syzbot


WARNING: ODEBUG bug in sock_hash_free

Status: fixed on 2018/07/09 18:05
Subsystems: bpf
[Documentation on labels]
Reported-by: syzbot+71aeaaf993d216185076@syzkaller.appspotmail.com
Fix commit: e9db4ef6bf4c bpf: sockhash fix omitted bucket lock in sock_close
First crash: 2220d, last: 2220d
Discussions (1)
Title Replies (including bot) Last reply
WARNING: ODEBUG bug in sock_hash_free 1 (2) 2018/07/02 18:48

Sample crash report:
------------[ cut here ]------------
ODEBUG: free active (active state 1) object type: rcu_head hint:           (null)
WARNING: CPU: 1 PID: 4959 at lib/debugobjects.c:329 debug_print_object+0x16a/0x210 lib/debugobjects.c:326
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4959 Comm: kworker/1:3 Not tainted 4.17.0+ #39
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events bpf_map_free_deferred
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 panic+0x22f/0x4de kernel/panic.c:184
 __warn.cold.8+0x163/0x1b3 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: 1a 88 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 92 00 00 00 48 8b 14 dd 60 75 1a 88 4c 89 f6 48 c7 c7 e0 6a 1a 88 e8 06 62 ec fd <0f> 0b 83 05 39 5b 44 06 01 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 
RSP: 0018:ffff880198e47490 EFLAGS: 00010082
RAX: 0000000000000051 RBX: 0000000000000003 RCX: ffffffff81854ed8
RDX: 0000000000000000 RSI: ffffffff8161f371 RDI: 0000000000000001
RBP: ffff880198e474d0 R08: ffff8801d84b2240 R09: ffffed003b5e3ec2
R10: ffffed003b5e3ec2 R11: ffff8801daf1f617 R12: 0000000000000001
R13: ffffffff88f91d80 R14: ffffffff881a6f80 R15: 0000000000000000
 __debug_check_no_obj_freed lib/debugobjects.c:783 [inline]
 debug_check_no_obj_freed+0x3a6/0x584 lib/debugobjects.c:815
 kfree+0xc7/0x260 mm/slab.c:3812
 sock_hash_free+0x24e/0x6e0 kernel/bpf/sockmap.c:2093
 bpf_map_free_deferred+0xba/0xf0 kernel/bpf/syscall.c:262
 process_one_work+0xc64/0x1b70 kernel/workqueue.c:2153
 worker_thread+0x181/0x13a0 kernel/workqueue.c:2296
 kthread+0x345/0x410 kernel/kthread.c:240
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

======================================================
WARNING: possible circular locking dependency detected
4.17.0+ #39 Not tainted
------------------------------------------------------
kworker/1:3/4959 is trying to acquire lock:
00000000190110fa ((console_sem).lock){-...}, at: down_trylock+0x13/0x70 kernel/locking/semaphore.c:136

but task is already holding lock:
00000000af3150e8 (&obj_hash[i].lock){-.-.}, at: __debug_check_no_obj_freed lib/debugobjects.c:774 [inline]
00000000af3150e8 (&obj_hash[i].lock){-.-.}, at: debug_check_no_obj_freed+0x159/0x584 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+0x11f/0x12c0 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+0x8f/0x460 kernel/time/hrtimer.c:1308
       init_dl_task_timer+0x1b/0x50 kernel/sched/deadline.c:1056
       __sched_fork+0x2a8/0x570 kernel/sched/core.c:2184
       init_idle+0x75/0x7a0 kernel/sched/core.c:5404
       sched_init+0xbeb/0xd10 kernel/sched/core.c:6102
       start_kernel+0x475/0x92d 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:1805 [inline]
       task_fork_fair+0x8a/0x660 kernel/sched/fair.c:9953
       sched_fork+0x43e/0xb30 kernel/sched/core.c:2380
       copy_process.part.38+0x1bf1/0x7180 kernel/fork.c:1765
       copy_process kernel/fork.c:1608 [inline]
       _do_fork+0x291/0x12a0 kernel/fork.c:2091
       kernel_thread+0x34/0x40 kernel/fork.c:2150
       rest_init+0x22/0xe4 init/main.c:408
       start_kernel+0x906/0x92d 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+0xca/0x1280 kernel/sched/core.c:1984
       wake_up_process+0x10/0x20 kernel/sched/core.c:2147
       __up.isra.1+0x1b8/0x290 kernel/locking/semaphore.c:262
       up+0x12f/0x1b0 kernel/locking/semaphore.c:187
       __up_console_sem+0xbe/0x1b0 kernel/printk/printk.c:242
       console_unlock+0x79a/0x10a0 kernel/printk/printk.c:2411
       vprintk_emit+0x6b2/0xde0 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+0x9e/0xba kernel/printk/printk.c:1981
       load_umh+0x51/0xbd net/bpfilter/bpfilter_kern.c:99
       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+0x1dc/0x520 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+0x699/0xde0 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+0x9e/0xba kernel/printk/printk.c:1981
       __warn_printk+0x83/0xd0 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+0x3a6/0x584 lib/debugobjects.c:815
       kfree+0xc7/0x260 mm/slab.c:3812
       sock_hash_free+0x24e/0x6e0 kernel/bpf/sockmap.c:2093
       bpf_map_free_deferred+0xba/0xf0 kernel/bpf/syscall.c:262
       process_one_work+0xc64/0x1b70 kernel/workqueue.c:2153
       worker_thread+0x181/0x13a0 kernel/workqueue.c:2296
       kthread+0x345/0x410 kernel/kthread.c:240
       ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

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 ***

4 locks held by kworker/1:3/4959:
 #0: 00000000f67deee4 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline]
 #0: 00000000f67deee4 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000f67deee4 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000f67deee4 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
 #0: 00000000f67deee4 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000f67deee4 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000f67deee4 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb35/0x1b70 kernel/workqueue.c:2124
 #1: 00000000776b40d0 ((work_completion)(&map->work)){+.+.}, at: process_one_work+0xb8c/0x1b70 kernel/workqueue.c:2128
 #2: 000000002a359661 (rcu_read_lock){....}, at: sock_hash_free+0x0/0x6e0 include/net/sock.h:2176
 #3: 00000000af3150e8 (&obj_hash[i].lock){-.-.}, at: __debug_check_no_obj_freed lib/debugobjects.c:774 [inline]
 #3: 00000000af3150e8 (&obj_hash[i].lock){-.-.}, at: debug_check_no_obj_freed+0x159/0x584 lib/debugobjects.c:815

stack backtrace:
CPU: 1 PID: 4959 Comm: kworker/1:3 Not tainted 4.17.0+ #39
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events bpf_map_free_deferred
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 print_circular_bug.isra.36.cold.56+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+0x343e/0x5140 kernel/locking/lockdep.c:3435
 lock_acquire+0x1dc/0x520 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+0x699/0xde0 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+0x9e/0xba kernel/printk/printk.c:1981
 __warn_printk+0x83/0xd0 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+0x3a6/0x584 lib/debugobjects.c:815
 kfree+0xc7/0x260 mm/slab.c:3812
 sock_hash_free+0x24e/0x6e0 kernel/bpf/sockmap.c:2093
 bpf_map_free_deferred+0xba/0xf0 kernel/bpf/syscall.c:262
 process_one_work+0xc64/0x1b70 kernel/workqueue.c:2153
 worker_thread+0x181/0x13a0 kernel/workqueue.c:2296
 kthread+0x345/0x410 kernel/kthread.c:240
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412
Shutting down cpus with NMI
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/06/25 16:30 bpf-next f0dc7f9c6dd9 2064fc5c .config console log report ci-upstream-bpf-next-kasan-gce
* Struck through repros no longer work on HEAD.