On Sat, 22 Feb 2020 10:58:12 -0800 > syzbot found the following crash on: > > HEAD commit: 2bb07f4e tc-testing: updated tdc tests for basic filter > git tree: net-next > console output: https://syzkaller.appspot.com/x/log.txt?x=122efdede00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=768cc3d3e277cc16 > dashboard link: https://syzkaller.appspot.com/bug?extid=731710996d79d0d58fbc > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14887de9e00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=149eec81e00000 > > The bug was bisected to: > > commit 408624af4c89989117bb2c6517bd50b7708a2fcd > Author: Stefano Garzarella <sgarzare@xxxxxxxxxx> > Date: Tue Dec 10 10:43:06 2019 +0000 > > vsock: use local transport when it is loaded > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1011e27ee00000 > final crash: https://syzkaller.appspot.com/x/report.txt?x=1211e27ee00000 > console output: https://syzkaller.appspot.com/x/log.txt?x=1411e27ee00000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+731710996d79d0d58fbc@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: 408624af4c89 ("vsock: use local transport when it is loaded") > > INFO: task syz-executor280:9768 blocked for more than 143 seconds. > Not tainted 5.6.0-rc1-syzkaller #0 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > syz-executor280 D27912 9768 9766 0x00000000 > Call Trace: > context_switch kernel/sched/core.c:3386 [inline] > __schedule+0x934/0x1f90 kernel/sched/core.c:4082 > schedule+0xdc/0x2b0 kernel/sched/core.c:4156 > __lock_sock+0x165/0x290 net/core/sock.c:2413 > lock_sock_nested+0xfe/0x120 net/core/sock.c:2938 > virtio_transport_release+0xc4/0xd60 net/vmw_vsock/virtio_transport_common.c:832 > vsock_assign_transport+0xf3/0x3b0 net/vmw_vsock/af_vsock.c:454 > vsock_stream_connect+0x2b3/0xc70 net/vmw_vsock/af_vsock.c:1288 > __sys_connect_file+0x161/0x1c0 net/socket.c:1857 > __sys_connect+0x174/0x1b0 net/socket.c:1874 > __do_sys_connect net/socket.c:1885 [inline] > __se_sys_connect net/socket.c:1882 [inline] > __x64_sys_connect+0x73/0xb0 net/socket.c:1882 > do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x440209 > Code: Bad RIP value. > RSP: 002b:00007ffdb9f67718 EFLAGS: 00000246 ORIG_RAX: 000000000000002a > RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440209 > RDX: 0000000000000010 RSI: 0000000020000440 RDI: 0000000000000003 > RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 > R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000401a90 > R13: 0000000000401b20 R14: 0000000000000000 R15: 0000000000000000 > > Showing all locks held in the system: > 1 lock held by khungtaskd/951: > #0: ffffffff89bac240 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5333 > 1 lock held by rsyslogd/9652: > #0: ffff8880a6533120 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:821 > 2 locks held by getty/9742: > #0: ffff8880a693f090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 > #1: ffffc900061bb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 > 2 locks held by getty/9743: > #0: ffff88809f7a1090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 > #1: ffffc900061b72e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 > 2 locks held by getty/9744: > #0: ffff88809be3e090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 > #1: ffffc900061632e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 > 2 locks held by getty/9745: > #0: ffff88808eb1e090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 > #1: ffffc900061bf2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 > 2 locks held by getty/9746: > #0: ffff88808d33a090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 > #1: ffffc900061732e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 > 2 locks held by getty/9747: > #0: ffff8880a6a0c090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 > #1: ffffc900061c32e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 > 2 locks held by getty/9748: > #0: ffff8880a6e4d090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 > #1: ffffc900061332e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 > 1 lock held by syz-executor280/9768: > #0: ffff8880987cb8d0 (sk_lock-AF_VSOCK){+.+.}, at: lock_sock include/net/sock.h:1516 [inline] > #0: ffff8880987cb8d0 (sk_lock-AF_VSOCK){+.+.}, at: vsock_stream_connect+0xfb/0xc70 net/vmw_vsock/af_vsock.c:1258 > > ============================================= > > NMI backtrace for cpu 1 > CPU: 1 PID: 951 Comm: khungtaskd Not tainted 5.6.0-rc1-syzkaller #0 > 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+0x197/0x210 lib/dump_stack.c:118 > nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 > nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 > arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 > trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] > check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] > watchdog+0xb11/0x10c0 kernel/hung_task.c:289 > kthread+0x361/0x430 kernel/kthread.c:255 > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 > Sending NMI from CPU 1 to CPUs 0: > NMI backtrace for cpu 0 > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc1-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:group_is_overloaded kernel/sched/fair.c:7929 [inline] > RIP: 0010:group_classify kernel/sched/fair.c:7964 [inline] > RIP: 0010:update_sg_lb_stats kernel/sched/fair.c:8077 [inline] > RIP: 0010:update_sd_lb_stats kernel/sched/fair.c:8565 [inline] > RIP: 0010:find_busiest_group+0xa33/0x3250 kernel/sched/fair.c:8793 > Code: 89 f8 83 e0 07 83 c0 03 40 38 f0 7c 09 40 84 f6 0f 85 f7 1f 00 00 48 8b b5 c0 fd ff ff 41 8b 41 2c 48 c1 ee 03 42 0f b6 34 26 <40> 84 f6 74 0a 40 80 fe 03 0f 8e 8f 1f 00 00 44 8b 6b 20 44 39 ea > RSP: 0018:ffffc90000007850 EFLAGS: 00000a06 > RAX: 000000000000006e RBX: ffffc90000007938 RCX: 00000000000003fa > RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff8880a9a8282c > RBP: ffffc90000007af0 R08: ffffffff89a7a440 R09: ffff8880a9a82800 > R10: 0000000000000000 R11: ffff8880a9a83f27 R12: dffffc0000000000 > R13: ffff8880a9a83e80 R14: ffffc90000007ac8 R15: ffffc90000007c08 > FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffffffffff600400 CR3: 000000009fde0000 CR4: 00000000001406f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <IRQ> > load_balance+0x38c/0x2b50 kernel/sched/fair.c:9161 > rebalance_domains+0x739/0x1000 kernel/sched/fair.c:9588 > _nohz_idle_balance+0x336/0x3f0 kernel/sched/fair.c:10002 > nohz_idle_balance kernel/sched/fair.c:10048 [inline] > run_rebalance_domains+0x1c6/0x2d0 kernel/sched/fair.c:10237 > __do_softirq+0x262/0x98c kernel/softirq.c:292 > invoke_softirq kernel/softirq.c:373 [inline] > irq_exit+0x19b/0x1e0 kernel/softirq.c:413 > scheduler_ipi+0x38c/0x610 kernel/sched/core.c:2349 > smp_reschedule_interrupt+0x78/0x4c0 arch/x86/kernel/smp.c:244 > reschedule_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:853 > </IRQ> > RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61 > Code: 58 f5 c3 f9 eb 8a cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 74 40 58 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 64 40 58 00 fb f4 <c3> cc 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 ce ac 72 f9 e8 e9 > RSP: 0018:ffffffff89a07ce8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02 > RAX: 1ffffffff136761a RBX: ffffffff89a7a440 RCX: 0000000000000000 > RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffffffff89a7acd4 > RBP: ffffffff89a07d18 R08: ffffffff89a7a440 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 > R13: ffffffff8aa5ab80 R14: 0000000000000000 R15: 0000000000000000 > arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:686 > default_idle_call+0x84/0xb0 kernel/sched/idle.c:94 > cpuidle_idle_call kernel/sched/idle.c:154 [inline] > do_idle+0x3c8/0x6e0 kernel/sched/idle.c:269 > cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361 > rest_init+0x23b/0x371 init/main.c:654 > arch_call_rest_init+0xe/0x1b > start_kernel+0x886/0x8c5 init/main.c:992 > x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490 > x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:471 > secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242 > > > --- > 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@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches Seems like vsock needs a word to track lock owner in an attempt to avoid trying to lock sock while the current is the lock owner. --- a/include/net/af_vsock.h +++ b/include/net/af_vsock.h @@ -41,6 +41,7 @@ struct vsock_sock { * cached peer? */ u32 cached_peer; /* Context ID of last dgram destination check. */ + void *lock_owner; const struct cred *owner; /* Rest are SOCK_STREAM only. */ long connect_timeout; @@ -74,6 +75,13 @@ struct vsock_sock { void *trans; }; +static inline bool vsock_locked(struct sock *sk) +{ + struct vsock_sock *vsk = vsock_sk(sk); + + return vsk->lock_owner == current; +} + s64 vsock_stream_has_data(struct vsock_sock *vsk); s64 vsock_stream_has_space(struct vsock_sock *vsk); struct sock *vsock_create_connected(struct sock *parent); --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -1236,6 +1236,7 @@ static int vsock_stream_connect(struct s vsk = vsock_sk(sk); lock_sock(sk); + vsk->lock_owner = current; /* XXX AF_UNSPEC should make us disconnect like AF_INET. */ switch (sock->state) { @@ -1320,9 +1321,11 @@ static int vsock_stream_connect(struct s goto out_wait; } + vsk->lock_owner = NULL; release_sock(sk); timeout = schedule_timeout(timeout); lock_sock(sk); + vsk->lock_owner = current; if (signal_pending(current)) { err = sock_intr_errno(timeout); @@ -1352,6 +1355,7 @@ static int vsock_stream_connect(struct s out_wait: finish_wait(sk_sleep(sk), &wait); out: + vsk->lock_owner = NULL; release_sock(sk); return err; } --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -832,7 +832,9 @@ void virtio_transport_release(struct vso struct sock *sk = &vsk->sk; bool remove_sock = true; - lock_sock_nested(sk, SINGLE_DEPTH_NESTING); + if (!vsock_locked(sk)) + lock_sock_nested(sk, SINGLE_DEPTH_NESTING); + if (sk->sk_type == SOCK_STREAM) remove_sock = virtio_transport_close(vsk); @@ -840,7 +842,9 @@ void virtio_transport_release(struct vso list_del(&pkt->list); virtio_transport_free_pkt(pkt); } - release_sock(sk); + + if (!vsock_locked(sk)) + release_sock(sk); if (remove_sock) vsock_remove_sock(vsk); _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
