syzbot


INFO: task hung in tty_set_termios

Status: auto-closed as invalid on 2019/02/22 14:59
First crash: 2068d, last: 2068d
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in tty_set_termios (2) 3 624d 734d 0/1 auto-obsoleted due to no activity on 2022/10/05 22:41
upstream INFO: task hung in tty_set_termios serial 1 2155d 2154d 8/26 fixed on 2018/07/09 18:05
linux-4.19 INFO: task hung in tty_set_termios 1 1191d 1191d 0/1 auto-closed as invalid on 2021/03/18 18:50
upstream INFO: task hung in tty_set_termios (2) serial 2 879d 917d 0/26 auto-closed as invalid on 2021/12/25 14:45

Sample crash report:
sd 0:0:1:0: [sg0] tag#932 CDB[10]: 0c 95 28 08 be c3 ca d6 48 ab 84 8b b2 c7 ec 63
sd 0:0:1:0: [sg0] tag#932 CDB[20]: f4
INFO: task syz-executor2:10323 blocked for more than 120 seconds.
      Not tainted 4.9.109-g7cecc75 #2
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor2   D28984 10323   3845 0x00000004
 ffff8801cf234800 0000000000000000 ffff88016f245f80 ffff8801d56c3000
 ffff8801db221c18 ffff8801d95e7568 ffffffff839e8a3d ffffffff812355f7
 0000000000000000 ffff8801cf2350c0 0000000600000007 ffff8801db2224e8
Call Trace:
 [<ffffffff839ea03f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839f5678>] __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:526 [inline]
 [<ffffffff839f5678>] rwsem_down_write_failed+0x598/0x990 kernel/locking/rwsem-xadd.c:555
 [<ffffffff81ee8107>] call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:105
 [<ffffffff839f344c>] __down_write arch/x86/include/asm/rwsem.h:125 [inline]
 [<ffffffff839f344c>] down_write+0x5c/0xa0 kernel/locking/rwsem.c:54
 [<ffffffff821281e7>] tty_set_termios+0xe7/0x8a0 drivers/tty/tty_ioctl.c:549
 [<ffffffff8212978f>] set_termios+0x38f/0x620 drivers/tty/tty_ioctl.c:635
 [<ffffffff8212a17b>] tty_mode_ioctl+0x75b/0x980 drivers/tty/tty_ioctl.c:1002
 [<ffffffff8212a444>] n_tty_ioctl_helper+0x44/0x370 drivers/tty/tty_ioctl.c:1161
 [<ffffffff8211d586>] n_tty_ioctl+0x46/0x2c0 drivers/tty/n_tty.c:2443
 [<ffffffff82116934>] tty_ioctl+0x5a4/0x2270 drivers/tty/tty_io.c:3009
 [<ffffffff815b2b9c>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815b2b9c>] file_ioctl fs/ioctl.c:493 [inline]
 [<ffffffff815b2b9c>] do_vfs_ioctl+0x1ac/0x11a0 fs/ioctl.c:677
 [<ffffffff815b3c1f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815b3c1f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9913>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/519:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136662c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136662c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81425cb7>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3772:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f7ae2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211fce2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133
2 locks held by syz-executor2/10323:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f7ae2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&o_tty->termios_rwsem/1){++++..}, at: [<ffffffff821281e7>] tty_set_termios+0xe7/0x8a0 drivers/tty/tty_ioctl.c:549

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.109-g7cecc75 #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d844fd08 ffffffff81eb3e29 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9580 ffff8801d844fd40
 ffffffff81ebf127 0000000000000000 0000000000000000 0000000000000002
Call Trace:
 [<ffffffff81eb3e29>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb3e29>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebf127>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebf0ba>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b9684>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81366bc4>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366bc4>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366bc4>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366bc4>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d04d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f9adc>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 22 Comm: kworker/u4:1 Not tainted 4.9.109-g7cecc75 #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound flush_to_ldiscc
task: ffff8801d9aeb000 task.stack: ffff8801d9bd0000
RIP: 0010:[<ffffffff8135e960>] c [<ffffffff8135e960>] check_kcov_mode kernel/kcov.c:66 [inline]
RIP: 0010:[<ffffffff8135e960>] c [<ffffffff8135e960>] __sanitizer_cov_trace_pc+0x20/0x50 kernel/kcov.c:100
RSP: 0018:ffff8801d9bd79c8  EFLAGS: 00000246
RAX: ffff8801d9aeb000 RBX: ffffc90012807000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8211bb8f RDI: ffffc900128089e2
RBP: ffff8801d9bd79c8 R08: ffff8801d9aeb9b0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00000006e8e20783
R13: 00000000000fcc7a R14: dffffc0000000000 R15: 00000006e8e20783
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c446fb1000 CR3: 00000001c575c000 CR4: 00000000001606f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Stack:
 ffff8801d9bd7a40c ffffffff8211bb8fc 0000000000000246c ffff8801d9bd79f8c
 ffffc90012809278c ffffed0039928b15c ffff8801cc9458acc ffffc90012807020c
 0000000000000000c ffff8801cc945500c ffffc90012809300c ffffc90012807000c
Call Trace:
 [<ffffffff8211bb8f>] echo_buf drivers/tty/n_tty.c:146 [inline]
 [<ffffffff8211bb8f>] __process_echoes+0x5cf/0x780 drivers/tty/n_tty.c:734
 [<ffffffff821255c4>] flush_echoes drivers/tty/n_tty.c:801 [inline]
 [<ffffffff821255c4>] __receive_buf drivers/tty/n_tty.c:1617 [inline]
 [<ffffffff821255c4>] n_tty_receive_buf_common+0xd34/0x2300 drivers/tty/n_tty.c:1711
 [<ffffffff82126bc3>] n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1746
 [<ffffffff8212c6bf>] tty_ldisc_receive_buf+0xaf/0x190 drivers/tty/tty_buffer.c:455
 [<ffffffff8212d6c3>] receive_buf drivers/tty/tty_buffer.c:474 [inline]
 [<ffffffff8212d6c3>] flush_to_ldisc+0x253/0x370 drivers/tty/tty_buffer.c:533
 [<ffffffff8118d121>] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092
 [<ffffffff8118df16>] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226
 [<ffffffff8119d04d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f9adc>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Code: c0f c1f c84 c00 c00 c00 c00 c00 c0f c1f c00 c55 c48 c89 ce5 c65 c48 c8b c04 c25 cc0 c7d c01 c00 c65 c8b c15 cfc c93 ccb c7e c81 ce2 c00 c01 c1f c00 c48 c8b c75 c08 c75 c2b c<8b> c90 c80 c12 c00 c00 c83 cfa c02 c75 c20 c48 c8b c88 c88 c12 c00 c00 c8b c80 c84 c

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/06/25 01:32 https://android.googlesource.com/kernel/common android-4.9 7cecc756ceae 2064fc5c .config console log report ci-android-49-kasan-gce-root
* Struck through repros no longer work on HEAD.