[ 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... 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 '10.128.0.230' (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 syzkaller login: [ 34.372304] ================================================================== [ 34.379862] BUG: KASAN: use-after-free in vgem_gem_dumb_create+0x22c/0x240 [ 34.386881] Read of size 8 at addr ffff8880a2d21b00 by task syz-executor041/8440 [ 34.394409] [ 34.396040] CPU: 0 PID: 8440 Comm: syz-executor041 Not tainted 4.19.188-syzkaller #0 [ 34.403916] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 34.413267] Call Trace: [ 34.415860] dump_stack+0x1fc/0x2ef executing program executing program executing program executing program [ 34.419502] print_address_description.cold+0x54/0x219 [ 34.424779] kasan_report_error.cold+0x8a/0x1b9 [ 34.429466] ? vgem_gem_dumb_create+0x22c/0x240 [ 34.434138] __asan_report_load8_noabort+0x88/0x90 [ 34.439067] ? drm_gem_object_put_unlocked+0xc0/0x180 [ 34.444246] ? vgem_gem_dumb_create+0x22c/0x240 [ 34.448912] vgem_gem_dumb_create+0x22c/0x240 [ 34.453416] drm_mode_create_dumb+0x27c/0x300 [ 34.457933] drm_ioctl_kernel+0x208/0x2a0 [ 34.462067] ? drm_mode_create_dumb+0x300/0x300 [ 34.466725] ? drm_ioctl_permit+0x210/0x210 [ 34.471030] ? __might_fault+0x192/0x1d0 [ 34.475075] drm_ioctl+0x507/0x9c0 [ 34.478604] ? drm_mode_create_dumb+0x300/0x300 [ 34.483275] ? drm_getstats+0x20/0x20 [ 34.487118] ? cmp_ex_sort+0xc0/0xc0 [ 34.490819] ? __do_page_fault+0x180/0xd60 [ 34.495036] ? retint_kernel+0x2d/0x2d [ 34.498910] ? futex_exit_release+0x220/0x220 [ 34.503404] ? drm_getstats+0x20/0x20 [ 34.507201] do_vfs_ioctl+0xcdb/0x12e0 [ 34.511079] ? lock_downgrade+0x720/0x720 [ 34.515222] ? check_preemption_disabled+0x41/0x280 [ 34.520241] ? ioctl_preallocate+0x200/0x200 [ 34.524662] ? __fget+0x356/0x510 [ 34.528102] ? do_dup2+0x450/0x450 [ 34.531632] ? __se_sys_futex+0x298/0x3b0 [ 34.535769] ksys_ioctl+0x9b/0xc0 [ 34.539209] __x64_sys_ioctl+0x6f/0xb0 [ 34.543084] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 34.547650] do_syscall_64+0xf9/0x620 [ 34.551443] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 34.556616] RIP: 0033:0x449fc9 [ 34.559798] 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 b8 ff ff ff f7 d8 64 89 01 48 [ 34.578683] RSP: 002b:00007f06b03c3308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 34.586374] RAX: ffffffffffffffda RBX: 00000000004ca448 RCX: 0000000000449fc9 [ 34.593627] RDX: 00000000200000c0 RSI: 00000000c02064b2 RDI: 0000000000000006 [ 34.601056] RBP: 00000000004ca440 R08: 0000000000000000 R09: 0000000000000000 [ 34.608309] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca44c [ 34.615559] R13: 000000000049a074 R14: 6972642f7665642f R15: 0000000000022000 [ 34.622821] [ 34.624429] Allocated by task 8440: [ 34.628039] kmem_cache_alloc_trace+0x12f/0x380 [ 34.632689] __vgem_gem_create+0x44/0xf0 [ 34.636731] vgem_gem_dumb_create+0xcf/0x240 [ 34.641123] drm_mode_create_dumb+0x27c/0x300 [ 34.645600] drm_ioctl_kernel+0x208/0x2a0 [ 34.649727] drm_ioctl+0x507/0x9c0 [ 34.653248] do_vfs_ioctl+0xcdb/0x12e0 [ 34.657115] ksys_ioctl+0x9b/0xc0 [ 34.660550] __x64_sys_ioctl+0x6f/0xb0 [ 34.664423] do_syscall_64+0xf9/0x620 [ 34.668206] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 34.673384] [ 34.674999] Freed by task 8440: [ 34.678264] kfree+0xcc/0x210 [ 34.681357] drm_gem_object_free+0x91/0x1c0 [ 34.685678] drm_gem_object_put_unlocked+0xd1/0x180 [ 34.690685] vgem_gem_dumb_create+0x10c/0x240 [ 34.695169] drm_mode_create_dumb+0x27c/0x300 [ 34.699648] drm_ioctl_kernel+0x208/0x2a0 [ 34.703778] drm_ioctl+0x507/0x9c0 [ 34.707311] do_vfs_ioctl+0xcdb/0x12e0 [ 34.711177] ksys_ioctl+0x9b/0xc0 [ 34.714612] __x64_sys_ioctl+0x6f/0xb0 [ 34.718502] do_syscall_64+0xf9/0x620 [ 34.722285] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 34.727451] [ 34.729060] The buggy address belongs to the object at ffff8880a2d21a00 [ 34.729060] which belongs to the cache kmalloc-512 of size 512 [ 34.741699] The buggy address is located 256 bytes inside of [ 34.741699] 512-byte region [ffff8880a2d21a00, ffff8880a2d21c00) [ 34.753557] The buggy address belongs to the page: [ 34.758471] page:ffffea00028b4840 count:1 mapcount:0 mapping:ffff88813bff0940 index:0x0 [ 34.766591] flags: 0xfff00000000100(slab) [ 34.770729] raw: 00fff00000000100 ffffea00025d8008 ffffea0002843648 ffff88813bff0940 [ 34.778592] raw: 0000000000000000 ffff8880a2d21000 0000000100000006 0000000000000000 [ 34.786450] page dumped because: kasan: bad access detected [ 34.792136] [ 34.793740] Memory state around the buggy address: [ 34.798648] ffff8880a2d21a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.805988] ffff8880a2d21a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.813330] >ffff8880a2d21b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.820665] ^ executing program [ 34.824009] ffff8880a2d21b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 34.831350] ffff8880a2d21c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 34.838686] ================================================================== [ 34.846023] Disabling lock debugging due to kernel taint [ 34.857137] Kernel panic - not syncing: panic_on_warn set ... [ 34.857137] [ 34.864543] CPU: 1 PID: 8440 Comm: syz-executor041 Tainted: G B 4.19.188-syzkaller #0 executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.873807] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 34.883162] Call Trace: [ 34.885752] dump_stack+0x1fc/0x2ef [ 34.889381] panic+0x26a/0x50e [ 34.892574] ? __warn_printk+0xf3/0xf3 [ 34.896465] ? preempt_schedule_common+0x45/0xc0 [ 34.901227] ? ___preempt_schedule+0x16/0x18 [ 34.905638] ? trace_hardirqs_on+0x55/0x210 [ 34.909965] kasan_end_report+0x43/0x49 [ 34.913942] kasan_report_error.cold+0xa7/0x1b9 [ 34.918612] ? vgem_gem_dumb_create+0x22c/0x240 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.923283] __asan_report_load8_noabort+0x88/0x90 [ 34.928217] ? drm_gem_object_put_unlocked+0xc0/0x180 [ 34.933409] ? vgem_gem_dumb_create+0x22c/0x240 [ 34.938084] vgem_gem_dumb_create+0x22c/0x240 [ 34.942585] drm_mode_create_dumb+0x27c/0x300 [ 34.947087] drm_ioctl_kernel+0x208/0x2a0 [ 34.951236] ? drm_mode_create_dumb+0x300/0x300 [ 34.955907] ? drm_ioctl_permit+0x210/0x210 [ 34.960232] ? __might_fault+0x192/0x1d0 [ 34.964295] drm_ioctl+0x507/0x9c0 [ 34.967839] ? drm_mode_create_dumb+0x300/0x300 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 34.972510] ? drm_getstats+0x20/0x20 [ 34.976316] ? cmp_ex_sort+0xc0/0xc0 [ 34.980034] ? __do_page_fault+0x180/0xd60 [ 34.984274] ? retint_kernel+0x2d/0x2d [ 34.988166] ? futex_exit_release+0x220/0x220 [ 34.992667] ? drm_getstats+0x20/0x20 [ 34.996470] do_vfs_ioctl+0xcdb/0x12e0 [ 35.000363] ? lock_downgrade+0x720/0x720 [ 35.004515] ? check_preemption_disabled+0x41/0x280 [ 35.009536] ? ioctl_preallocate+0x200/0x200 [ 35.013945] ? __fget+0x356/0x510 [ 35.017398] ? do_dup2+0x450/0x450 [ 35.020942] ? __se_sys_futex+0x298/0x3b0 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 35.025098] ksys_ioctl+0x9b/0xc0 [ 35.028564] __x64_sys_ioctl+0x6f/0xb0 [ 35.032455] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 35.037036] do_syscall_64+0xf9/0x620 [ 35.040840] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.046031] RIP: 0033:0x449fc9 [ 35.049227] 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 b8 ff ff ff f7 d8 64 89 01 48 executing program executing program executing program executing program executing program executing program executing program executing program [ 35.068123] RSP: 002b:00007f06b03c3308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 35.075829] RAX: ffffffffffffffda RBX: 00000000004ca448 RCX: 0000000000449fc9 [ 35.083096] RDX: 00000000200000c0 RSI: 00000000c02064b2 RDI: 0000000000000006 [ 35.090365] RBP: 00000000004ca440 R08: 0000000000000000 R09: 0000000000000000 [ 35.097630] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca44c [ 35.104902] R13: 000000000049a074 R14: 6972642f7665642f R15: 0000000000022000 [ 35.112815] Kernel Offset: disabled [ 35.116495] Rebooting in 86400 seconds..