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INFO: task hung in ptmx_open

Status: auto-closed as invalid on 2019/03/21 04:01
First crash: 2032d, last: 2032d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in ptmx_open serial 4 802d 876d 0/26 closed as invalid on 2022/02/08 09:40

Sample crash report:
audit: type=1400 audit(1537588346.221:37049): avc:  denied  { net_admin } for  pid=2086 comm="syz-executor2" capability=12  scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1
audit: type=1400 audit(1537588346.281:37050): avc:  denied  { net_admin } for  pid=2086 comm="syz-executor2" capability=12  scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1
INFO: task syz-executor0:12137 blocked for more than 140 seconds.
      Not tainted 4.9.128+ #93
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D29208 12137   2085 0x00000004
 ffff8801cb52af80 ffff8801d1371600 ffff8801d1371600 ffff8801cff70000
 ffff8801db721018 ffff88019ea7f7b8 ffffffff8277ee02 0000000000000000
 ffff8801cb52b830 ffffed00396a5705 00ff8801cb52af80 ffff8801db7218f0
Call Trace:
 [<ffffffff8278032f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff82780cb3>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff82782936>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff82782936>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff81cec497>] ptmx_open+0xf7/0x310 drivers/tty/pty.c:753
 [<ffffffff814f839d>] chrdev_open+0x22d/0x4c0 fs/char_dev.c:392
 [<ffffffff814e284f>] do_dentry_open+0x3ef/0xc90 fs/open.c:766
 [<ffffffff814e617c>] vfs_open+0x11c/0x210 fs/open.c:879
 [<ffffffff8151cde2>] do_last fs/namei.c:3410 [inline]
 [<ffffffff8151cde2>] path_openat+0x542/0x2790 fs/namei.c:3534
 [<ffffffff81521eb7>] do_filp_open+0x197/0x270 fs/namei.c:3568
 [<ffffffff814e6b8d>] do_sys_open+0x30d/0x5c0 fs/open.c:1072
 [<ffffffff814e6eb0>] SYSC_openat fs/open.c:1099 [inline]
 [<ffffffff814e6eb0>] SyS_openat+0x30/0x40 fs/open.c:1093
 [<ffffffff8100554f>] do_syscall_64+0x19f/0x480 arch/x86/entry/common.c:282
 [<ffffffff8278df13>] 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: [<ffffffff8130a0ac>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8130a0ac>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.?..}, at: [<ffffffff813e71ec>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/1897:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff8154c6fc>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/2024:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff8278bfd2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff81cdee72>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor3/6659:
 #0:  (&sig->cred_guard_mutex){+.+.+.}, at: [<ffffffff81501563>] prepare_bprm_creds+0x53/0x110 fs/exec.c:1369
1 lock held by syz-executor0/12137:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cec497>] ptmx_open+0xf7/0x310 drivers/tty/pty.c:753
1 lock held by syz-executor0/12148:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cec497>] ptmx_open+0xf7/0x310 drivers/tty/pty.c:753
1 lock held by init/12142:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cd36a6>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cd36a6>] tty_open+0x476/0xdf0 drivers/tty/tty_io.c:2125
1 lock held by init/12143:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cd36a6>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cd36a6>] tty_open+0x476/0xdf0 drivers/tty/tty_io.c:2125
1 lock held by init/12144:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cd36a6>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cd36a6>] tty_open+0x476/0xdf0 drivers/tty/tty_io.c:2125
1 lock held by init/12145:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cd36a6>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cd36a6>] tty_open+0x476/0xdf0 drivers/tty/tty_io.c:2125
1 lock held by init/12146:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cd36a6>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cd36a6>] tty_open+0x476/0xdf0 drivers/tty/tty_io.c:2125
1 lock held by init/12147:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cd36a6>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff81cd36a6>] tty_open+0x476/0xdf0 drivers/tty/tty_io.c:2125

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

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.128+ #93
 ffff8801d9907d08 ffffffff81af2469 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810967d0 ffff8801d9907d40
 ffffffff81afd1c9 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81af2469>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81af2469>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81afd1c9>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81afd15c>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff810968d4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8130a63d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8130a63d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8130a63d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8130a63d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff8113e00d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff8278e0dc>] 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: 12107 Comm: syz-executor3 Not tainted 4.9.128+ #93
task: ffff8801d20a8000 task.stack: ffff8801cfcd8000
RIP: 0010:[<ffffffff8130c725>] c [<ffffffff8130c725>] __seccomp_filter+0x1a5/0xc80 kernel/seccomp.c:653
RSP: 0018:ffff8801cfcdfcb8  EFLAGS: 00000246
RAX: 0000000000000003 RBX: ffff8801cfce0000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8130c813 RDI: ffffffff84010440
RBP: ffff8801cfcdfdc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 000000007ff00000
R13: 00000000ffffffff R14: dffffc0000000000 R15: ffff8801cfcdfe48
FS:  00007f634d230700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4daed7a000 CR3: 00000001c778b000 CR4: 00000000001606b0
Stack:
 0000000000000003c ffff8801db6210a0c ffff8801d20a8080c ffff8801d20a8080c
 0000000000000000c 0000000000000000c 000000ca00000000c 1ffff10039f9bf9fc
 0000000041b58ab3c ffffffff82c2dc17c ffffffff8130c580c ffff8801db6210a0c
Call Trace:
 [<ffffffff8130ebc6>] __secure_computing+0xa6/0x290 kernel/seccomp.c:692
 [<ffffffff81004940>] syscall_trace_enter+0x550/0xd20 arch/x86/entry/common.c:117
 [<ffffffff8100566c>] do_syscall_64+0x2bc/0x480 arch/x86/entry/common.c:273
 [<ffffffff8278df13>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: c05 c00 c41 c0f cb7 cdd c0f c84 c5d c03 c00 c00 c76 c68 c41 c81 cfc c00 c00 cf0 c7f c0f c84 ccd c01 c00 c00 c41 c81 cfc c00 c00 cff c7f c0f c85 ca9 c0a c00 c00 c45 c31 ced c<e8> c16 cd3 cff cff c44 c89 ce8 c48 cba c00 c00 c00 c00 c00 cfc cff cdf c48 c03 c95 c

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/09/22 03:55 https://android.googlesource.com/kernel/common android-4.9 1c57ba4f543b 37079712 .config console log report ci-android-49-kasan-gce
* Struck through repros no longer work on HEAD.