[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 55.321926][ T23] audit: type=1800 audit(1573486599.147:25): pid=8673 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 55.341833][ T23] audit: type=1800 audit(1573486599.147:26): pid=8673 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 55.387538][ T23] audit: type=1800 audit(1573486599.157:27): pid=8673 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.74' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 66.240741][ T8825] ================================================================== [ 66.248948][ T8825] BUG: KASAN: use-after-free in __list_add_valid+0x9a/0xa0 [ 66.256125][ T8825] Read of size 8 at addr ffff88809fccee78 by task syz-executor075/8825 [ 66.264944][ T8825] [ 66.267259][ T8825] CPU: 0 PID: 8825 Comm: syz-executor075 Not tainted 5.4.0-rc6-next-20191111 #0 [ 66.276443][ T8825] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.286567][ T8825] Call Trace: [ 66.289842][ T8825] dump_stack+0x197/0x210 [ 66.294211][ T8825] ? __list_add_valid+0x9a/0xa0 [ 66.299041][ T8825] print_address_description.constprop.0.cold+0xd4/0x30b [ 66.306043][ T8825] ? __list_add_valid+0x9a/0xa0 [ 66.310961][ T8825] ? __list_add_valid+0x9a/0xa0 [ 66.315813][ T8825] __kasan_report.cold+0x1b/0x41 [ 66.320733][ T8825] ? __list_add_valid+0x9a/0xa0 [ 66.325562][ T8825] kasan_report+0x12/0x20 [ 66.329870][ T8825] __asan_report_load8_noabort+0x14/0x20 [ 66.335481][ T8825] __list_add_valid+0x9a/0xa0 [ 66.340149][ T8825] snd_timer_open+0x245/0x1150 [ 66.344909][ T8825] ? kmem_cache_alloc_trace+0x397/0x790 [ 66.350447][ T8825] ? snd_timer_close_locked+0xbd0/0xbd0 [ 66.355975][ T8825] ? kstrdup+0x5a/0x70 [ 66.360030][ T8825] __snd_timer_user_ioctl.isra.0+0x7ed/0x2070 [ 66.366105][ T8825] ? snd_timer_user_open+0x190/0x190 [ 66.371374][ T8825] ? lock_acquire+0x190/0x410 [ 66.376030][ T8825] ? snd_timer_user_ioctl+0x51/0xa7 [ 66.381210][ T8825] ? __mutex_lock+0x458/0x13c0 [ 66.385953][ T8825] ? snd_timer_user_ioctl+0x51/0xa7 [ 66.391130][ T8825] ? tomoyo_path_number_perm+0x454/0x520 [ 66.396744][ T8825] ? mutex_trylock+0x2f0/0x2f0 [ 66.401498][ T8825] ? tomoyo_path_number_perm+0x25e/0x520 [ 66.407195][ T8825] ? tomoyo_execute_permission+0x4a0/0x4a0 [ 66.413005][ T8825] snd_timer_user_ioctl+0x7a/0xa7 [ 66.418010][ T8825] ? snd_timer_user_ioctl_compat+0x680/0x680 [ 66.423990][ T8825] do_vfs_ioctl+0x977/0x14e0 [ 66.428561][ T8825] ? compat_ioctl_preallocate+0x220/0x220 [ 66.434347][ T8825] ? __kasan_check_write+0x14/0x20 [ 66.439436][ T8825] ? up_read+0x1cd/0x810 [ 66.443659][ T8825] ? tomoyo_file_ioctl+0x23/0x30 [ 66.448617][ T8825] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 66.454863][ T8825] ? security_file_ioctl+0x8d/0xc0 [ 66.459968][ T8825] ksys_ioctl+0xab/0xd0 [ 66.464111][ T8825] __x64_sys_ioctl+0x73/0xb0 [ 66.468689][ T8825] do_syscall_64+0xfa/0x760 [ 66.473176][ T8825] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.479051][ T8825] RIP: 0033:0x444f39 [ 66.482925][ T8825] Code: e8 fc ab 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 0f 83 bb cd fb ff c3 66 2e 0f 1f 84 00 00 00 00 [ 66.502516][ T8825] RSP: 002b:00007ffd1d1e3c98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 66.510924][ T8825] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000444f39 [ 66.518881][ T8825] RDX: 0000000020029fcc RSI: 0000000040345410 RDI: 0000000000000003 [ 66.526835][ T8825] RBP: 00000000000102a7 R08: 0000000000000004 R09: 00000000004002e0 [ 66.534790][ T8825] R10: 000000000000000f R11: 0000000000000246 R12: 0000000000402180 [ 66.542749][ T8825] R13: 0000000000402210 R14: 0000000000000000 R15: 0000000000000000 [ 66.550787][ T8825] [ 66.553098][ T8825] Allocated by task 8824: [ 66.557413][ T8825] save_stack+0x23/0x90 [ 66.561562][ T8825] __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 66.567169][ T8825] kasan_kmalloc+0x9/0x10 [ 66.571498][ T8825] kmem_cache_alloc_trace+0x158/0x790 [ 66.576849][ T8825] snd_timer_instance_new+0x4a/0x300 [ 66.582114][ T8825] __snd_timer_user_ioctl.isra.0+0x665/0x2070 [ 66.588157][ T8825] snd_timer_user_ioctl+0x7a/0xa7 [ 66.593505][ T8825] do_vfs_ioctl+0x977/0x14e0 [ 66.598071][ T8825] ksys_ioctl+0xab/0xd0 [ 66.602202][ T8825] __x64_sys_ioctl+0x73/0xb0 [ 66.606771][ T8825] do_syscall_64+0xfa/0x760 [ 66.611249][ T8825] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.617117][ T8825] [ 66.619436][ T8825] Freed by task 8824: [ 66.623393][ T8825] save_stack+0x23/0x90 [ 66.627524][ T8825] __kasan_slab_free+0x102/0x150 [ 66.632434][ T8825] kasan_slab_free+0xe/0x10 [ 66.636920][ T8825] kfree+0x10a/0x2c0 [ 66.640802][ T8825] snd_timer_instance_free+0x7c/0xa0 [ 66.646063][ T8825] __snd_timer_user_ioctl.isra.0+0x160d/0x2070 [ 66.652188][ T8825] snd_timer_user_ioctl+0x7a/0xa7 [ 66.657189][ T8825] do_vfs_ioctl+0x977/0x14e0 [ 66.661784][ T8825] ksys_ioctl+0xab/0xd0 [ 66.665911][ T8825] __x64_sys_ioctl+0x73/0xb0 [ 66.670477][ T8825] do_syscall_64+0xfa/0x760 [ 66.674957][ T8825] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.680816][ T8825] [ 66.683127][ T8825] The buggy address belongs to the object at ffff88809fccee00 [ 66.683127][ T8825] which belongs to the cache kmalloc-256 of size 256 [ 66.697154][ T8825] The buggy address is located 120 bytes inside of [ 66.697154][ T8825] 256-byte region [ffff88809fccee00, ffff88809fccef00) [ 66.710396][ T8825] The buggy address belongs to the page: [ 66.716010][ T8825] page:ffffea00027f3380 refcount:1 mapcount:0 mapping:ffff8880aa4008c0 index:0x0 [ 66.725101][ T8825] flags: 0x1fffc0000000200(slab) [ 66.730018][ T8825] raw: 01fffc0000000200 ffffea00027f2e08 ffff8880aa401648 ffff8880aa4008c0 [ 66.738578][ T8825] raw: 0000000000000000 ffff88809fcce000 0000000100000008 0000000000000000 [ 66.747132][ T8825] page dumped because: kasan: bad access detected [ 66.753513][ T8825] [ 66.755816][ T8825] Memory state around the buggy address: [ 66.761426][ T8825] ffff88809fcced00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 66.769463][ T8825] ffff88809fcced80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 66.777508][ T8825] >ffff88809fccee00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.785571][ T8825] ^ [ 66.793532][ T8825] ffff88809fccee80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 66.801568][ T8825] ffff88809fccef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 66.809601][ T8825] ================================================================== [ 66.817643][ T8825] Disabling lock debugging due to kernel taint [ 66.824330][ T8825] Kernel panic - not syncing: panic_on_warn set ... [ 66.830918][ T8825] CPU: 0 PID: 8825 Comm: syz-executor075 Tainted: G B 5.4.0-rc6-next-20191111 #0 [ 66.841298][ T8825] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.851329][ T8825] Call Trace: [ 66.854597][ T8825] dump_stack+0x197/0x210 [ 66.858901][ T8825] panic+0x2e3/0x75c [ 66.862771][ T8825] ? add_taint.cold+0x16/0x16 [ 66.867430][ T8825] ? __list_add_valid+0x9a/0xa0 [ 66.872261][ T8825] ? preempt_schedule+0x4b/0x60 [ 66.877085][ T8825] ? ___preempt_schedule+0x16/0x18 [ 66.882168][ T8825] ? trace_hardirqs_on+0x5e/0x240 [ 66.887170][ T8825] ? __list_add_valid+0x9a/0xa0 [ 66.891997][ T8825] end_report+0x47/0x4f [ 66.896126][ T8825] ? __list_add_valid+0x9a/0xa0 [ 66.900957][ T8825] __kasan_report.cold+0xe/0x41 [ 66.905781][ T8825] ? __list_add_valid+0x9a/0xa0 [ 66.910616][ T8825] kasan_report+0x12/0x20 [ 66.914935][ T8825] __asan_report_load8_noabort+0x14/0x20 [ 66.920550][ T8825] __list_add_valid+0x9a/0xa0 [ 66.925208][ T8825] snd_timer_open+0x245/0x1150 [ 66.929951][ T8825] ? kmem_cache_alloc_trace+0x397/0x790 [ 66.935489][ T8825] ? snd_timer_close_locked+0xbd0/0xbd0 [ 66.941027][ T8825] ? kstrdup+0x5a/0x70 [ 66.945077][ T8825] __snd_timer_user_ioctl.isra.0+0x7ed/0x2070 [ 66.952336][ T8825] ? snd_timer_user_open+0x190/0x190 [ 66.957599][ T8825] ? lock_acquire+0x190/0x410 [ 66.962254][ T8825] ? snd_timer_user_ioctl+0x51/0xa7 [ 66.967438][ T8825] ? __mutex_lock+0x458/0x13c0 [ 66.972198][ T8825] ? snd_timer_user_ioctl+0x51/0xa7 [ 66.977386][ T8825] ? tomoyo_path_number_perm+0x454/0x520 [ 66.982996][ T8825] ? mutex_trylock+0x2f0/0x2f0 [ 66.987734][ T8825] ? tomoyo_path_number_perm+0x25e/0x520 [ 66.993342][ T8825] ? tomoyo_execute_permission+0x4a0/0x4a0 [ 66.999132][ T8825] snd_timer_user_ioctl+0x7a/0xa7 [ 67.004142][ T8825] ? snd_timer_user_ioctl_compat+0x680/0x680 [ 67.010103][ T8825] do_vfs_ioctl+0x977/0x14e0 [ 67.014669][ T8825] ? compat_ioctl_preallocate+0x220/0x220 [ 67.020367][ T8825] ? __kasan_check_write+0x14/0x20 [ 67.025464][ T8825] ? up_read+0x1cd/0x810 [ 67.029697][ T8825] ? tomoyo_file_ioctl+0x23/0x30 [ 67.034620][ T8825] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 67.040847][ T8825] ? security_file_ioctl+0x8d/0xc0 [ 67.045936][ T8825] ksys_ioctl+0xab/0xd0 [ 67.050067][ T8825] __x64_sys_ioctl+0x73/0xb0 [ 67.054633][ T8825] do_syscall_64+0xfa/0x760 [ 67.059115][ T8825] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.064993][ T8825] RIP: 0033:0x444f39 [ 67.068867][ T8825] Code: e8 fc ab 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 0f 83 bb cd fb ff c3 66 2e 0f 1f 84 00 00 00 00 [ 67.088455][ T8825] RSP: 002b:00007ffd1d1e3c98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 67.096842][ T8825] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000444f39 [ 67.104805][ T8825] RDX: 0000000020029fcc RSI: 0000000040345410 RDI: 0000000000000003 [ 67.112751][ T8825] RBP: 00000000000102a7 R08: 0000000000000004 R09: 00000000004002e0 [ 67.120700][ T8825] R10: 000000000000000f R11: 0000000000000246 R12: 0000000000402180 [ 67.128646][ T8825] R13: 0000000000402210 R14: 0000000000000000 R15: 0000000000000000 [ 67.137945][ T8825] Kernel Offset: disabled [ 67.142266][ T8825] Rebooting in 86400 seconds..