RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000005 RBP: 00007f96d669b1d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffc2d84e70f R14: 00007f96d669b300 R15: 0000000000022000 ====================================================== WARNING: possible circular locking dependency detected 4.19.206-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.5/8274 is trying to acquire lock: 00000000f905ef4e (console_owner){-.-.}, at: console_trylock_spinning kernel/printk/printk.c:1697 [inline] 00000000f905ef4e (console_owner){-.-.}, at: vprintk_emit+0x3fe/0x740 kernel/printk/printk.c:1964 but task is already holding lock: 00000000a7c324e3 (&(&port->lock)->rlock){-.-.}, at: pty_write+0xf4/0x1f0 drivers/tty/pty.c:120 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&(&port->lock)->rlock){-.-.}: tty_port_tty_get+0x1d/0x80 drivers/tty/tty_port.c:289 tty_port_default_wakeup+0x11/0x40 drivers/tty/tty_port.c:47 serial8250_tx_chars+0x490/0xaf0 drivers/tty/serial/8250/8250_port.c:1812 serial8250_handle_irq.part.0+0x31f/0x3d0 drivers/tty/serial/8250/8250_port.c:1899 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1872 [inline] serial8250_default_handle_irq+0xae/0x220 drivers/tty/serial/8250/8250_port.c:1915 serial8250_interrupt+0x101/0x240 drivers/tty/serial/8250/8250_core.c:125 __handle_irq_event_percpu+0x27e/0x8e0 kernel/irq/handle.c:149 handle_irq_event_percpu kernel/irq/handle.c:189 [inline] handle_irq_event+0x102/0x290 kernel/irq/handle.c:206 handle_edge_irq+0x260/0xcf0 kernel/irq/chip.c:800 generic_handle_irq_desc include/linux/irqdesc.h:155 [inline] handle_irq+0x35/0x50 arch/x86/kernel/irq_64.c:87 do_IRQ+0x93/0x1c0 arch/x86/kernel/irq.c:246 ret_from_intr+0x0/0x1e native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0x49/0x310 arch/x86/kernel/process.c:557 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x2ec/0x4b0 kernel/sched/idle.c:263 cpu_startup_entry+0xc5/0xe0 kernel/sched/idle.c:369 start_secondary+0x435/0x5c0 arch/x86/kernel/smpboot.c:271 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #1 (&port_lock_key){-.-.}: serial8250_console_write+0x90e/0xb70 drivers/tty/serial/8250/8250_port.c:3289 call_console_drivers kernel/printk/printk.c:1764 [inline] console_unlock+0xbb6/0x1110 kernel/printk/printk.c:2460 vprintk_emit+0x2d1/0x740 kernel/printk/printk.c:1965 vprintk_func+0x79/0x180 kernel/printk/printk_safe.c:405 printk+0xba/0xed kernel/printk/printk.c:2040 register_console+0x87f/0xc90 kernel/printk/printk.c:2776 univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:684 console_init+0x4cb/0x718 kernel/printk/printk.c:2862 start_kernel+0x686/0x911 init/main.c:659 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #0 (console_owner){-.-.}: console_trylock_spinning kernel/printk/printk.c:1718 [inline] vprintk_emit+0x43b/0x740 kernel/printk/printk.c:1964 vprintk_func+0x79/0x180 kernel/printk/printk_safe.c:405 printk+0xba/0xed kernel/printk/printk.c:2040 fail_dump lib/fault-inject.c:44 [inline] should_fail+0x66b/0x7b0 lib/fault-inject.c:149 __should_failslab+0x115/0x180 mm/failslab.c:32 should_failslab+0x5/0x10 mm/slab_common.c:1590 slab_pre_alloc_hook mm/slab.h:424 [inline] slab_alloc mm/slab.c:3383 [inline] __do_kmalloc mm/slab.c:3725 [inline] __kmalloc+0x6d/0x3c0 mm/slab.c:3736 kmalloc include/linux/slab.h:520 [inline] tty_buffer_alloc+0x23f/0x2a0 drivers/tty/tty_buffer.c:170 __tty_buffer_request_room+0x156/0x2a0 drivers/tty/tty_buffer.c:268 tty_insert_flip_string_fixed_flag+0x93/0x250 drivers/tty/tty_buffer.c:313 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x126/0x1f0 drivers/tty/pty.c:122 n_hdlc_send_frames+0x278/0x470 drivers/tty/n_hdlc.c:403 n_hdlc_tty_wakeup+0xa0/0xc0 drivers/tty/n_hdlc.c:479 tty_ldisc_hangup+0x410/0x700 drivers/tty/tty_ldisc.c:731 __tty_hangup.part.0+0x359/0x780 drivers/tty/tty_io.c:623 __tty_hangup drivers/tty/tty_io.c:573 [inline] tty_vhangup+0x1d/0x30 drivers/tty/tty_io.c:696 pty_close+0x3a1/0x4f0 drivers/tty/pty.c:79 tty_release+0x45e/0x1210 drivers/tty/tty_io.c:1678 __fput+0x2ce/0x890 fs/file_table.c:278 task_work_run+0x148/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: console_owner --> &port_lock_key --> &(&port->lock)->rlock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&port->lock)->rlock); lock(&port_lock_key); lock(&(&port->lock)->rlock); lock(console_owner); *** DEADLOCK *** 4 locks held by syz-executor.5/8274: #0: 0000000061ef3e33 (&tty->legacy_mutex){+.+.}, at: tty_lock+0x6a/0xa0 drivers/tty/tty_mutex.c:19 #1: 0000000046976263 (&tty->legacy_mutex/1){+.+.}, at: tty_lock+0x6a/0xa0 drivers/tty/tty_mutex.c:19 #2: 00000000aef6826f (&tty->ldisc_sem){++++}, at: tty_ldisc_ref drivers/tty/tty_ldisc.c:293 [inline] #2: 00000000aef6826f (&tty->ldisc_sem){++++}, at: tty_ldisc_hangup+0x2c/0x700 drivers/tty/tty_ldisc.c:724 #3: 00000000a7c324e3 (&(&port->lock)->rlock){-.-.}, at: pty_write+0xf4/0x1f0 drivers/tty/pty.c:120 stack backtrace: CPU: 0 PID: 8274 Comm: syz-executor.5 Not tainted 4.19.206-syzkaller #0 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+0x1fc/0x2ef lib/dump_stack.c:118 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222 check_prev_add kernel/locking/lockdep.c:1866 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2420 [inline] __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 console_trylock_spinning kernel/printk/printk.c:1718 [inline] vprintk_emit+0x43b/0x740 kernel/printk/printk.c:1964 vprintk_func+0x79/0x180 kernel/printk/printk_safe.c:405 printk+0xba/0xed kernel/printk/printk.c:2040 fail_dump lib/fault-inject.c:44 [inline] should_fail+0x66b/0x7b0 lib/fault-inject.c:149 __should_failslab+0x115/0x180 mm/failslab.c:32 should_failslab+0x5/0x10 mm/slab_common.c:1590 slab_pre_alloc_hook mm/slab.h:424 [inline] slab_alloc mm/slab.c:3383 [inline] __do_kmalloc mm/slab.c:3725 [inline] __kmalloc+0x6d/0x3c0 mm/slab.c:3736 kmalloc include/linux/slab.h:520 [inline] tty_buffer_alloc+0x23f/0x2a0 drivers/tty/tty_buffer.c:170 __tty_buffer_request_room+0x156/0x2a0 drivers/tty/tty_buffer.c:268 tty_insert_flip_string_fixed_flag+0x93/0x250 drivers/tty/tty_buffer.c:313 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x126/0x1f0 drivers/tty/pty.c:122 n_hdlc_send_frames+0x278/0x470 drivers/tty/n_hdlc.c:403 n_hdlc_tty_wakeup+0xa0/0xc0 drivers/tty/n_hdlc.c:479 tty_ldisc_hangup+0x410/0x700 drivers/tty/tty_ldisc.c:731 __tty_hangup.part.0+0x359/0x780 drivers/tty/tty_io.c:623 __tty_hangup drivers/tty/tty_io.c:573 [inline] tty_vhangup+0x1d/0x30 drivers/tty/tty_io.c:696 pty_close+0x3a1/0x4f0 drivers/tty/pty.c:79 tty_release+0x45e/0x1210 drivers/tty/tty_io.c:1678 __fput+0x2ce/0x890 fs/file_table.c:278 task_work_run+0x148/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4665f9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f96d669b188 EFLAGS: 00000246 ORIG_RAX: 0000000000000124 RAX: 0000000000000003 RBX: 000000000056c038 RCX: 00000000004665f9 RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000005 RBP: 00007f96d669b1d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffc2d84e70f R14: 00007f96d669b300 R15: 0000000000022000 x_tables: ip_tables: CT.2 target: invalid size 72 (kernel) != (user) 5 ptrace attach of "/root/syz-executor.4"[8416] was attempted by "/root/syz-executor.4"[8421] audit: type=1804 audit(1630917571.726:195): pid=8438 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.4" name="/root/syzkaller-testdir818411456/syzkaller.qQdZqK/1287/cgroup.controllers" dev="sda1" ino=14092 res=1 netlink: 32 bytes leftover after parsing attributes in process `syz-executor.4'. ieee802154 phy0 wpan0: encryption failed: -22 netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'. ieee802154 phy0 wpan0: encryption failed: -22 ieee802154 phy0 wpan0: encryption failed: -22 ieee802154 phy0 wpan0: encryption failed: -22 ieee802154 phy0 wpan0: encryption failed: -22 ieee802154 phy0 wpan0: encryption failed: -22 netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'. ieee802154 phy0 wpan0: encryption failed: -22 ieee802154 phy0 wpan0: encryption failed: -22 ieee802154 phy0 wpan0: encryption failed: -22