syzbot


INFO: task hung in n_tty_read

Status: auto-closed as invalid on 2020/01/25 18:14
Reported-by: syzbot+415e8787a9e5ff0a4e69@syzkaller.appspotmail.com
First crash: 1884d, last: 1884d
Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 INFO: task hung in n_tty_read 6 1732d 1773d 0/1 auto-closed as invalid on 2020/06/25 03:18
upstream INFO: task hung in n_tty_read (2) usb serial input C error 1 1328d 1324d 0/28 auto-obsoleted due to no activity on 2023/04/25 23:58
upstream INFO: task hung in n_tty_read serial 3 1749d 1803d 0/28 auto-closed as invalid on 2020/05/09 10:39
linux-4.14 INFO: task hung in n_tty_read (2) 1 1307d 1307d 0/1 auto-closed as invalid on 2021/08/24 04:16
linux-4.19 INFO: task hung in n_tty_read (2) 1 788d 788d 0/1 auto-obsoleted due to no activity on 2023/01/25 23:32
linux-4.19 INFO: task hung in n_tty_read 2 1789d 1800d 0/1 auto-closed as invalid on 2020/04/29 17:03

Sample crash report:
audit: type=1400 audit(1569608009.430:211): avc:  denied  { create } for  pid=11834 comm="syz-executor.3" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
INFO: task syz-executor.0:7591 blocked for more than 140 seconds.
      Not tainted 4.4.174+ #17
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D
audit: type=1400 audit(1569608009.760:212): avc:  denied  { write } for  pid=11834 comm="syz-executor.3" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
 ffff8800a39375f0 28976  7591   7566 0x20020000
 ffff8800a39375f0 ffff880100000001 ffff880000000000 ffffffff83a7f5d0
 ffff8801d46588c8 1ffff10014726e00 ffff8801db61f180 ffff8801db61f1a8
 ffff8801db61e898 ffff8800b43617c0 ffff8801d4658000 ffffed0014726001
Call Trace:
 [<ffffffff82709b79>] schedule+0x99/0x1d0 kernel/sched/core.c:3355
 [<ffffffff82715c4b>] schedule_timeout+0x47b/0x7c0 kernel/time/timer.c:1515
 [<ffffffff8270b455>] do_wait_for_common kernel/sched/completion.c:75 [inline]
 [<ffffffff8270b455>] __wait_for_common kernel/sched/completion.c:93 [inline]
 [<ffffffff8270b455>] wait_for_common+0x2b5/0x530 kernel/sched/completion.c:101
 [<ffffffff8270b6e8>] wait_for_completion+0x18/0x20 kernel/sched/completion.c:122
 [<ffffffff8111e8af>] flush_work+0x39f/0x6c0 kernel/workqueue.c:2774
 [<ffffffff81ca1536>] tty_buffer_flush_work+0x16/0x20 drivers/tty/tty_buffer.c:604
 [<ffffffff81c97ada>] n_tty_read+0x8fa/0x1e60 drivers/tty/n_tty.c:2256
 [<ffffffff81c850c6>] tty_read+0x166/0x260 drivers/tty/tty_io.c:1080
 [<ffffffff81496556>] __vfs_read+0x116/0x3c0 fs/read_write.c:434
 [<ffffffff81498264>] vfs_read+0x134/0x360 fs/read_write.c:456
 [<ffffffff8149aa8c>] SYSC_read fs/read_write.c:571 [inline]
 [<ffffffff8149aa8c>] SyS_read+0xdc/0x1c0 fs/read_write.c:564
 [<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 [<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397
 [<ffffffff8271a350>] sysenter_flags_fixed+0xd/0x1a
2 locks held by syz-executor.0/7591:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff81c9d34b>] tty_ldisc_ref_wait+0x2b/0xc0 drivers/tty/tty_ldisc.c:263
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff81c973de>] n_tty_read+0x1fe/0x1e60 drivers/tty/n_tty.c:2204
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 20 Comm: khungtaskd Not tainted 4.4.174+ #17
task: ffff8801da6c5f00 task.stack: ffff8800001c8000
RIP: 0010:[<ffffffff8109b617>]  [<ffffffff8109b617>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:62 [inline]
RIP: 0010:[<ffffffff8109b617>]  [<ffffffff8109b617>] flat_send_IPI_mask+0xf7/0x1b0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800001cfc88  EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fc300
RBP: ffff8800001cfcb8 R08: 0000000000000018 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000003000000 R14: ffffffff82e5f2e0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7f1e9bb330 CR3: 00000000a8602000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000001 ffffffff82e5f2e0 ffffffff831a6ac0 fffffbfff0634c34
 000000000001b6c0 0000000000000008 ffff8800001cfcd8 ffffffff81092bee
 0000000000000008 ffffffff82924260 ffff8800001cfd30 ffffffff81ab8252
Call Trace:
 [<ffffffff81092bee>] nmi_raise_cpu_backtrace+0x5e/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81ab8252>] nmi_trigger_all_cpu_backtrace.cold+0xa1/0xae lib/nmi_backtrace.c:85
 [<ffffffff81092ca4>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff813b4762>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff813b4762>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff813b4762>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff813b4762>] watchdog.cold+0xd3/0xee kernel/hung_task.c:238
 [<ffffffff811342c3>] kthread+0x273/0x310 kernel/kthread.c:211
 [<ffffffff82718fc5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
Code: 00 c3 5f ff 80 e6 10 75 e1 41 c1 e5 18 44 89 2c 25 10 c3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 c3 5f ff <41> f7 c4 00 02 00 00 75 1e 4c 89 e7 57 9d 0f 1f 44 00 00 e8 f1 
NMI backtrace for cpu 1
CPU: 1 PID: 11844 Comm: syz-executor.3 Not tainted 4.4.174+ #17
task: ffff8801d7d497c0 task.stack: ffff8800b73e8000
RIP: 0010:[<ffffffff81cc252b>]  [<ffffffff81cc252b>] io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:399
RSP: 0018:ffff8800b73ef048  EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: ffffffff81cc24d1 RDI: ffffffff8496e518
RBP: ffff8800b73ef058 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: ffffffff83fdf24f R12: ffffffff8496e4e0
R13: 0000000000000020 R14: fffffbfff092dce3 R15: fffffbfff092dca5
FS:  0000000000000000(0000) GS:ffff8801db700000(0063) knlGS:00000000f54a6b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000020c05000 CR3: 00000001d5322000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8496e4e0 0000000000002707 ffff8800b73ef0a8 ffffffff81cc461f
 ffffed0016e7de2b ffffffff8496e528 ffffffff8496e71a ffffffff83fdf205
 ffffffff8496e4e0 000000000000003a dffffc0000000000 000000000000003a
Call Trace:
 [<ffffffff81cc461f>] serial_in drivers/tty/serial/8250/8250.h:97 [inline]
 [<ffffffff81cc461f>] wait_for_xmitr+0x8f/0x1e0 drivers/tty/serial/8250/8250_port.c:1717
 [<ffffffff81cc4790>] serial8250_console_putchar+0x20/0x60 drivers/tty/serial/8250/8250_port.c:2806
 [<ffffffff81caf7c6>] uart_console_write+0x56/0xe0 drivers/tty/serial/serial_core.c:1789
 [<ffffffff81cce12b>] serial8250_console_write+0x2fb/0x870 drivers/tty/serial/8250/8250_port.c:2872
 [<ffffffff81cbd84f>] univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:594
 [<ffffffff8121c8ff>] call_console_drivers.constprop.0+0x1ef/0x3f0 kernel/printk/printk.c:1468
 [<ffffffff8121fe02>] console_unlock kernel/printk/printk.c:2335 [inline]
 [<ffffffff8121fe02>] console_unlock+0x602/0xa10 kernel/printk/printk.c:2242
 [<ffffffff812205c2>] vprintk_emit+0x3b2/0x820 kernel/printk/printk.c:1837
 [<ffffffff81220a58>] vprintk+0x28/0x30 kernel/printk/printk.c:1848
 [<ffffffff813afd6f>] printk+0xc2/0xf5 kernel/printk/printk.c:1927
 [<ffffffff813b4486>] audit_printk_skb.cold+0x3e/0x4d kernel/audit.c:398
 [<ffffffff812df538>] audit_log_end+0x3b8/0x610 kernel/audit.c:1987
 [<ffffffff819aee74>] common_lsm_audit+0x554/0x19c0 security/lsm_audit.c:435
 [<ffffffff819551bf>] slow_avc_audit+0x17f/0x210 security/selinux/avc.c:773
 [<ffffffff81956690>] avc_audit security/selinux/include/avc.h:140 [inline]
 [<ffffffff81956690>] avc_has_perm+0x300/0x3a0 security/selinux/avc.c:1148
 [<ffffffff8195fd1d>] sock_has_perm+0x29d/0x400 security/selinux/hooks.c:4066
 [<ffffffff8196006f>] selinux_socket_sendmsg+0x3f/0x50 security/selinux/hooks.c:4313
 [<ffffffff81951363>] security_socket_sendmsg+0x83/0xc0 security/security.c:1238
 [<ffffffff821d8317>] sock_sendmsg+0x47/0x110 net/socket.c:645
 [<ffffffff821da269>] ___sys_sendmsg+0x769/0x890 net/socket.c:1975
 [<ffffffff821dd0c5>] __sys_sendm

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/09/27 18:13 https://android.googlesource.com/kernel/common android-4.4 62872f952d6b d8074e0b .config console log report ci-android-44-kasan-gce-386
* Struck through repros no longer work on HEAD.