[ 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 '10.128.0.211' (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 syzkaller login: [ 33.256340] ================================================================== [ 33.263984] BUG: KASAN: use-after-free in vgem_gem_dumb_create+0x200/0x210 [ 33.271002] Read of size 8 at addr ffff8880a376f400 by task syz-executor557/8188 [ 33.278539] [ 33.280168] CPU: 0 PID: 8188 Comm: syz-executor557 Not tainted 4.14.217-syzkaller #0 [ 33.288047] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.297506] Call Trace: [ 33.300116] dump_stack+0x1b2/0x281 executing program executing program executing program executing program executing program executing program executing program executing program [ 33.303754] print_address_description.cold+0x54/0x1d3 [ 33.309044] kasan_report_error.cold+0x8a/0x191 [ 33.313722] ? vgem_gem_dumb_create+0x200/0x210 [ 33.318397] __asan_report_load8_noabort+0x68/0x70 [ 33.323337] ? vgem_gem_dumb_create+0x200/0x210 [ 33.328011] vgem_gem_dumb_create+0x200/0x210 [ 33.332521] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 33.337640] ? __drm_printfn_debug+0x70/0x70 [ 33.342072] drm_ioctl_kernel+0x14c/0x200 [ 33.347536] drm_ioctl+0x419/0x870 [ 33.351087] ? __drm_printfn_debug+0x70/0x70 executing program executing program executing program executing program executing program executing program executing program executing program [ 33.355498] ? drm_getstats+0x20/0x20 [ 33.359328] ? futex_exit_release+0x220/0x220 [ 33.363835] ? __fget+0x225/0x360 [ 33.367294] ? __fdget+0x167/0x1f0 [ 33.370838] ? drm_getstats+0x20/0x20 [ 33.374645] do_vfs_ioctl+0x75a/0xff0 [ 33.378466] ? ioctl_preallocate+0x1a0/0x1a0 [ 33.382888] ? lock_downgrade+0x740/0x740 [ 33.387042] ? __fget+0x225/0x360 [ 33.390498] ? do_vfs_ioctl+0xff0/0xff0 [ 33.394474] ? security_file_ioctl+0x83/0xb0 [ 33.398884] SyS_ioctl+0x7f/0xb0 [ 33.402249] ? do_vfs_ioctl+0xff0/0xff0 executing program executing program executing program executing program executing program executing program executing program executing program [ 33.406225] do_syscall_64+0x1d5/0x640 [ 33.410172] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 33.415358] RIP: 0033:0x44a999 [ 33.418543] RSP: 002b:00007f9010a96ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 33.426280] RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 000000000044a999 [ 33.433571] RDX: 00000000200000c0 RSI: 00000000c02064b2 RDI: 0000000000000004 [ 33.440848] RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000 [ 33.448122] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c executing program executing program executing program executing program executing program executing program executing program [ 33.455408] R13: 00007fff3eacbc3f R14: 00007f9010a979c0 R15: 0000000000000000 [ 33.462696] [ 33.464330] Allocated by task 8188: [ 33.467956] kasan_kmalloc+0xeb/0x160 [ 33.471790] kmem_cache_alloc_trace+0x131/0x3d0 [ 33.476464] __vgem_gem_create+0x44/0xe0 [ 33.480532] vgem_gem_dumb_create+0xc5/0x210 [ 33.484954] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 33.489974] drm_ioctl_kernel+0x14c/0x200 [ 33.494127] drm_ioctl+0x419/0x870 [ 33.497668] do_vfs_ioctl+0x75a/0xff0 [ 33.501468] SyS_ioctl+0x7f/0xb0 executing program executing program executing program executing program executing program executing program executing program executing program [ 33.504827] do_syscall_64+0x1d5/0x640 [ 33.508717] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 33.513902] [ 33.515522] Freed by task 8188: [ 33.518802] kasan_slab_free+0xc3/0x1a0 [ 33.522779] kfree+0xc9/0x250 [ 33.525884] drm_gem_object_free+0x8f/0x150 [ 33.530204] drm_gem_object_put_unlocked+0xc3/0x160 [ 33.535230] vgem_gem_dumb_create+0xf2/0x210 [ 33.539651] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 33.544666] drm_ioctl_kernel+0x14c/0x200 [ 33.548821] drm_ioctl+0x419/0x870 [ 33.552369] do_vfs_ioctl+0x75a/0xff0 executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 33.556200] SyS_ioctl+0x7f/0xb0 [ 33.559603] do_syscall_64+0x1d5/0x640 [ 33.563587] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 33.569035] [ 33.570664] The buggy address belongs to the object at ffff8880a376f300 [ 33.570664] which belongs to the cache kmalloc-512 of size 512 [ 33.583350] The buggy address is located 256 bytes inside of [ 33.583350] 512-byte region [ffff8880a376f300, ffff8880a376f500) [ 33.595408] The buggy address belongs to the page: executing program executing program executing program executing program executing program executing program executing program executing program [ 33.600346] page:ffffea00028ddbc0 count:1 mapcount:0 mapping:ffff8880a376f080 index:0x0 [ 33.608495] flags: 0xfff00000000100(slab) [ 33.612653] raw: 00fff00000000100 ffff8880a376f080 0000000000000000 0000000100000006 [ 33.620538] raw: ffffea00027e70e0 ffffea00028dd860 ffff88813fe80940 0000000000000000 [ 33.628421] page dumped because: kasan: bad access detected [ 33.634137] [ 33.635800] Memory state around the buggy address: [ 33.640728] ffff8880a376f300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.648093] ffff8880a376f380: 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 executing program executing program executing program executing program [ 33.655456] >ffff8880a376f400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.662818] ^ [ 33.666882] ffff8880a376f480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 33.674245] ffff8880a376f500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 33.681606] ================================================================== [ 33.688973] Disabling lock debugging due to kernel taint executing program executing program executing program executing program executing program executing program executing program [ 33.711290] Kernel panic - not syncing: panic_on_warn set ... [ 33.711290] [ 33.718818] CPU: 0 PID: 8188 Comm: syz-executor557 Tainted: G B 4.14.217-syzkaller #0 [ 33.727917] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.738575] Call Trace: [ 33.741163] dump_stack+0x1b2/0x281 [ 33.744797] panic+0x1f9/0x42d [ 33.747993] ? add_taint.cold+0x16/0x16 [ 33.751974] ? ___preempt_schedule+0x16/0x18 [ 33.756391] kasan_end_report+0x43/0x49 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 33.760372] kasan_report_error.cold+0xa7/0x191 [ 33.765042] ? vgem_gem_dumb_create+0x200/0x210 [ 33.769712] __asan_report_load8_noabort+0x68/0x70 [ 33.774652] ? vgem_gem_dumb_create+0x200/0x210 [ 33.779325] vgem_gem_dumb_create+0x200/0x210 [ 33.783825] drm_mode_create_dumb_ioctl+0x221/0x2b0 [ 33.788849] ? __drm_printfn_debug+0x70/0x70 [ 33.793263] drm_ioctl_kernel+0x14c/0x200 [ 33.797412] drm_ioctl+0x419/0x870 [ 33.800955] ? __drm_printfn_debug+0x70/0x70 [ 33.805391] ? drm_getstats+0x20/0x20 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 33.809195] ? futex_exit_release+0x220/0x220 [ 33.813694] ? __fget+0x225/0x360 [ 33.817183] ? __fdget+0x167/0x1f0 [ 33.820720] ? drm_getstats+0x20/0x20 [ 33.824520] do_vfs_ioctl+0x75a/0xff0 [ 33.828361] ? ioctl_preallocate+0x1a0/0x1a0 [ 33.832769] ? lock_downgrade+0x740/0x740 [ 33.837640] ? __fget+0x225/0x360 [ 33.841106] ? do_vfs_ioctl+0xff0/0xff0 [ 33.845080] ? security_file_ioctl+0x83/0xb0 [ 33.849494] SyS_ioctl+0x7f/0xb0 [ 33.852861] ? do_vfs_ioctl+0xff0/0xff0 [ 33.856837] do_syscall_64+0x1d5/0x640 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 33.860741] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 33.865930] RIP: 0033:0x44a999 [ 33.869113] RSP: 002b:00007f9010a96ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 33.876822] RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 000000000044a999 [ 33.884288] RDX: 00000000200000c0 RSI: 00000000c02064b2 RDI: 0000000000000004 [ 33.891569] RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000 [ 33.898960] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c [ 33.906230] R13: 00007fff3eacbc3f R14: 00007f9010a979c0 R15: 0000000000000000 [ 33.914143] Kernel Offset: disabled [ 33.917863] Rebooting in 86400 seconds..