INFO: task syz-executor4:11527 blocked for more than 140 seconds. Not tainted 4.19.0-rc8+ #64 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D24896 11527 5622 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x86c/0x1ed0 kernel/sched/core.c:3473 schedule+0xfe/0x460 kernel/sched/core.c:3517 __rwsem_down_write_failed_common+0xbb9/0x1670 kernel/locking/rwsem-xadd.c:566 rwsem_down_write_failed+0xe/0x10 kernel/locking/rwsem-xadd.c:595 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write_nested+0xa9/0x130 kernel/locking/rwsem.c:194 inode_lock_nested include/linux/fs.h:773 [inline] lock_rename+0x236/0x290 fs/namei.c:2862 do_renameat2+0x696/0x1180 fs/namei.c:4577 __do_sys_rename fs/namei.c:4673 [inline] __se_sys_rename fs/namei.c:4671 [inline] __x64_sys_rename+0x5e/0x80 fs/namei.c:4671 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457569 Code: 83 c4 18 c3 e8 d8 64 00 00 48 8b 04 24 48 8b 4c 24 08 48 89 01 e8 d7 2d fc ff e8 22 7a fc ff b8 02 00 00 00 48 8d 0d 2a 60 09 <01> 87 01 8b 05 22 60 09 01 83 f8 01 0f 85 8a 00 00 00 b8 01 00 00 RSP: 002b:00007fd5e1029c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000457569 RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000020000600 RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd5e102a6d4 R13: 00000000004c3281 R14: 00000000004d4e78 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/984: #0: 000000001c21d917 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4435 2 locks held by rsyslogd/5365: #0: 00000000803f0610 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 #1: 00000000d0f37f53 (&rq->lock){-.-.}, at: syslog_print kernel/printk/printk.c:1305 [inline] #1: 00000000d0f37f53 (&rq->lock){-.-.}, at: do_syslog+0xc45/0x1690 kernel/printk/printk.c:1465 2 locks held by getty/5487: #0: 00000000bf99db27 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000062cbc210 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5488: #0: 00000000e5d1651f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000007cc1d896 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5489: #0: 00000000d15b7aaa (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000009dd69111 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5490: #0: 000000008b1919cd (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000070f71513 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5491: #0: 000000003b8a5327 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000c762d7d4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5492: #0: 000000008bdae76a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000005cb2ff03 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5493: #0: 0000000019ca3a29 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000d48121ca (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 1 lock held by syz-executor1/10222: #0: 000000003eb92743 (&sig->cred_guard_mutex){+.+.}, at: prepare_bprm_creds+0x53/0x120 fs/exec.c:1404 2 locks held by syz-executor4/11505: #0: 00000000b76e12bd (sb_writers#17){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 00000000b76e12bd (sb_writers#17){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 00000000cfb35876 (&sb->s_type->i_mutex_key#23/1){+.+.}, at: inode_lock_nested include/linux/fs.h:773 [inline] #1: 00000000cfb35876 (&sb->s_type->i_mutex_key#23/1){+.+.}, at: lock_rename+0x236/0x290 fs/namei.c:2862 2 locks held by syz-executor4/11527: #0: 00000000b76e12bd (sb_writers#17){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 00000000b76e12bd (sb_writers#17){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 00000000cfb35876 (&sb->s_type->i_mutex_key#23/1){+.+.}, at: inode_lock_nested include/linux/fs.h:773 [inline] #1: 00000000cfb35876 (&sb->s_type->i_mutex_key#23/1){+.+.}, at: lock_rename+0x236/0x290 fs/namei.c:2862 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 984 Comm: khungtaskd Not tainted 4.19.0-rc8+ #64 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+0x1c4/0x2b4 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.3+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x1ed 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:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0xb3e/0x1050 kernel/hung_task.c:265 kthread+0x35a/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:57