[....] Starting enhanced syslogd: rsyslogd[ 14.866253] audit: type=1400 audit(1549089118.967:4): avc: denied { syslog } for pid=1923 comm="rsyslogd" capability=34 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=capability2 permissive=1 [?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.89' (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 syzkaller login: [ 35.608329] ================================================================== [ 35.615887] BUG: KASAN: use-after-free in disk_unblock_events+0x55/0x60 [ 35.622634] Read of size 8 at addr ffff8801d4244968 by task blkid/2426 [ 35.629288] [ 35.630919] CPU: 0 PID: 2426 Comm: blkid Not tainted 4.4.172+ #13 [ 35.637137] 0000000000000000 cac3e95efbea6b0f ffff8800b5d67730 ffffffff81aacde1 [ 35.645282] 0000000000000000 ffffea0007509000 ffff8801d4244968 0000000000000008 [ 35.653352] 0000000000000000 ffff8800b5d67768 ffffffff8148fedd 0000000000000000 [ 35.661409] Call Trace: [ 35.664003] [] dump_stack+0xc1/0x120 [ 35.669360] [] print_address_description+0x6f/0x21b [ 35.676036] [] kasan_report.cold+0x8c/0x2be [ 35.682000] [] ? disk_unblock_events+0x55/0x60 [ 35.688227] [] __asan_report_load8_noabort+0x14/0x20 [ 35.694986] [] disk_unblock_events+0x55/0x60 [ 35.701035] [] __blkdev_get+0x70c/0xdf0 [ 35.706657] [] ? __blkdev_put+0x840/0x840 [ 35.712454] [] ? trace_hardirqs_on+0x10/0x10 [ 35.718505] [] blkdev_get+0x2e8/0x920 [ 35.723951] [] ? bd_may_claim+0xd0/0xd0 [ 35.729565] [] ? bd_acquire+0x8a/0x370 [ 35.735105] [] ? _raw_spin_unlock+0x2d/0x50 [ 35.741085] [] blkdev_open+0x1aa/0x250 [ 35.746627] [] do_dentry_open+0x38f/0xbd0 [ 35.752744] [] ? __inode_permission2+0x9e/0x250 [ 35.759041] [] ? blkdev_get_by_dev+0x80/0x80 [ 35.765086] [] vfs_open+0x10b/0x210 [ 35.770355] [] ? may_open.isra.0+0xe7/0x210 [ 35.776318] [] path_openat+0x136f/0x4470 [ 35.782032] [] ? kasan_kmalloc.part.0+0xc6/0xf0 [ 35.788341] [] ? may_open.isra.0+0x210/0x210 [ 35.794395] [] ? trace_hardirqs_on+0x10/0x10 [ 35.800455] [] do_filp_open+0x1a1/0x270 [ 35.806076] [] ? user_path_mountpoint_at+0x50/0x50 [ 35.812649] [] ? __alloc_fd+0x1ea/0x490 [ 35.818266] [] ? _raw_spin_unlock+0x2d/0x50 [ 35.824231] [] do_sys_open+0x2f8/0x600 [ 35.829764] [] ? filp_open+0x70/0x70 [ 35.835124] [] ? retint_user+0x18/0x3c [ 35.840655] [] ? trace_hardirqs_on_caller+0x385/0x5a0 [ 35.847486] [] SyS_open+0x2d/0x40 [ 35.852587] [] entry_SYSCALL_64_fastpath+0x1e/0x9a [ 35.859152] [ 35.860772] Allocated by task 2382: [ 35.864385] [] save_stack_trace+0x26/0x50 [ 35.870319] [] kasan_kmalloc.part.0+0x62/0xf0 [ 35.876596] [] kasan_kmalloc+0xb7/0xd0 [ 35.882262] [] kmem_cache_alloc_trace+0x123/0x2d0 [ 35.888880] [] alloc_disk_node+0x50/0x3c0 [ 35.894815] [] alloc_disk+0x1b/0x20 [ 35.900219] [] loop_add+0x380/0x830 [ 35.905625] [] loop_probe+0x154/0x180 [ 35.911203] [] kobj_lookup+0x221/0x410 [ 35.916862] [] get_gendisk+0x3c/0x2e0 [ 35.922450] [] __blkdev_get+0x39c/0xdf0 [ 35.928201] [] blkdev_get+0x481/0x920 [ 35.933776] [] blkdev_open+0x1aa/0x250 [ 35.939439] [] do_dentry_open+0x38f/0xbd0 [ 35.945368] [] vfs_open+0x10b/0x210 [ 35.950796] [] path_openat+0x136f/0x4470 [ 35.956639] [] do_filp_open+0x1a1/0x270 [ 35.962419] [] do_sys_open+0x2f8/0x600 [ 35.968079] [] compat_SyS_open+0x2a/0x40 [ 35.973910] [] do_fast_syscall_32+0x32d/0xa90 [ 35.980195] [] sysenter_flags_fixed+0xd/0x1a [ 35.986410] [ 35.988030] Freed by task 2426: [ 35.991295] [] save_stack_trace+0x26/0x50 [ 35.997220] [] kasan_slab_free+0xb0/0x190 [ 36.003147] [] kfree+0xf4/0x310 [ 36.008209] [] disk_release+0x255/0x330 [ 36.014086] [] device_release+0x7d/0x220 [ 36.019929] [] kobject_put+0x14c/0x260 [ 36.025591] [] put_disk+0x23/0x30 [ 36.030826] [] __blkdev_get+0x66c/0xdf0 [ 36.036596] [] blkdev_get+0x2e8/0x920 [ 36.042174] [] blkdev_open+0x1aa/0x250 [ 36.047858] [] do_dentry_open+0x38f/0xbd0 [ 36.053791] [] vfs_open+0x10b/0x210 [ 36.059223] [] path_openat+0x136f/0x4470 [ 36.059232] [] do_filp_open+0x1a1/0x270 [ 36.059240] [] do_sys_open+0x2f8/0x600 [ 36.059250] [] SyS_open+0x2d/0x40 [ 36.059259] [] entry_SYSCALL_64_fastpath+0x1e/0x9a [ 36.059261] [ 36.059265] The buggy address belongs to the object at ffff8801d4244400 [ 36.059265] which belongs to the cache kmalloc-2048 of size 2048 [ 36.059269] The buggy address is located 1384 bytes inside of [ 36.059269] 2048-byte region [ffff8801d4244400, ffff8801d4244c00) [ 36.059271] The buggy address belongs to the page: [ 36.068890] INFO: trying to register non-static key. [ 36.068892] the code is fine but needs lockdep annotation. [ 36.068894] turning off the locking correctness validator. [ 36.068903] CPU: 1 PID: 2836 Comm: syz-executor473 Not tainted 4.4.172+ #13 [ 36.068913] 0000000000000000 3868140d34f89ae0 ffff8801ce9e76a0 ffffffff81aacde1 [ 36.068921] ffffffff83a710c0 ffff8801d32f17c0 0000000000000000 0000000000000001 [ 36.068928] 0000000000000000 ffff8801ce9e7830 ffffffff8120372e ffff8801d32f17c0 [ 36.068930] Call Trace: [ 36.068945] [] dump_stack+0xc1/0x120 [ 36.068955] [] __lock_acquire+0x438e/0x4f50 [ 36.068965] [] ? quarantine_put+0xda/0x180 [ 36.068971] [] ? trace_hardirqs_on+0x10/0x10 [ 36.068977] [] ? trace_hardirqs_on+0x10/0x10 [ 36.068983] [] ? trace_hardirqs_on_caller+0x385/0x5a0 [ 36.068993] [] ? mutex_lock_nested+0x645/0xb80 [ 36.069000] [] ? blkdev_put+0x2b/0x560 [ 36.069009] [] ? get_signal+0x517/0x1570 [ 36.069017] [] ? do_signal+0x9c/0x1840 [ 36.069027] [] ? exit_to_usermode_loop+0x127/0x170 [ 36.069035] [] ? sysenter_flags_fixed+0xd/0x1a [ 36.069041] [] lock_acquire+0x15e/0x450 [ 36.069051] [] ? disk_flush_events+0x57/0x140 [ 36.069057] [] _raw_spin_lock_irq+0x44/0x60 [ 36.069064] [] ? disk_flush_events+0x57/0x140 [ 36.069070] [] disk_flush_events+0x57/0x140 [ 36.069075] [] blkdev_put+0x73/0x560 [ 36.069081] [] ? blkdev_put+0x560/0x560 [ 36.069086] [] blkdev_close+0x8b/0xb0 [ 36.069095] [] __fput+0x246/0x710 [ 36.069101] [] ____fput+0x16/0x20 [ 36.069110] [] task_work_run+0x202/0x2b0 [ 36.069118] [] do_exit+0x8ea/0x2a50 [ 36.069125] [] ? quarantine_put+0xda/0x180 [ 36.069132] [] ? release_task+0x14a0/0x14a0 [ 36.069140] [] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 36.069146] [] ? recalc_sigpending+0x74/0xa0 [ 36.069152] [] ? dequeue_signal+0xc8/0x550 [ 36.069160] [] ? check_preemption_disabled+0x3c/0x200 [ 36.069166] [] do_group_exit+0x111/0x300 [ 36.069172] [] get_signal+0x517/0x1570 [ 36.069179] [] ? _raw_spin_unlock_irqrestore+0x5a/0x70 [ 36.069186] [] do_signal+0x9c/0x1840 [ 36.069192] [] ? check_preemption_disabled+0x3c/0x200 [ 36.069198] [] ? check_preemption_disabled+0x3c/0x200 [ 36.069203] [] ? setup_sigcontext+0x780/0x780 [ 36.069210] [] ? putname+0xdb/0x120 [ 36.069216] [] ? rcu_read_lock_sched_held+0x10b/0x130 [ 36.069222] [] ? kmem_cache_free+0x2c4/0x350 [ 36.069228] [] ? do_sys_open+0x237/0x600 [ 36.069234] [] ? filp_open+0x70/0x70 [ 36.069243] [] ? exit_to_usermode_loop+0xf2/0x170 [ 36.069250] [] exit_to_usermode_loop+0x127/0x170 [ 36.069258] [] do_fast_syscall_32+0x7a9/0xa90 [ 36.069265] [] sysenter_flags_fixed+0xd/0x1a [ 36.069273] ------------[ cut here ]------------ [ 36.069282] WARNING: CPU: 1 PID: 2836 at lib/debugobjects.c:260 debug_print_object+0x181/0x210() [ 36.069291] ODEBUG: assert_init not available (active state 0) object type: timer_list hint: stub_timer+0x0/0x20 [ 36.069295] Kernel panic - not syncing: panic_on_warn set ... [ 36.069295] [ 36.069302] CPU: 1 PID: 2836 Comm: syz-executor473 Not tainted 4.4.172+ #13 [ 36.069311] 0000000000000000 3868140d34f89ae0 ffff8801ce9e73e8 ffffffff81aacde1 [ 36.069318] ffff8801ce9e7538 ffffffff82835ee0 ffffffff8292c440 0000000000000104 [ 36.069326] ffffffff81b0afe1 ffff8801ce9e74c8 ffffffff813a46b2 0000000041b58ab3 [ 36.069327] Call Trace: [ 36.069338] [] dump_stack+0xc1/0x120 [ 36.069343] [] ? debug_print_object+0x181/0x210 [ 36.069353] [] panic+0x1b9/0x37b [ 36.069359] [] ? add_taint.cold+0x16/0x16 [ 36.069366] [] ? console_trylock+0x2c/0xc0 [ 36.069372] [] ? vprintk_emit+0x248/0x820 [ 36.069380] [] ? warn_slowpath_common.cold+0x5/0x20 [ 36.069398] [] warn_slowpath_common.cold+0x20/0x20 [ 36.069405] [] ? _raw_spin_unlock_irqrestore+0x45/0x70 [ 36.069413] [] ? __internal_add_timer+0x240/0x240 [ 36.069420] [] warn_slowpath_fmt+0xbf/0x100 [ 36.069426] [] ? warn_slowpath_common+0x120/0x120 [ 36.069433] [] ? check_memory_region+0x114/0x180 [ 36.069439] [] debug_print_object+0x181/0x210 [ 36.069446] [] ? trace_event_raw_event_tick_stop+0x280/0x280 [ 36.069453] [] ? __asan_report_store8_noabort+0x17/0x20 [ 36.069459] [] debug_object_assert_init+0x229/0x2d0 [ 36.069465] [] ? debug_object_free+0x350/0x350 [ 36.069472] [] ? quarantine_put+0xda/0x180 [ 36.069478] [] del_timer+0x7c/0x1b0 [ 36.069485] [] ? trace_hardirqs_on+0x10/0x10 [ 36.069491] [] ? del_timer_sync+0x140/0x140 [ 36.069496] [] ? trace_hardirqs_on+0x10/0x10 [ 36.069503] [] ? trace_hardirqs_on_caller+0x385/0x5a0 [ 36.069510] [] try_to_grab_pending+0x1d1/0x530 [ 36.069518] [] ? exit_to_usermode_loop+0x127/0x170 [ 36.069524] [] mod_delayed_work_on+0x92/0x140 [ 36.069530] [] ? queue_delayed_work_on+0xb0/0xb0 [ 36.069539] [] disk_flush_events+0x10b/0x140 [ 36.069545] [] blkdev_put+0x73/0x560 [ 36.069550] [] ? blkdev_put+0x560/0x560 [ 36.069555] [] blkdev_close+0x8b/0xb0 [ 36.069563] [] __fput+0x246/0x710 [ 36.069569] [] ____fput+0x16/0x20 [ 36.069575] [] task_work_run+0x202/0x2b0 [ 36.069583] [] do_exit+0x8ea/0x2a50 [ 36.069589] [] ? quarantine_put+0xda/0x180 [ 36.069596] [] ? release_task+0x14a0/0x14a0 [ 36.069602] [] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 36.069609] [] ? recalc_sigpending+0x74/0xa0 [ 36.069615] [] ? dequeue_signal+0xc8/0x550 [ 36.069621] [] ? check_preemption_disabled+0x3c/0x200 [ 36.069627] [] do_group_exit+0x111/0x300 [ 36.069633] [] get_signal+0x517/0x1570 [ 36.069640] [] ? _raw_spin_unlock_irqrestore+0x5a/0x70 [ 36.069646] [] do_signal+0x9c/0x1840 [ 36.069652] [] ? check_preemption_disabled+0x3c/0x200 [ 36.069658] [] ? check_preemption_disabled+0x3c/0x200 [ 36.069663] [] ? setup_sigcontext+0x780/0x780 [ 36.069671] [] ? putname+0xdb/0x120 [ 36.069677] [] ? rcu_read_lock_sched_held+0x10b/0x130 [ 36.069691] [] ? kmem_cache_free+0x2c4/0x350 [ 36.069698] [] ? do_sys_open+0x237/0x600 [ 36.069703] [] ? filp_open+0x70/0x70 [ 36.069710] [] ? exit_to_usermode_loop+0xf2/0x170 [ 36.069717] [] exit_to_usermode_loop+0x127/0x170 [ 36.069725] [] do_fast_syscall_32+0x7a9/0xa90 [ 36.069733] [] sysenter_flags_fixed+0xd/0x1a [ 37.238383] Shutting down cpus with NMI [ 37.239083] Kernel Offset: disabled [ 38.038683] Rebooting in 86400 seconds..