabort+0x88/0x90 [ 35.350344] ? drm_gem_object_put_unlocked+0xa0/0x180 [ 35.355513] ? vgem_gem_dumb_create+0x22c/0x240 [ 35.360167] vgem_gem_dumb_create+0x22c/0x240 [ 35.364642] drm_mode_create_dumb+0x27c/0x300 [ 35.369122] drm_ioctl_kernel+0x208/0x2a0 [ 35.373258] ? drm_mode_create_dumb+0x300/0x300 [ 35.377904] ? drm_ioctl_permit+0x210/0x210 [ 35.382214] ? __might_fault+0x192/0x1d0 [ 35.386270] drm_ioctl+0x5a0/0x9e0 [ 35.389801] ? drm_mode_create_dumb+0x300/0x300 [ 35.394453] ? drm_getstats+0x20/0x20 [ 35.398242] ? signal_setup_done+0xdd/0x460 [ 35.402548] ? get_signal+0x1f70/0x1f70 [ 35.406508] ? futex_exit_release+0x220/0x220 [ 35.410988] ? drm_getstats+0x20/0x20 [ 35.414773] do_vfs_ioctl+0xcdb/0x12e0 [ 35.418670] ? lock_downgrade+0x720/0x720 [ 35.422825] ? check_preemption_disabled+0x41/0x280 [ 35.427826] ? ioctl_preallocate+0x200/0x200 [ 35.432216] ? __fget+0x356/0x510 [ 35.435654] ? do_dup2+0x450/0x450 [ 35.439181] ? __se_sys_futex+0x298/0x3b0 [ 35.443324] ksys_ioctl+0x9b/0xc0 [ 35.446759] __x64_sys_ioctl+0x6f/0xb0 [ 35.450628] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 35.455187] do_syscall_64+0xf9/0x620 [ 35.458973] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.464145] RIP: 0033:0x7f479cad7c29 [ 35.467834] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 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 b8 ff ff ff f7 d8 64 89 01 48 [ 35.486712] RSP: 002b:00007f479ca841f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 35.494400] RAX: ffffffffffffffda RBX: 00007f479cb5c4c8 RCX: 00007f479cad7c29 [ 35.501781] RDX: 0000000020000000 RSI: 00000000c02064b2 RDI: 0000000000000003 [ 35.509034] RBP: 00007f479cb5c4c0 R08: 0000000000000000 R09: 0000000000000000 [ 35.516282] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f479cb5c4cc [ 35.523528] R13: 00007fffc1a2d3df R14: 00007f479ca84300 R15: 0000000000022000 [ 35.530952] Kernel Offset: disabled [ 35.534560] Rebooting in 86400 seconds..