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AAOMgpdQIlpifRbwXXS8DefK2PqXVwxGd3TEC3I9l3aGskiS610tQ6XqYLcJuUDzhN+TEvYXqs8rew== X-Received: by 2002:a6b:a58f:: with SMTP id o137-v6mr18164418ioe.63.1530557432295; Mon, 02 Jul 2018 11:50:32 -0700 (PDT) Received: from [192.168.86.235] ([184.63.162.180]) by smtp.gmail.com with ESMTPSA id e18-v6sm1213717iof.23.2018.07.02.11.50.17 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 02 Jul 2018 11:50:31 -0700 (PDT) Subject: Re: WARNING: ODEBUG bug in sock_hash_free To: syzbot , ast@kernel.org, daniel@iogearbox.net, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com References: <00000000000037c7d5056f84cabc@google.com> From: John Fastabend Message-ID: Date: Mon, 2 Jul 2018 11:48:56 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <00000000000037c7d5056f84cabc@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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@syzkaller.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@googlegroups.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