syzbot


INFO: task hung in namespace_unlock

Status: auto-closed as invalid on 2019/12/17 06:15
Reported-by: syzbot+50fb0a159636e2ec7686@syzkaller.appspotmail.com
First crash: 1921d, last: 1706d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-414 INFO: task hung in namespace_unlock 1 1940d 1836d 0/1 auto-closed as invalid on 2019/06/26 03:51
upstream INFO: task hung in namespace_unlock (2) kernel 9 1737d 1909d 0/26 auto-closed as invalid on 2019/10/25 14:11
upstream INFO: task hung in namespace_unlock fs 15 2115d 2124d 8/26 fixed on 2018/07/09 18:05

Sample crash report:
   Free memory is -14664kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (11839) (tgid 11839), adj 1000,
   to free 34976kB on behalf of 'syz-fuzzer' (2044) because
   cache 260kB is below limit 6144kB for oom_score_adj 0
   Free memory is -14660kB above reserved
INFO: task syz-executor.2:17106 blocked for more than 140 seconds.
      Not tainted 4.9.141+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D28776 17106   2083 0x80000002
 ffff8801c94ddf00 0000000000000000 ffff8801d4b03c80 ffff8801d8410000
 ffff8801db721018 ffff88017b40f510 ffffffff828075c2 ffffffff83c27940
 0000000041b58ab3 ffffffff82e33920 00ffffff83c7a980 ffff8801db7218f0
Call Trace:
 [<ffffffff82808aef>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff828142d5>] schedule_timeout+0x735/0xe20 kernel/time/timer.c:1771
 [<ffffffff8280a63f>] do_wait_for_common kernel/sched/completion.c:75 [inline]
 [<ffffffff8280a63f>] __wait_for_common kernel/sched/completion.c:93 [inline]
 [<ffffffff8280a63f>] wait_for_common+0x3ef/0x5d0 kernel/sched/completion.c:101
 [<ffffffff8280a838>] wait_for_completion+0x18/0x20 kernel/sched/completion.c:122
 [<ffffffff81243b37>] __wait_rcu_gp+0x137/0x1b0 kernel/rcu/update.c:369
 [<ffffffff8124c21a>] synchronize_rcu.part.55+0xfa/0x110 kernel/rcu/tree_plugin.h:684
 [<ffffffff8124c257>] synchronize_rcu+0x27/0x90 kernel/rcu/tree_plugin.h:685
 [<ffffffff8156fb0e>] namespace_unlock+0xfe/0x120 fs/namespace.c:1440
 [<ffffffff81578c0b>] drop_collected_mounts+0x8b/0xa0 fs/namespace.c:1871
 [<ffffffff8157e877>] put_mnt_ns+0x47/0x60 fs/namespace.c:3320
 [<ffffffff81146ba4>] free_nsproxy+0x44/0x1d0 kernel/nsproxy.c:175
 [<ffffffff81146f98>] switch_task_namespaces+0x98/0xb0 kernel/nsproxy.c:228
 [<ffffffff81146fc7>] exit_task_namespaces+0x17/0x20 kernel/nsproxy.c:233
 [<ffffffff810e6c48>] do_exit+0x788/0x2a50 kernel/exit.c:832
 [<ffffffff810ed3a1>] do_group_exit+0x111/0x300 kernel/exit.c:937
 [<ffffffff8110eb61>] get_signal+0x4e1/0x1460 kernel/signal.c:2321
 [<ffffffff81052aa5>] do_signal+0x95/0x1b00 arch/x86/kernel/signal.c:807
 [<ffffffff81003e2e>] exit_to_usermode_loop+0x10e/0x150 arch/x86/entry/common.c:158
 [<ffffffff81005932>] prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 [<ffffffff81005932>] syscall_return_slowpath arch/x86/entry/common.c:263 [inline]
 [<ffffffff81005932>] do_syscall_64+0x3e2/0x550 arch/x86/entry/common.c:290
 [<ffffffff82817893>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131c0cc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131c0cc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813fe63f>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/1899:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff8156cc7c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/2027:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82815952>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d37362>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
2 locks held by syz-executor.4/3644:
 #0:  (&sb->s_type->i_mutex_key#8){+.+.+.}, at: [<ffffffff8229bd8b>] inode_lock include/linux/fs.h:766 [inline]
 #0:  (&sb->s_type->i_mutex_key#8){+.+.+.}, at: [<ffffffff8229bd8b>] __sock_release+0x8b/0x260 net/socket.c:604
 #1:  (sk_lock-AF_PACKET){+.+.+.}, at: [<ffffffff827d136d>] lock_sock include/net/sock.h:1404 [inline]
 #1:  (sk_lock-AF_PACKET){+.+.+.}, at: [<ffffffff827d136d>] packet_release+0x4ad/0xb70 net/packet/af_packet.c:3029

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.141+ #1
 ffff8801d9907d08 ffffffff81b42e79 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810983b0 ffff8801d9907d40
 ffffffff81b4df89 0000000000000001 0000000000000000 0000000000000002
Call Trace:
 [<ffffffff81b42e79>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b42e79>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81b4df89>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b4df1c>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff810984b4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131c65d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131c65d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131c65d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131c65d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff81142c3d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff82817a5c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 17231 Comm: syz-executor.3 Not tainted 4.9.141+ #1
task: ffff880198e017c0 task.stack: ffff8801c5228000
RIP: 0010:[<ffffffff81d6254b>] c [<ffffffff81d6254b>] io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:414
RSP: 0000:ffff8801c522eee0  EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: ffffffff81d624f1 RDI: ffffffff84b5bb58
RBP: ffff8801c522eef0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff84b5bb20
R13: 0000000000000020 R14: fffffbfff096b7ab R15: fffffbfff096b76d
FS:  00007f851da54700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000405fb0 CR3: 00000001d79a5000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff84b5bb20c 000000000000270dc ffff8801c522ef40c ffffffff81d64764c
 ffffffff81b6cdd8c ffffffff84b5bb68c ffffffff84b5bd5ac ffffffff84b5bb20c
 0000000000000039c ffffffff81d648b0c dffffc0000000000c 0000000000000039c
Call Trace:
 [<ffffffff81d64764>] serial_in drivers/tty/serial/8250/8250.h:111 [inline]
 [<ffffffff81d64764>] wait_for_xmitr+0x94/0x1e0 drivers/tty/serial/8250/8250_port.c:1997
 [<ffffffff81d648cf>] serial8250_console_putchar+0x1f/0x60 drivers/tty/serial/8250/8250_port.c:3103
 [<ffffffff81d4cce9>] uart_console_write+0x59/0xf0 drivers/tty/serial/serial_core.c:1866
 [<ffffffff81d6fae8>] serial8250_console_write+0x528/0x820 drivers/tty/serial/8250/8250_port.c:3169
 [<ffffffff81d5d4ff>] univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:594
 [<ffffffff8122387d>] call_console_drivers.isra.0.constprop.15+0x1ad/0x360 kernel/printk/printk.c:1594
 [<ffffffff812265af>] console_unlock+0x47f/0xb50 kernel/printk/printk.c:2454
 [<ffffffff812270c8>] vprintk_emit+0x448/0x790 kernel/printk/printk.c:1908
 [<ffffffff81227438>] vprintk+0x28/0x30 kernel/printk/printk.c:1918
 [<ffffffff8122745d>] vprintk_default+0x1d/0x30 kernel/printk/printk.c:1919
 [<ffffffff81402f9f>] vprintk_func kernel/printk/internal.h:36 [inline]
 [<ffffffff81402f9f>] printk+0xaf/0xd7 kernel/printk/printk.c:1980
 [<ffffffff8222d9e8>] lowmem_scan.cold.1+0x1f9/0x35b drivers/staging/android/lowmemorykiller.c:177
 [<ffffffff81449cc6>] do_shrink_slab mm/vmscan.c:398 [inline]
 [<ffffffff81449cc6>] shrink_slab.part.8+0x3c6/0xa00 mm/vmscan.c:501
 [<ffffffff814557fd>] shrink_slab mm/vmscan.c:465 [inline]
 [<ffffffff814557fd>] shrink_node+0x1ed/0x740 mm/vmscan.c:2602
 [<ffffffff814560c7>] shrink_zones mm/vmscan.c:2749 [inline]
 [<ffffffff814560c7>] do_try_to_free_pages mm/vmscan.c:2791 [inline]
 [<ffffffff814560c7>] try_to_free_pages+0x377/0xb80 mm/vmscan.c:3002
 [<ffffffff81428a01>] __perform_reclaim mm/page_alloc.c:3324 [inline]
 [<ffffffff81428a01>] __alloc_pages_direct_reclaim mm/page_alloc.c:3345 [inline]
 [<ffffffff81428a01>] __alloc_pages_slowpath mm/page_alloc.c:3697 [inline]
 [<ffffffff81428a01>] __alloc_pages_nodemask+0x981/0x1bd0 mm/page_alloc.c:3862
 [<ffffffff814c9e8b>] __alloc_pages include/linux/gfp.h:433 [inline]
 [<ffffffff814c9e8b>] __alloc_pages_node include/linux/gfp.h:446 [inline]
 [<ffffffff814c9e8b>] alloc_pages_node include/linux/gfp.h:460 [inline]
 [<ffffffff814c9e8b>] __vmalloc_area_node mm/vmalloc.c:1644 [inline]
 [<ffffffff814c9e8b>] __vmalloc_node_range+0x25b/0x600 mm/vmalloc.c:1702
 [<ffffffff814ca71b>] __vmalloc_node mm/vmalloc.c:1745 [inline]
 [<ffffffff814ca71b>] __vmalloc_node_flags mm/vmalloc.c:1759 [inline]
 [<ffffffff814ca71b>] vmalloc+0x5b/0x70 mm/vmalloc.c:1774
 [<ffffffff82450e91>] xt_alloc_entry_offsets+0x41/0x60 net/netfilter/x_tables.c:758
 [<ffffffff82783c95>] translate_table+0x215/0x1690 net/ipv6/netfilter/ip6_tables.c:733
 [<ffffffff827873ee>] do_replace net/ipv6/netfilter/ip6_tables.c:1186 [inline]
 [<ffffffff827873ee>] do_ip6t_set_ctl+0x2ce/0x470 net/ipv6/netfilter/ip6_tables.c:1712
 [<ffffffff823e290d>] nf_sockopt net/netfilter/nf_sockopt.c:105 [inline]
 [<ffffffff823e290d>] nf_setsockopt+0x6d/0xc0 net/netfilter/nf_sockopt.c:114
 [<ffffffff826f53f8>] ipv6_setsockopt+0xc8/0x130 net/ipv6/ipv6_sockglue.c:922
 [<ffffffff824deaa8>] tcp_setsockopt+0x88/0xe0 net/ipv4/tcp.c:2758
 [<ffffffff822a747a>] sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2706
 [<ffffffff822a4d76>] SYSC_setsockopt net/socket.c:1785 [inline]
 [<ffffffff822a4d76>] SyS_setsockopt+0x166/0x260 net/socket.c:1764
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82817893>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: c24 cc9 c00 c00 c00 c49 c8d c7c c24 c38 c48 cb8 c00 c00 c00 c00 c00 cfc cff cdf c48 c89 cfa c48 cc1 cea c03 cd3 ce3 c80 c3c c02 c00 c75 c17 c41 c03 c5c c24 c38 c89 cda cec c<5b> c0f cb6 cc0 c41 c5c c5d cc3 ce8 ca8 c0a c79 cff ceb cc2 ce8 c01 c0b c79 cff ceb c

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/08/19 06:14 https://android.googlesource.com/kernel/common android-4.9 8fe428403e30 b8ceabfc .config console log report ci-android-49-kasan-gce
2019/01/16 04:02 https://android.googlesource.com/kernel/common android-4.9 8fe428403e30 b47fa78d .config console log report ci-android-49-kasan-gce
2019/06/28 03:11 https://android.googlesource.com/kernel/common android-4.9 8fe428403e30 7509bf36 .config console log report ci-android-49-kasan-gce-386
* Struck through repros no longer work on HEAD.