kernel msg: ebtables bug: please report to author: Hook order must be followed INFO: task syz-executor2:6963 blocked for more than 140 seconds. Not tainted 4.19.0-rc5+ #30 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D24504 6963 5358 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] filename_create+0x1b2/0x5b0 fs/namei.c:3635 user_path_create fs/namei.c:3693 [inline] do_symlinkat+0xfe/0x2d0 fs/namei.c:4147 __do_sys_symlinkat fs/namei.c:4168 [inline] __se_sys_symlinkat fs/namei.c:4165 [inline] __x64_sys_symlinkat+0x73/0xb0 fs/namei.c:4165 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:00007f3765ff6c78 EFLAGS: 00000246 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457579 RDX: 00000000200005c0 RSI: 0000000000000005 RDI: 0000000020000540 RBP: 000000000072c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3765ff76d4 R13: 00000000004c47c4 R14: 00000000004d7940 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/984: #0: 00000000eb9d8e7f (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4435 1 lock held by rsyslogd/5221: #0: 00000000d25c2827 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/5311: #0: 0000000085e1c0ef (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000005310d54a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5312: #0: 000000002ec73e9b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000b7c840be (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5313: #0: 00000000c5619016 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000e9db05ef (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5314: #0: 000000005e234d40 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000fa9f30e9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5315: #0: 00000000c01cb165 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000cf9f94ba (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5316: #0: 00000000702cdb6f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000000a8b86f9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5317: #0: 00000000894b52a1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000f46f07ad (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by syz-executor2/6892: #0: 0000000020664104 (sb_writers#12){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 0000000020664104 (sb_writers#12){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 00000000ca5e8ace (&sb->s_type->i_mutex_key#16/1){+.+.}, at: inode_lock_nested include/linux/fs.h:773 [inline] #1: 00000000ca5e8ace (&sb->s_type->i_mutex_key#16/1){+.+.}, at: filename_create+0x1b2/0x5b0 fs/namei.c:3635 2 locks held by syz-executor2/6963: #0: 0000000020664104 (sb_writers#12){.+.+}, at: sb_start_write include/linux/fs.h:1566 [inline] #0: 0000000020664104 (sb_writers#12){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:360 #1: 00000000ca5e8ace (&sb->s_type->i_mutex_key#16/1){+.+.}, at: inode_lock_nested include/linux/fs.h:773 [inline] #1: 00000000ca5e8ace (&sb->s_type->i_mutex_key#16/1){+.+.}, at: filename_create+0x1b2/0x5b0 fs/namei.c:3635 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 984 Comm: khungtaskd Not tainted 4.19.0-rc5+ #30 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