------------[ cut here ]------------ ODEBUG: free active (active state 0) object type: work_struct hint: p9_read_work+0x0/0x1060 net/9p/trans_fd.c:208 WARNING: CPU: 0 PID: 22628 at lib/debugobjects.c:329 debug_print_object+0x16a/0x210 lib/debugobjects.c:326 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 22628 Comm: syz-executor0 Not tainted 4.18.0-rc6+ #168 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 panic+0x238/0x4e7 kernel/panic.c:184 __warn.cold.8+0x163/0x1ba kernel/panic.c:536 report_bug+0x252/0x2d0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992 RIP: 0010:debug_print_object+0x16a/0x210 lib/debugobjects.c:326 Code: 3a 87 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 92 00 00 00 48 8b 14 dd 20 74 3a 87 4c 89 f6 48 c7 c7 c0 69 3a 87 e8 a6 b0 e6 fd <0f> 0b 83 05 89 e6 29 05 01 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffff8801929df2d8 EFLAGS: 00010086 RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffffc90001e14000 RDX: 000000000002fb8a RSI: ffffffff81632531 RDI: 0000000000000001 RBP: ffff8801929df318 R08: ffff8801ade94000 R09: ffffed003b603ec2 R10: ffffed003b603ec2 R11: ffff8801db01f617 R12: 0000000000000001 R13: ffffffff87f638a0 R14: ffffffff873a6e60 R15: ffffffff814eac90 __debug_check_no_obj_freed lib/debugobjects.c:783 [inline] debug_check_no_obj_freed+0x3b2/0x595 lib/debugobjects.c:815 kfree+0xc7/0x260 mm/slab.c:3812 p9_fd_close+0x416/0x5b0 net/9p/trans_fd.c:893 p9_client_create+0xa9a/0x1770 net/9p/client.c:1077 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135 mount_fs+0xae/0x328 fs/super.c:1277 vfs_kern_mount.part.34+0xdc/0x4e0 fs/namespace.c:1037 vfs_kern_mount fs/namespace.c:1027 [inline] do_new_mount fs/namespace.c:2518 [inline] do_mount+0x581/0x30e0 fs/namespace.c:2848 ksys_mount+0x12d/0x140 fs/namespace.c:3064 __do_sys_mount fs/namespace.c:3078 [inline] __se_sys_mount fs/namespace.c:3075 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x456a09 Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f558ac62c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f558ac636d4 RCX: 0000000000456a09 RDX: 0000000020000180 RSI: 00000000200000c0 RDI: 0000000020000000 RBP: 00000000009300a0 R08: 0000000020000140 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d1798 R14: 00000000004c6ea6 R15: 0000000000000000 ====================================================== WARNING: possible circular locking dependency detected 4.18.0-rc6+ #168 Not tainted ------------------------------------------------------ syz-executor0/22628 is trying to acquire lock: 0000000050b1d9b2 ((console_sem).lock){-.-.}, at: down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 but task is already holding lock: 0000000027780c6f (&obj_hash[i].lock){-.-.}, at: __debug_check_no_obj_freed lib/debugobjects.c:774 [inline] 0000000027780c6f (&obj_hash[i].lock){-.-.}, at: debug_check_no_obj_freed+0x16c/0x595 lib/debugobjects.c:815 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&obj_hash[i].lock){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152 __debug_object_init+0x127/0x12e0 lib/debugobjects.c:381 debug_object_init+0x16/0x20 lib/debugobjects.c:429 debug_hrtimer_init kernel/time/hrtimer.c:410 [inline] debug_init kernel/time/hrtimer.c:458 [inline] hrtimer_init+0x97/0x480 kernel/time/hrtimer.c:1308 init_dl_task_timer+0x1b/0x50 kernel/sched/deadline.c:1056 __sched_fork+0x2ae/0x590 kernel/sched/core.c:2185 init_idle+0x75/0x7a0 kernel/sched/core.c:5405 sched_init+0xbf3/0xd2c kernel/sched/core.c:6103 start_kernel+0x47d/0x949 init/main.c:602 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:452 x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:433 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:242 -> #2 (&rq->lock){-.-.}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144 rq_lock kernel/sched/sched.h:1812 [inline] task_fork_fair+0x93/0x680 kernel/sched/fair.c:9952 sched_fork+0x446/0xb40 kernel/sched/core.c:2381 copy_process.part.39+0x1bf5/0x70b0 kernel/fork.c:1796 copy_process kernel/fork.c:1639 [inline] _do_fork+0x291/0x12a0 kernel/fork.c:2122 kernel_thread+0x34/0x40 kernel/fork.c:2181 rest_init+0x22/0xe4 init/main.c:408 start_kernel+0x90e/0x949 init/main.c:738 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:452 x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:433 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:242 -> #1 (&p->pi_lock){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152 try_to_wake_up+0xd2/0x12a0 kernel/sched/core.c:1985 wake_up_process+0x10/0x20 kernel/sched/core.c:2148 __up.isra.1+0x1c0/0x2a0 kernel/locking/semaphore.c:262 up+0x13c/0x1c0 kernel/locking/semaphore.c:187 __up_console_sem+0xbe/0x1b0 kernel/printk/printk.c:242 console_unlock+0x7a2/0x10b0 kernel/printk/printk.c:2411 vprintk_emit+0x6c6/0xdf0 kernel/printk/printk.c:1907 vprintk_default+0x28/0x30 kernel/printk/printk.c:1948 vprintk_func+0x7a/0xe7 kernel/printk/printk_safe.c:382 printk+0xa7/0xcf kernel/printk/printk.c:1981 load_umh+0x51/0xbd net/bpfilter/bpfilter_kern.c:98 do_one_initcall+0x127/0x913 init/main.c:884 do_initcall_level init/main.c:952 [inline] do_initcalls init/main.c:960 [inline] do_basic_setup init/main.c:978 [inline] kernel_init_freeable+0x49b/0x58e init/main.c:1135 kernel_init+0x11/0x1b3 init/main.c:1061 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 -> #0 ((console_sem).lock){-.-.}: lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152 down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 __down_trylock_console_sem+0xae/0x200 kernel/printk/printk.c:225 console_trylock+0x15/0xa0 kernel/printk/printk.c:2230 console_trylock_spinning kernel/printk/printk.c:1643 [inline] vprintk_emit+0x6ad/0xdf0 kernel/printk/printk.c:1906 vprintk_default+0x28/0x30 kernel/printk/printk.c:1948 vprintk_func+0x7a/0xe7 kernel/printk/printk_safe.c:382 printk+0xa7/0xcf kernel/printk/printk.c:1981 __warn_printk+0x8c/0xe0 kernel/panic.c:590 debug_print_object+0x16a/0x210 lib/debugobjects.c:326 __debug_check_no_obj_freed lib/debugobjects.c:783 [inline] debug_check_no_obj_freed+0x3b2/0x595 lib/debugobjects.c:815 kfree+0xc7/0x260 mm/slab.c:3812 p9_fd_close+0x416/0x5b0 net/9p/trans_fd.c:893 p9_client_create+0xa9a/0x1770 net/9p/client.c:1077 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135 mount_fs+0xae/0x328 fs/super.c:1277 vfs_kern_mount.part.34+0xdc/0x4e0 fs/namespace.c:1037 vfs_kern_mount fs/namespace.c:1027 [inline] do_new_mount fs/namespace.c:2518 [inline] do_mount+0x581/0x30e0 fs/namespace.c:2848 ksys_mount+0x12d/0x140 fs/namespace.c:3064 __do_sys_mount fs/namespace.c:3078 [inline] __se_sys_mount fs/namespace.c:3075 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: (console_sem).lock --> &rq->lock --> &obj_hash[i].lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&obj_hash[i].lock); lock(&rq->lock); lock(&obj_hash[i].lock); lock((console_sem).lock); *** DEADLOCK *** 1 lock held by syz-executor0/22628: #0: 0000000027780c6f (&obj_hash[i].lock){-.-.}, at: __debug_check_no_obj_freed lib/debugobjects.c:774 [inline] #0: 0000000027780c6f (&obj_hash[i].lock){-.-.}, at: debug_check_no_obj_freed+0x16c/0x595 lib/debugobjects.c:815 stack backtrace: CPU: 0 PID: 22628 Comm: syz-executor0 Not tainted 4.18.0-rc6+ #168 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 print_circular_bug.isra.36.cold.57+0x1bd/0x27d kernel/locking/lockdep.c:1227 check_prev_add kernel/locking/lockdep.c:1867 [inline] check_prevs_add kernel/locking/lockdep.c:1980 [inline] validate_chain kernel/locking/lockdep.c:2421 [inline] __lock_acquire+0x3449/0x5020 kernel/locking/lockdep.c:3435 lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152 down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 __down_trylock_console_sem+0xae/0x200 kernel/printk/printk.c:225 console_trylock+0x15/0xa0 kernel/printk/printk.c:2230 console_trylock_spinning kernel/printk/printk.c:1643 [inline] vprintk_emit+0x6ad/0xdf0 kernel/printk/printk.c:1906 vprintk_default+0x28/0x30 kernel/printk/printk.c:1948 vprintk_func+0x7a/0xe7 kernel/printk/printk_safe.c:382 printk+0xa7/0xcf kernel/printk/printk.c:1981 __warn_printk+0x8c/0xe0 kernel/panic.c:590 debug_print_object+0x16a/0x210 lib/debugobjects.c:326 __debug_check_no_obj_freed lib/debugobjects.c:783 [inline] debug_check_no_obj_freed+0x3b2/0x595 lib/debugobjects.c:815 kfree+0xc7/0x260 mm/slab.c:3812 p9_fd_close+0x416/0x5b0 net/9p/trans_fd.c:893 p9_client_create+0xa9a/0x1770 net/9p/client.c:1077 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135 mount_fs+0xae/0x328 fs/super.c:1277 vfs_kern_mount.part.34+0xdc/0x4e0 fs/namespace.c:1037 vfs_kern_mount fs/namespace.c:1027 [inline] do_new_mount fs/namespace.c:2518 [inline] do_mount+0x581/0x30e0 fs/namespace.c:2848 ksys_mount+0x12d/0x140 fs/namespace.c:3064 __do_sys_mount fs/namespace.c:3078 [inline] __se_sys_mount fs/namespace.c:3075 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x456a09 Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f558ac62c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f558ac636d4 RCX: 0000000000456a09 RDX: 0000000020000180 RSI: 00000000200000c0 RDI: 0000000020000000 RBP: 00000000009300a0 R08: 0000000020000140 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d1798 R14: 00000000004c6ea6 R15: 0000000000000000 Shutting down cpus with NMI Dumping ftrace buffer: (ftrace buffer empty) Kernel Offset: disabled Rebooting in 86400 seconds..