INFO: task syz-executor4:8614 blocked for more than 140 seconds. Not tainted 4.19.0-rc5+ #251 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D23816 8614 5348 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: 0033:0x457679 Code: Bad RIP value. RSP: 002b:00007f6485f98c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 RAX: ffffffffffffffda RBX: 00007f6485f996d4 RCX: 0000000000457679 RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000020000040 RBP: 000000000072c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d5008 R14: 00000000004c3396 R15: 0000000000000002 Showing all locks held in the system: 1 lock held by khungtaskd/983: #0: 00000000fa022c65 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4435 1 lock held by rsyslogd/5207: 2 locks held by getty/5298: #0: 000000002b8c9b89 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000008b094cb3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5299: #0: 000000007c446c7a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000007319e417 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5300: #0: 00000000b2c96644 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000004e13194b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5301: #0: 000000006937c2f7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000074bf1194 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5302: #0: 0000000007efae25 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000002c9862e1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5303: #0: 000000002e51ec33 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000009c714594 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5304: #0: 0000000086664d71 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000602faba1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by syz-executor2/7939: #0: 00000000055d9f24 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000008ce9c739 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 4 locks held by syz-executor4/8574: #0: 00000000025b9ded (sb_writers#16){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 00000000025b9ded (sb_writers#16){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 00000000dd91ba7c (&sb->s_type->i_mutex_key#20/1){+.+.}, at: inode_lock_nested include/linux/fs.h:773 [inline] #1: 00000000dd91ba7c (&sb->s_type->i_mutex_key#20/1){+.+.}, at: lock_rename+0x236/0x290 fs/namei.c:2862 #2: 0000000053e53364 (&sb->s_type->i_mutex_key#20/4){+.+.}, at: inode_lock_nested include/linux/fs.h:773 [inline] #2: 0000000053e53364 (&sb->s_type->i_mutex_key#20/4){+.+.}, at: lock_two_nondirectories+0xdd/0x120 fs/inode.c:1009 #3: 00000000fbbda574 (&v9ses->rename_sem){++++}, at: v9fs_vfs_rename+0x330/0xd30 fs/9p/vfs_inode.c:1009 2 locks held by syz-executor4/8614: #0: 00000000025b9ded (sb_writers#16){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 00000000025b9ded (sb_writers#16){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 00000000dd91ba7c (&sb->s_type->i_mutex_key#20/1){+.+.}, at: inode_lock_nested include/linux/fs.h:773 [inline] #1: 00000000dd91ba7c (&sb->s_type->i_mutex_key#20/1){+.+.}, at: lock_rename+0x236/0x290 fs/namei.c:2862 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 983 Comm: khungtaskd Not tainted 4.19.0-rc5+ #251 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 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:57