RBP: 00007fed59a461d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffed0100c4f R14: 00007fed59a46300 R15: 0000000000022000 ====================================================== WARNING: possible circular locking dependency detected 5.10.79 #1 Not tainted ------------------------------------------------------ syz-executor.5/12400 is trying to acquire lock: ffffffff84d0a900 (console_owner){-.-.}-{0:0}, at: console_unlock+0x2e1/0xb30 kernel/printk/printk.c:2505 but task is already holding lock: ffff888017c21158 (&port->lock){-.-.}-{2:2}, 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){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x36/0x50 kernel/locking/spinlock.c:159 tty_port_tty_get+0x1f/0x100 drivers/tty/tty_port.c:288 tty_port_default_wakeup+0x11/0x40 drivers/tty/tty_port.c:47 serial8250_tx_chars+0x516/0xb40 drivers/tty/serial/8250/8250_port.c:1851 serial8250_handle_irq.part.0+0x3f1/0x4c0 drivers/tty/serial/8250/8250_port.c:1938 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1911 [inline] serial8250_default_handle_irq+0xb8/0x230 drivers/tty/serial/8250/8250_port.c:1954 serial8250_interrupt+0xf4/0x1a0 drivers/tty/serial/8250/8250_core.c:126 __handle_irq_event_percpu+0x2ef/0x820 kernel/irq/handle.c:156 handle_irq_event_percpu kernel/irq/handle.c:196 [inline] handle_irq_event+0x102/0x290 kernel/irq/handle.c:213 handle_edge_irq+0x249/0xd00 kernel/irq/chip.c:822 asm_call_irq_on_stack+0x12/0x20 __run_irq_on_irqstack arch/x86/include/asm/irq_stack.h:48 [inline] run_irq_on_irqstack_cond arch/x86/include/asm/irq_stack.h:101 [inline] handle_irq arch/x86/kernel/irq.c:230 [inline] __common_interrupt arch/x86/kernel/irq.c:249 [inline] common_interrupt+0xdd/0x190 arch/x86/kernel/irq.c:239 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:626 native_restore_fl arch/x86/include/asm/irqflags.h:41 [inline] arch_local_irq_restore arch/x86/include/asm/irqflags.h:84 [inline] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x25/0x40 kernel/locking/spinlock.c:191 spin_unlock_irqrestore include/linux/spinlock.h:409 [inline] uart_write+0x304/0x580 drivers/tty/serial/serial_core.c:615 do_output_char+0x5e4/0x860 drivers/tty/n_tty.c:442 process_output drivers/tty/n_tty.c:509 [inline] n_tty_write+0x487/0xf90 drivers/tty/n_tty.c:2361 do_tty_write drivers/tty/tty_io.c:1028 [inline] file_tty_write.constprop.0+0x4f8/0x8d0 drivers/tty/tty_io.c:1118 redirected_tty_write+0xa1/0xc0 drivers/tty/tty_io.c:1125 call_write_iter include/linux/fs.h:1903 [inline] do_iter_readv_writev+0x476/0x750 fs/read_write.c:740 do_iter_write+0x18d/0x670 fs/read_write.c:866 vfs_writev+0x1aa/0x5e0 fs/read_write.c:939 do_writev+0x139/0x300 fs/read_write.c:982 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&port_lock_key){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x36/0x50 kernel/locking/spinlock.c:159 serial8250_console_write+0x8dd/0xb20 drivers/tty/serial/8250/8250_port.c:3324 call_console_drivers kernel/printk/printk.c:1909 [inline] console_unlock+0x826/0xb30 kernel/printk/printk.c:2530 register_console kernel/printk/printk.c:2871 [inline] register_console+0x53d/0x800 kernel/printk/printk.c:2761 univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:690 console_init+0x361/0x4fa kernel/printk/printk.c:2981 start_kernel+0x2f2/0x49b init/main.c:984 secondary_startup_64_no_verify+0xc2/0xcb -> #0 (console_owner){-.-.}-{0:0}: check_prev_add kernel/locking/lockdep.c:2986 [inline] check_prevs_add kernel/locking/lockdep.c:3111 [inline] validate_chain kernel/locking/lockdep.c:3726 [inline] __lock_acquire+0x29e3/0x5b00 kernel/locking/lockdep.c:4952 lock_acquire kernel/locking/lockdep.c:5562 [inline] lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5527 console_lock_spinning_enable kernel/printk/printk.c:1761 [inline] console_unlock+0x360/0xb30 kernel/printk/printk.c:2527 vprintk_emit+0x1da/0x4d0 kernel/printk/printk.c:2052 vprintk_func+0x8b/0x140 kernel/printk/printk_safe.c:401 printk+0xba/0xed kernel/printk/printk.c:2100 fail_dump lib/fault-inject.c:45 [inline] should_fail+0x472/0x5a0 lib/fault-inject.c:146 should_failslab+0x5/0x10 mm/slab_common.c:1193 slab_pre_alloc_hook mm/slab.h:515 [inline] slab_alloc_node mm/slub.c:2821 [inline] slab_alloc mm/slub.c:2904 [inline] __kmalloc+0x72/0x3e0 mm/slub.c:3967 kmalloc include/linux/slab.h:557 [inline] tty_buffer_alloc+0x23f/0x2a0 drivers/tty/tty_buffer.c:175 __tty_buffer_request_room+0x156/0x2a0 drivers/tty/tty_buffer.c:273 tty_insert_flip_string_fixed_flag+0x91/0x250 drivers/tty/tty_buffer.c:318 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x126/0x1f0 drivers/tty/pty.c:122 n_tty_write+0xa44/0xf90 drivers/tty/n_tty.c:2372 do_tty_write drivers/tty/tty_io.c:1028 [inline] file_tty_write.constprop.0+0x4f8/0x8d0 drivers/tty/tty_io.c:1118 call_write_iter include/linux/fs.h:1903 [inline] new_sync_write+0x42c/0x660 fs/read_write.c:518 vfs_write+0x743/0xa20 fs/read_write.c:605 ksys_write+0x12d/0x250 fs/read_write.c:658 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: console_owner --> &port_lock_key --> &port->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&port->lock); lock(&port_lock_key); lock(&port->lock); lock(console_owner); *** DEADLOCK *** 6 locks held by syz-executor.5/12400: #0: ffff8880155eb098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:266 #1: ffff8880155eb130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:952 [inline] #1: ffff8880155eb130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:975 [inline] #1: ffff8880155eb130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write.constprop.0+0x29d/0x8d0 drivers/tty/tty_io.c:1118 #2: ffff8880155eb2e8 (&tty->termios_rwsem){++++}-{3:3}, at: n_tty_write+0x1bf/0xf90 drivers/tty/n_tty.c:2332 #3: ffffc9000073b378 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_write+0xa0b/0xf90 drivers/tty/n_tty.c:2371 #4: ffff888017c21158 (&port->lock){-.-.}-{2:2}, at: pty_write+0xf4/0x1f0 drivers/tty/pty.c:120 #5: ffffffff84deac80 (console_lock){+.+.}-{0:0}, at: vprintk_func+0x8b/0x140 kernel/printk/printk_safe.c:401 stack backtrace: CPU: 0 PID: 12400 Comm: syz-executor.5 Not tainted 5.10.79 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2121 check_prev_add kernel/locking/lockdep.c:2986 [inline] check_prevs_add kernel/locking/lockdep.c:3111 [inline] validate_chain kernel/locking/lockdep.c:3726 [inline] __lock_acquire+0x29e3/0x5b00 kernel/locking/lockdep.c:4952 lock_acquire kernel/locking/lockdep.c:5562 [inline] lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5527 console_lock_spinning_enable kernel/printk/printk.c:1761 [inline] console_unlock+0x360/0xb30 kernel/printk/printk.c:2527 vprintk_emit+0x1da/0x4d0 kernel/printk/printk.c:2052 vprintk_func+0x8b/0x140 kernel/printk/printk_safe.c:401 printk+0xba/0xed kernel/printk/printk.c:2100 fail_dump lib/fault-inject.c:45 [inline] should_fail+0x472/0x5a0 lib/fault-inject.c:146 should_failslab+0x5/0x10 mm/slab_common.c:1193 slab_pre_alloc_hook mm/slab.h:515 [inline] slab_alloc_node mm/slub.c:2821 [inline] slab_alloc mm/slub.c:2904 [inline] __kmalloc+0x72/0x3e0 mm/slub.c:3967 kmalloc include/linux/slab.h:557 [inline] tty_buffer_alloc+0x23f/0x2a0 drivers/tty/tty_buffer.c:175 __tty_buffer_request_room+0x156/0x2a0 drivers/tty/tty_buffer.c:273 tty_insert_flip_string_fixed_flag+0x91/0x250 drivers/tty/tty_buffer.c:318 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x126/0x1f0 drivers/tty/pty.c:122 n_tty_write+0xa44/0xf90 drivers/tty/n_tty.c:2372 do_tty_write drivers/tty/tty_io.c:1028 [inline] file_tty_write.constprop.0+0x4f8/0x8d0 drivers/tty/tty_io.c:1118 call_write_iter include/linux/fs.h:1903 [inline] new_sync_write+0x42c/0x660 fs/read_write.c:518 vfs_write+0x743/0xa20 fs/read_write.c:605 ksys_write+0x12d/0x250 fs/read_write.c:658 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fed5c4d0b19 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:00007fed59a46188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fed5c5e3f60 RCX: 00007fed5c4d0b19 RDX: 0000000000000020 RSI: 0000000020000640 RDI: 0000000000000004 RBP: 00007fed59a461d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffed0100c4f R14: 00007fed59a46300 R15: 0000000000022000 audit: type=1326 audit(1637642459.021:101): auid=0 uid=0 gid=0 ses=4 subj=system_u:system_r:kernel_t:s0 pid=12386 comm="syz-executor.0" exe="/syz-executor.0" sig=0 arch=c000003e syscall=165 compat=0 ip=0x7f3961b4404a code=0x7ffc0000 audit: type=1326 audit(1637642459.061:102): auid=0 uid=0 gid=0 ses=4 subj=system_u:system_r:kernel_t:s0 pid=12386 comm="syz-executor.0" exe="/syz-executor.0" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7f3961b42b19 code=0x7ffc0000 audit: type=1326 audit(1637642459.062:103): auid=0 uid=0 gid=0 ses=4 subj=system_u:system_r:kernel_t:s0 pid=12386 comm="syz-executor.0" exe="/syz-executor.0" sig=0 arch=c000003e syscall=78 compat=0 ip=0x7f3961b42b19 code=0x7ffc0000 audit: type=1326 audit(1637642459.062:104): auid=0 uid=0 gid=0 ses=4 subj=system_u:system_r:kernel_t:s0 pid=12386 comm="syz-executor.0" exe="/syz-executor.0" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7f3961b42b19 code=0x7ffc0000 audit: type=1326 audit(1637642459.265:105): auid=0 uid=0 gid=0 ses=4 subj=system_u:system_r:kernel_t:s0 pid=12386 comm="syz-executor.0" exe="/syz-executor.0" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7f3961b42b19 code=0x7ffc0000 audit: type=1326 audit(1637642459.270:106): auid=0 uid=0 gid=0 ses=4 subj=system_u:system_r:kernel_t:s0 pid=12386 comm="syz-executor.0" exe="/syz-executor.0" sig=0 arch=c000003e syscall=257 compat=0 ip=0x7f3961b42b19 code=0x7ffc0000 netlink: 'syz-executor.4': attribute type 2 has an invalid length. netlink: 'syz-executor.4': attribute type 2 has an invalid length. netlink: 'syz-executor.4': attribute type 2 has an invalid length.