INFO: task syz-executor3:30891 blocked for more than 140 seconds. Not tainted 4.19.0-rc6+ #165 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D21816 30891 1 0x20020004 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+0xa5/0x130 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:738 [inline] vfs_unlink+0xd1/0x510 fs/namei.c:3991 do_unlinkat+0x6cc/0xa30 fs/namei.c:4063 __do_sys_unlink fs/namei.c:4110 [inline] __se_sys_unlink fs/namei.c:4108 [inline] __ia32_sys_unlink+0x41/0x50 fs/namei.c:4108 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f1aca9 Code: Bad RIP value. RSP: 002b:000000000845ed1c EFLAGS: 00000212 ORIG_RAX: 000000000000000a RAX: ffffffffffffffda RBX: 000000000845edac RCX: 000000005bb14217 RDX: 0000000009e2f198 RSI: 0000000000000000 RDI: 00000000080d2058 RBP: 000000000845edac R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/982: #0: 00000000a635c25e (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4435 2 locks held by getty/5298: #0: 00000000872baf35 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000e4506aac (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5299: #0: 000000008827be4c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000d80f10e2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5300: #0: 00000000df1b37d1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000b613c6bc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5301: #0: 00000000381cfbaa (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000d8a8b342 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5302: #0: 000000003e31a6c7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000d9836e9a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5303: #0: 00000000210b74c7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000065de6695 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5304: #0: 00000000a177f882 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000077900e63 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 3 locks held by syz-executor3/30891: #0: 000000007442c5de (sb_writers#5){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 000000007442c5de (sb_writers#5){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 0000000041a54ae1 (&type->i_mutex_dir_key#4/1){+.+.}, at: inode_lock_nested include/linux/fs.h:773 [inline] #1: 0000000041a54ae1 (&type->i_mutex_dir_key#4/1){+.+.}, at: do_unlinkat+0x3d8/0xa30 fs/namei.c:4049 #2: 00000000e5b4e341 (&sb->s_type->i_mutex_key#12){+.+.}, at: inode_lock include/linux/fs.h:738 [inline] #2: 00000000e5b4e341 (&sb->s_type->i_mutex_key#12){+.+.}, at: vfs_unlink+0xd1/0x510 fs/namei.c:3991 3 locks held by syz-executor3/31215: #0: 00000000f8c193ce (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 #1: 000000007442c5de (sb_writers#5){.+.+}, at: file_start_write include/linux/fs.h:2759 [inline] #1: 000000007442c5de (sb_writers#5){.+.+}, at: vfs_write+0x42a/0x560 fs/read_write.c:548 #2: 00000000e5b4e341 (&sb->s_type->i_mutex_key#12){+.+.}, at: inode_lock include/linux/fs.h:738 [inline] #2: 00000000e5b4e341 (&sb->s_type->i_mutex_key#12){+.+.}, at: generic_file_write_iter+0xed/0x870 mm/filemap.c:3289 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 982 Comm: khungtaskd Not tainted 4.19.0-rc6+ #165 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