RBP: 00007f07d222d1d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffd13f3139f R14: 00007f07d222d300 R15: 0000000000022000
======================================================
WARNING: possible circular locking dependency detected
5.10.158 #1 Not tainted
------------------------------------------------------
syz-executor.2/6793 is trying to acquire lock:
ffffffff84f0c2a0 (console_owner){-.-.}-{0:0}, at: console_unlock+0x2e1/0xb40 kernel/printk/printk.c:2507

but task is already holding lock:
ffff88801b028958 (&port->lock){-.-.}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x2b/0x160 drivers/tty/tty_buffer.c:575

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+0x36/0x60 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+0x51f/0xb00 drivers/tty/serial/8250/8250_port.c:1831
       __start_tx drivers/tty/serial/8250/8250_port.c:1550 [inline]
       serial8250_start_tx+0x695/0xa60 drivers/tty/serial/8250/8250_port.c:1655
       __uart_start.isra.0+0x17c/0x1c0 drivers/tty/serial/serial_core.c:132
       uart_write+0x2f2/0x580 drivers/tty/serial/serial_core.c:613
       do_output_char+0x5e8/0x870 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:2395
       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+0xa5/0xd0 drivers/tty/tty_io.c:1125
       call_write_iter include/linux/fs.h:1904 [inline]
       do_iter_readv_writev+0x476/0x750 fs/read_write.c:740
       do_iter_write+0x191/0x670 fs/read_write.c:866
       vfs_writev+0x1ae/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+0x61/0xc6

-> #1 (&port_lock_key){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x36/0x60 kernel/locking/spinlock.c:159
       serial8250_console_write+0x9f5/0xc60 drivers/tty/serial/8250/8250_port.c:3322
       call_console_drivers kernel/printk/printk.c:1911 [inline]
       console_unlock+0x82a/0xb40 kernel/printk/printk.c:2532
       register_console kernel/printk/printk.c:2873 [inline]
       register_console+0x53d/0x800 kernel/printk/printk.c:2763
       univ8250_console_init+0x3a/0x4a drivers/tty/serial/8250/8250_core.c:700
       console_init+0x361/0x4fa kernel/printk/printk.c:2983
       start_kernel+0x2e1/0x48e init/main.c:982
       secondary_startup_64_no_verify+0xc2/0xcb

-> #0 (console_owner){-.-.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:2988 [inline]
       check_prevs_add kernel/locking/lockdep.c:3113 [inline]
       validate_chain kernel/locking/lockdep.c:3728 [inline]
       __lock_acquire+0x29e7/0x5b00 kernel/locking/lockdep.c:4954
       lock_acquire kernel/locking/lockdep.c:5565 [inline]
       lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5530
       console_lock_spinning_enable kernel/printk/printk.c:1763 [inline]
       console_unlock+0x360/0xb40 kernel/printk/printk.c:2529
       vprintk_emit+0x1de/0x4d0 kernel/printk/printk.c:2054
       vprintk_func+0x8b/0x140 kernel/printk/printk_safe.c:401
       printk+0xba/0xf1 kernel/printk/printk.c:2102
       fail_dump lib/fault-inject.c:45 [inline]
       should_fail+0x47a/0x5a0 lib/fault-inject.c:146
       should_failslab+0x5/0x20 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+0x72/0x3f0 mm/slub.c:3967
       kmalloc include/linux/slab.h:557 [inline]
       tty_buffer_alloc+0x243/0x2b0 drivers/tty/tty_buffer.c:175
       __tty_buffer_request_room+0x156/0x2a0 drivers/tty/tty_buffer.c:274
       tty_insert_flip_string_fixed_flag+0x91/0x250 drivers/tty/tty_buffer.c:319
       tty_insert_flip_string include/linux/tty_flip.h:36 [inline]
       tty_insert_flip_string_and_push_buffer+0x3e/0x160 drivers/tty/tty_buffer.c:576
       pty_write+0xe6/0x110 drivers/tty/pty.c:118
       tty_send_xchar+0x29b/0x3c0 drivers/tty/tty_io.c:1175
       n_tty_ioctl_helper+0x191/0x3a0 drivers/tty/tty_ioctl.c:870
       n_tty_ioctl+0x56/0x370 drivers/tty/n_tty.c:2516
       tty_ioctl+0x912/0x1840 drivers/tty/tty_io.c:2751
       vfs_ioctl fs/ioctl.c:48 [inline]
       __do_sys_ioctl fs/ioctl.c:753 [inline]
       __se_sys_ioctl fs/ioctl.c:739 [inline]
       __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739
       do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x61/0xc6

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 ***

5 locks held by syz-executor.2/6793:
 #0: ffff88800f003098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x90 drivers/tty/tty_ldisc.c:266
 #1: ffff88800f003130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:952 [inline]
 #1: ffff88800f003130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_send_xchar+0x1e2/0x3c0 drivers/tty/tty_io.c:1169
 #2: ffff88800f0032e8 (&o_tty->termios_rwsem/1){++++}-{3:3}, at: tty_send_xchar+0x22f/0x3c0 drivers/tty/tty_io.c:1172
 #3: ffff88801b028958 (&port->lock){-.-.}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x2b/0x160 drivers/tty/tty_buffer.c:575
 #4: ffffffff84fec620 (console_lock){+.+.}-{0:0}, at: vprintk_func+0x8b/0x140 kernel/printk/printk_safe.c:401

stack backtrace:
CPU: 0 PID: 6793 Comm: syz-executor.2 Not tainted 5.10.158 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x107/0x167 lib/dump_stack.c:118
 check_noncircular+0x263/0x2e0 kernel/locking/lockdep.c:2123
 check_prev_add kernel/locking/lockdep.c:2988 [inline]
 check_prevs_add kernel/locking/lockdep.c:3113 [inline]
 validate_chain kernel/locking/lockdep.c:3728 [inline]
 __lock_acquire+0x29e7/0x5b00 kernel/locking/lockdep.c:4954
 lock_acquire kernel/locking/lockdep.c:5565 [inline]
 lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5530
 console_lock_spinning_enable kernel/printk/printk.c:1763 [inline]
 console_unlock+0x360/0xb40 kernel/printk/printk.c:2529
 vprintk_emit+0x1de/0x4d0 kernel/printk/printk.c:2054
 vprintk_func+0x8b/0x140 kernel/printk/printk_safe.c:401
 printk+0xba/0xf1 kernel/printk/printk.c:2102
 fail_dump lib/fault-inject.c:45 [inline]
 should_fail+0x47a/0x5a0 lib/fault-inject.c:146
 should_failslab+0x5/0x20 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+0x72/0x3f0 mm/slub.c:3967
 kmalloc include/linux/slab.h:557 [inline]
 tty_buffer_alloc+0x243/0x2b0 drivers/tty/tty_buffer.c:175
 __tty_buffer_request_room+0x156/0x2a0 drivers/tty/tty_buffer.c:274
 tty_insert_flip_string_fixed_flag+0x91/0x250 drivers/tty/tty_buffer.c:319
 tty_insert_flip_string include/linux/tty_flip.h:36 [inline]
 tty_insert_flip_string_and_push_buffer+0x3e/0x160 drivers/tty/tty_buffer.c:576
 pty_write+0xe6/0x110 drivers/tty/pty.c:118
 tty_send_xchar+0x29b/0x3c0 drivers/tty/tty_io.c:1175
 n_tty_ioctl_helper+0x191/0x3a0 drivers/tty/tty_ioctl.c:870
 n_tty_ioctl+0x56/0x370 drivers/tty/n_tty.c:2516
 tty_ioctl+0x912/0x1840 drivers/tty/tty_io.c:2751
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xc6
RIP: 0033:0x7f07d4cb7b19
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:00007f07d222d188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f07d4dcaf60 RCX: 00007f07d4cb7b19
RDX: 0000000000000003 RSI: 000000000000540a RDI: 0000000000000005
RBP: 00007f07d222d1d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffd13f3139f R14: 00007f07d222d300 R15: 0000000000022000
EXT4-fs (loop7): mounting ext2 file system using the ext4 subsystem
EXT4-fs (loop7): bad geometry: block count 256 exceeds size of device (2 blocks)
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
CPU: 1 PID: 6811 Comm: syz-executor.2 Not tainted 5.10.158 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x107/0x167 lib/dump_stack.c:118
 fail_dump lib/fault-inject.c:52 [inline]
 should_fail.cold+0x5/0xa lib/fault-inject.c:146
 should_failslab+0x5/0x20 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]
 kmem_cache_alloc+0x5b/0x360 mm/slub.c:2909
 mem_pool_alloc mm/kmemleak.c:423 [inline]
 create_object.isra.0+0x3a/0xa20 mm/kmemleak.c:578
 kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline]
 slab_post_alloc_hook mm/slab.h:534 [inline]
 slab_alloc_node mm/slub.c:2896 [inline]
 slab_alloc mm/slub.c:2904 [inline]
 __kmalloc+0x16e/0x3f0 mm/slub.c:3967
 kmalloc include/linux/slab.h:557 [inline]
 tty_buffer_alloc+0x243/0x2b0 drivers/tty/tty_buffer.c:175
 __tty_buffer_request_room+0x156/0x2a0 drivers/tty/tty_buffer.c:274
 tty_insert_flip_string_fixed_flag+0x91/0x250 drivers/tty/tty_buffer.c:319
 tty_insert_flip_string include/linux/tty_flip.h:36 [inline]
 tty_insert_flip_string_and_push_buffer+0x3e/0x160 drivers/tty/tty_buffer.c:576
 pty_write+0xe6/0x110 drivers/tty/pty.c:118
 tty_send_xchar+0x29b/0x3c0 drivers/tty/tty_io.c:1175
 n_tty_ioctl_helper+0x191/0x3a0 drivers/tty/tty_ioctl.c:870
 n_tty_ioctl+0x56/0x370 drivers/tty/n_tty.c:2516
 tty_ioctl+0x912/0x1840 drivers/tty/tty_io.c:2751
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xc6
RIP: 0033:0x7f07d4cb7b19
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:00007f07d222d188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f07d4dcaf60 RCX: 00007f07d4cb7b19
RDX: 0000000000000003 RSI: 000000000000540a RDI: 0000000000000005
RBP: 00007f07d222d1d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffd13f3139f R14: 00007f07d222d300 R15: 0000000000022000
EXT4-fs (loop7): mounting ext2 file system using the ext4 subsystem
EXT4-fs (loop7): bad geometry: block count 256 exceeds size of device (2 blocks)