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Message-ID: <a5b01be4-e11c-58a8-2199-9b4faab8a3e3@gmail.com>
Date: Mon, 2 Jul 2018 11:48:56 -0700
From: John Fastabend <john.fastabend@...il.com>
To: syzbot <syzbot+71aeaaf993d216185076@...kaller.appspotmail.com>,
ast@...nel.org, daniel@...earbox.net, linux-kernel@...r.kernel.org,
netdev@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: WARNING: ODEBUG bug in sock_hash_free
On 06/25/2018 10:30 PM, syzbot wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: f0dc7f9c6dd9 Merge git://git.kernel.org/pub/scm/linux/kern..
> git tree: bpf-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1725589f800000
> kernel config: https://syzkaller.appspot.com/x/.config?x=fa9c20c48788d1c1
> dashboard link: https://syzkaller.appspot.com/bug?extid=71aeaaf993d216185076
> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
>
> Unfortunately, I don't have any reproducer for this crash yet.
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+71aeaaf993d216185076@...kaller.appspotmail.com
>
> ------------[ 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..
>
>
> ---
> This bug is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@...glegroups.com.
>
> syzbot will keep track of this bug report. See:
> https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot.
#syz fix: bpf: sockhash fix omitted bucket lock in sock_close
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