FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 ------------[ cut here ]------------ CPU: 0 PID: 17980 Comm: syz-executor0 Not tainted 4.20.0+ #1 downgrading a read lock WARNING: CPU: 1 PID: 17982 at kernel/locking/lockdep.c:3553 __lock_downgrade kernel/locking/lockdep.c:3553 [inline] WARNING: CPU: 1 PID: 17982 at kernel/locking/lockdep.c:3553 lock_downgrade+0x4d2/0x910 kernel/locking/lockdep.c:3816 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Kernel panic - not syncing: panic_on_warn set ... Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold+0xa/0x15 lib/fault-inject.c:149 __should_failslab+0x121/0x190 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1603 slab_pre_alloc_hook mm/slab.h:423 [inline] slab_alloc mm/slab.c:3365 [inline] __do_kmalloc mm/slab.c:3707 [inline] __kmalloc+0x71/0x740 mm/slab.c:3718 kmalloc include/linux/slab.h:550 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:175 [inline] __tty_buffer_request_room+0x2bf/0x7e0 drivers/tty/tty_buffer.c:273 tty_insert_flip_string_fixed_flag+0x93/0x1f0 drivers/tty/tty_buffer.c:318 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x133/0x200 drivers/tty/pty.c:122 process_output_block drivers/tty/n_tty.c:593 [inline] n_tty_write+0x497/0x1220 drivers/tty/n_tty.c:2331 do_tty_write drivers/tty/tty_io.c:959 [inline] tty_write+0x45b/0x7a0 drivers/tty/tty_io.c:1043 __vfs_write+0x116/0xb40 fs/read_write.c:485 vfs_write+0x20c/0x580 fs/read_write.c:549 ksys_write+0x105/0x260 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f314b444c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f314b444c90 RCX: 0000000000457ec9 RDX: 0000000000001006 RSI: 0000000020001640 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f314b4456d4 R13: 00000000004c6ec1 R14: 00000000004dc3b8 R15: 0000000000000007 CPU: 1 PID: 17982 Comm: blkid Not tainted 4.20.0+ #1 ====================================================== WARNING: possible circular locking dependency detected 4.20.0+ #1 Not tainted ------------------------------------------------------ syz-executor0/17980 is trying to acquire lock: 000000008b7fecfc (console_owner){-.-.}, at: log_next kernel/printk/printk.c:492 [inline] 000000008b7fecfc (console_owner){-.-.}, at: console_unlock+0x4d3/0x11e0 kernel/printk/printk.c:2395 but task is already holding lock: 000000000fdcb9f3 (&(&port->lock)->rlock){-.-.}, at: pty_write+0xff/0x200 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){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 tty_port_tty_get+0x22/0x80 drivers/tty/tty_port.c:287 tty_port_default_wakeup+0x16/0x40 drivers/tty/tty_port.c:47 tty_port_tty_wakeup+0x5d/0x70 drivers/tty/tty_port.c:387 uart_write_wakeup+0x46/0x70 drivers/tty/serial/serial_core.c:103 serial8250_tx_chars+0x4a4/0xb20 drivers/tty/serial/8250/8250_port.c:1806 serial8250_handle_irq.part.0+0x1be/0x2e0 drivers/tty/serial/8250/8250_port.c:1879 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1865 [inline] serial8250_default_handle_irq+0xc5/0x150 drivers/tty/serial/8250/8250_port.c:1895 serial8250_interrupt+0xfb/0x1a0 drivers/tty/serial/8250/8250_core.c:125 __handle_irq_event_percpu+0x1c6/0xb10 kernel/irq/handle.c:149 handle_irq_event_percpu+0xa0/0x1d0 kernel/irq/handle.c:189 handle_irq_event+0xa7/0x134 kernel/irq/handle.c:206 handle_edge_irq+0x232/0x8a0 kernel/irq/chip.c:791 generic_handle_irq_desc include/linux/irqdesc.h:154 [inline] handle_irq+0x252/0x3d8 arch/x86/kernel/irq_64.c:78 do_IRQ+0x99/0x1d0 arch/x86/kernel/irq.c:246 ret_from_intr+0x0/0x1e native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:57 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:555 default_idle_call+0x36/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x386/0x5d0 kernel/sched/idle.c:262 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:353 start_secondary+0x435/0x620 arch/x86/kernel/smpboot.c:271 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #1 (&port_lock_key){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 serial8250_console_write+0x253/0xab0 drivers/tty/serial/8250/8250_port.c:3245 univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:586 call_console_drivers kernel/printk/printk.c:1737 [inline] console_unlock+0xcff/0x11e0 kernel/printk/printk.c:2408 vprintk_emit+0x370/0x960 kernel/printk/printk.c:1931 vprintk_default+0x28/0x30 kernel/printk/printk.c:1958 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:1991 register_console+0x74d/0xb50 kernel/printk/printk.c:2723 univ8250_console_init+0x3e/0x4b drivers/tty/serial/8250/8250_core.c:681 console_init+0x6b7/0x9fe kernel/printk/printk.c:2809 start_kernel+0x5df/0x8bd init/main.c:668 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:451 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #0 (console_owner){-.-.}: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841 console_lock_spinning_enable kernel/printk/printk.c:1600 [inline] console_unlock+0x53d/0x11e0 kernel/printk/printk.c:2405 vprintk_emit+0x370/0x960 kernel/printk/printk.c:1931 vprintk_default+0x28/0x30 kernel/printk/printk.c:1958 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:1991 fail_dump lib/fault-inject.c:44 [inline] should_fail+0xa59/0xd22 lib/fault-inject.c:149 __should_failslab+0x121/0x190 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1603 slab_pre_alloc_hook mm/slab.h:423 [inline] slab_alloc mm/slab.c:3365 [inline] __do_kmalloc mm/slab.c:3707 [inline] __kmalloc+0x71/0x740 mm/slab.c:3718 kmalloc include/linux/slab.h:550 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:175 [inline] __tty_buffer_request_room+0x2bf/0x7e0 drivers/tty/tty_buffer.c:273 tty_insert_flip_string_fixed_flag+0x93/0x1f0 drivers/tty/tty_buffer.c:318 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x133/0x200 drivers/tty/pty.c:122 process_output_block drivers/tty/n_tty.c:593 [inline] n_tty_write+0x497/0x1220 drivers/tty/n_tty.c:2331 do_tty_write drivers/tty/tty_io.c:959 [inline] tty_write+0x45b/0x7a0 drivers/tty/tty_io.c:1043 __vfs_write+0x116/0xb40 fs/read_write.c:485 vfs_write+0x20c/0x580 fs/read_write.c:549 ksys_write+0x105/0x260 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 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 *** 6 locks held by syz-executor0/17980: #0: 00000000492308e7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000474e78aa (&tty->atomic_write_lock){+.+.}, at: tty_write_lock+0x23/0x90 drivers/tty/tty_io.c:885 #2: 00000000d80c3330 (&o_tty->termios_rwsem/1){++++}, at: n_tty_write+0x246/0x1220 drivers/tty/n_tty.c:2314 #3: 00000000283ba96f (&ldata->output_lock){+.+.}, at: process_output_block drivers/tty/n_tty.c:548 [inline] #3: 00000000283ba96f (&ldata->output_lock){+.+.}, at: n_tty_write+0x5c9/0x1220 drivers/tty/n_tty.c:2331 #4: 000000000fdcb9f3 (&(&port->lock)->rlock){-.-.}, at: pty_write+0xff/0x200 drivers/tty/pty.c:120 #5: 00000000737e2cb7 (console_lock){+.+.}, at: console_trylock_spinning kernel/printk/printk.c:1662 [inline] #5: 00000000737e2cb7 (console_lock){+.+.}, at: vprintk_emit+0x351/0x960 kernel/printk/printk.c:1930 stack backtrace: CPU: 0 PID: 17980 Comm: syz-executor0 Not tainted 4.20.0+ #1 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+0x1db/0x2d0 lib/dump_stack.c:113 print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1224 check_prev_add kernel/locking/lockdep.c:1866 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2350 [inline] __lock_acquire+0x3014/0x4a30 kernel/locking/lockdep.c:3338 lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841 console_lock_spinning_enable kernel/printk/printk.c:1600 [inline] console_unlock+0x53d/0x11e0 kernel/printk/printk.c:2405 vprintk_emit+0x370/0x960 kernel/printk/printk.c:1931 vprintk_default+0x28/0x30 kernel/printk/printk.c:1958 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:1991 fail_dump lib/fault-inject.c:44 [inline] should_fail+0xa59/0xd22 lib/fault-inject.c:149 __should_failslab+0x121/0x190 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1603 slab_pre_alloc_hook mm/slab.h:423 [inline] slab_alloc mm/slab.c:3365 [inline] __do_kmalloc mm/slab.c:3707 [inline] __kmalloc+0x71/0x740 mm/slab.c:3718 kmalloc include/linux/slab.h:550 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:175 [inline] __tty_buffer_request_room+0x2bf/0x7e0 drivers/tty/tty_buffer.c:273 tty_insert_flip_string_fixed_flag+0x93/0x1f0 drivers/tty/tty_buffer.c:318 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x133/0x200 drivers/tty/pty.c:122 process_output_block drivers/tty/n_tty.c:593 [inline] n_tty_write+0x497/0x1220 drivers/tty/n_tty.c:2331 do_tty_write drivers/tty/tty_io.c:959 [inline] tty_write+0x45b/0x7a0 drivers/tty/tty_io.c:1043 __vfs_write+0x116/0xb40 fs/read_write.c:485 vfs_write+0x20c/0x580 fs/read_write.c:549 ksys_write+0x105/0x260 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f314b444c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f314b444c90 RCX: 0000000000457ec9 RDX: 0000000000001006 RSI: 0000000020001640 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f314b4456d4 R13: 00000000004c6ec1 R14: 00000000004dc3b8 R15: 0000000000000007 kobject: 'loop3' (000000005a97e348): kobject_uevent_env 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+0x1db/0x2d0 lib/dump_stack.c:113 kobject: 'loop3' (000000005a97e348): fill_kobj_path: path = '/devices/virtual/block/loop3' panic+0x2cb/0x589 kernel/panic.c:189 bridge0: port 1(bridge_slave_0) entered blocking state kobject: 'loop4' (00000000c303907a): kobject_uevent_env kobject: 'loop4' (00000000c303907a): fill_kobj_path: path = '/devices/virtual/block/loop4' kobject: 'loop3' (000000005a97e348): kobject_uevent_env __warn.cold+0x20/0x4b kernel/panic.c:544 report_bug+0x263/0x2b0 lib/bug.c:186 kobject: 'loop3' (000000005a97e348): fill_kobj_path: path = '/devices/virtual/block/loop3' fixup_bug arch/x86/kernel/traps.c:178 [inline] fixup_bug arch/x86/kernel/traps.c:173 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 kobject: 'loop5' (0000000026a6b0d0): kobject_uevent_env invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 RIP: 0010:__lock_downgrade kernel/locking/lockdep.c:3553 [inline] RIP: 0010:lock_downgrade+0x4d2/0x910 kernel/locking/lockdep.c:3816 Code: 00 00 00 fc ff df 41 c6 04 06 f8 e9 1f ff ff ff 48 c7 c7 20 9e 4b 88 4c 89 8d 58 ff ff ff 48 89 85 60 ff ff ff e8 2e 1b e7 ff <0f> 0b 48 8b 85 60 ff ff ff 4c 8d 5d d8 4c 89 f1 48 ba 00 00 00 00 kobject: 'loop5' (0000000026a6b0d0): fill_kobj_path: path = '/devices/virtual/block/loop5' RSP: 0018:ffff888056c1fbb8 EFLAGS: 00010082 kobject: 'loop5' (0000000026a6b0d0): kobject_uevent_env RAX: 0000000000000000 RBX: 1ffff1100ad83f7d RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8167dbb6 RDI: 0000000000000006 RBP: ffff888056c1fc70 R08: ffff88804f9cc480 R09: fffffbfff1332979 R10: fffffbfff1332978 R11: ffffffff89994bc3 R12: ffff88804f9cc480 R13: ffffffff8b55b960 R14: ffff888056c1fc08 R15: 0000000000000001 kobject: 'loop5' (0000000026a6b0d0): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop5' (0000000026a6b0d0): kobject_uevent_env downgrade_write+0x76/0x270 kernel/locking/rwsem.c:147 kobject: 'loop5' (0000000026a6b0d0): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'loop4' (00000000c303907a): kobject_uevent_env kobject: 'loop4' (00000000c303907a): fill_kobj_path: path = '/devices/virtual/block/loop4' __do_munmap+0xc33/0xed0 mm/mmap.c:2823 __vm_munmap+0x139/0x1f0 mm/mmap.c:2848 kobject: 'loop3' (000000005a97e348): kobject_uevent_env kobject: 'loop3' (000000005a97e348): fill_kobj_path: path = '/devices/virtual/block/loop3' __do_sys_munmap mm/mmap.c:2873 [inline] __se_sys_munmap mm/mmap.c:2870 [inline] __x64_sys_munmap+0x67/0x80 mm/mmap.c:2870 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fe0e6cac417 Code: f0 ff ff 73 01 c3 48 8d 0d 8a ad 20 00 31 d2 48 29 c2 89 11 48 83 c8 ff eb eb 90 90 90 90 90 90 90 90 90 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8d 0d 5d ad 20 00 31 d2 48 29 c2 89 RSP: 002b:00007ffc5aa21148 EFLAGS: 00000203 ORIG_RAX: 000000000000000b RAX: ffffffffffffffda RBX: 00007fe0e6eb71c8 RCX: 00007fe0e6cac417 RDX: 0000000000111b00 RSI: 00000000000033ef RDI: 00007fe0e6eaf000 RBP: 00007ffc5aa212b0 R08: 0000000000000001 R09: 0000000000000007 R10: 00007fe0e6ca6a0b R11: 0000000000000203 R12: 00000000b1b9dd37 R13: 00000289b1b9dd37 R14: 00000289b1aa76d9 R15: 00007fe0e6eac740 Kernel Offset: disabled Rebooting in 86400 seconds..