INFO: task syz-executor5:28331 blocked for more than 140 seconds. Not tainted 4.19.0-rc6+ #39 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D25400 28331 5550 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+0xa5/0x130 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:738 [inline] chown_common+0x3a9/0x730 fs/open.c:629 do_fchownat+0x16e/0x250 fs/open.c:662 __do_sys_chown fs/open.c:682 [inline] __se_sys_chown fs/open.c:680 [inline] __x64_sys_chown+0x7b/0xc0 fs/open.c:680 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457579 Code: Bad RIP value. RSP: 002b:00007fa6e2f8dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000005c RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457579 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000140 RBP: 000000000072c0e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa6e2f8e6d4 R13: 00000000004c2539 R14: 00000000004cc3a0 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/983: #0: 0000000074313c78 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4435 1 lock held by rsyslogd/5273: #0: 00000000c595de8d (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/5364: #0: 000000006ac9d7c2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000d502df55 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5365: #0: 000000004f811286 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000f636bed4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5366: #0: 0000000087b8f3a4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000020927f68 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5367: #0: 00000000e3d009ab (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000002759f201 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5368: #0: 00000000e4495ce3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000e563d859 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5369: #0: 00000000db8b1cc6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000003a5fd7a4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5370: #0: 00000000f327cef3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000088cc2baf (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by syz-executor5/28285: #0: 000000002aa6edad (sb_writers#13){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 000000002aa6edad (sb_writers#13){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 0000000073c1c85a (&sb->s_type->i_mutex_key#19){++++}, at: inode_lock include/linux/fs.h:738 [inline] #1: 0000000073c1c85a (&sb->s_type->i_mutex_key#19){++++}, at: chown_common+0x3a9/0x730 fs/open.c:629 2 locks held by syz-executor5/28331: #0: 000000002aa6edad (sb_writers#13){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 000000002aa6edad (sb_writers#13){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 0000000073c1c85a (&sb->s_type->i_mutex_key#19){++++}, at: inode_lock include/linux/fs.h:738 [inline] #1: 0000000073c1c85a (&sb->s_type->i_mutex_key#19){++++}, at: chown_common+0x3a9/0x730 fs/open.c:629 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 983 Comm: khungtaskd Not tainted 4.19.0-rc6+ #39 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