Greeting,

FYI, we noticed the following commit (built with gcc-9):

commit: 679193b7baf8d88e41cbeb397ca17f797654947d ("serial: 8250: Let serial core initialise spin lock")
https://git.kernel.org/cgit/linux/kernel/git/gregkh/tty.git tty-next


in testcase: boot

on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):


+-------------------------------+------------+------------+
|                               | f3af1b68fc | 679193b7ba |
+-------------------------------+------------+------------+
| boot_successes                | 4          | 0          |
| boot_failures                 | 0          | 4          |
| BUG:spinlock_bad_magic_on_CPU | 0          | 4          |
+-------------------------------+------------+------------+


If you fix the issue, kindly add following tag
Reported-by: kernel test robot <lkp@intel.com>


[    0.679698] BUG: spinlock bad magic on CPU#0, swapper/0/0
[    0.681031]  lock: serial8250_ports+0x0/0x7000, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
[    0.683364] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.8.0-rc7-00089-g679193b7baf8d8 #3
[    0.685316] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[    0.687206] Call Trace:
[    0.687933]  dump_stack+0x96/0xd0
[    0.688733]  do_raw_spin_lock+0x72/0xc0
[    0.689738]  _raw_spin_lock_irqsave+0x4f/0x60
[    0.690833]  ? serial8250_do_set_termios+0x118/0x460
[    0.692034]  serial8250_do_set_termios+0x118/0x460
[    0.693193]  uart_set_options+0x100/0x150
[    0.694237]  serial8250_console_setup+0x96/0x1a0
[    0.695386]  univ8250_console_setup+0x52/0x80
[    0.696495]  try_enable_new_console+0x82/0xf0
[    0.697591]  ? serial8250_isa_init_ports+0x1c6/0x1c6
[    0.698930]  register_console+0xcd/0x280
[    0.700069]  ? serial8250_isa_init_ports+0x1c6/0x1c6
[    0.701412]  univ8250_console_init+0x24/0x27
[    0.702561]  console_init+0x1ae/0x282
[    0.703500]  start_kernel+0x4ff/0x664
[    0.704489]  secondary_startup_64+0xb6/0xc0
[    0.705556] printk: console [ttyS0] enabled
[    0.707307] printk: bootconsole [earlyser0] disabled
[    0.709464] Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar
[    0.711666] ... MAX_LOCKDEP_SUBCLASSES:  8
[    0.712856] ... MAX_LOCK_DEPTH:          48
[    0.714080] ... MAX_LOCKDEP_KEYS:        8192
[    0.715318] ... CLASSHASH_SIZE:          4096
[    0.716572] ... MAX_LOCKDEP_ENTRIES:     32768
[    0.717837] ... MAX_LOCKDEP_CHAINS:      65536
[    0.718990] ... CHAINHASH_SIZE:          32768
[    0.720066]  memory used by lock dependency info: 6301 kB
[    0.721338]  memory used for stack traces: 4224 kB
[    0.722656]  per task-struct memory footprint: 1920 bytes
[    0.724175] ACPI: Core revision 20200528
[    0.725601] clocksource: hpet: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604467 ns
[    0.728055] APIC: Switch to symmetric I/O mode setup
[    0.729759] x2apic enabled
[    0.731093] Switched APIC routing to physical x2apic.
[    0.732576] masked ExtINT on CPU#0
[    0.734651] ENABLING IO-APIC IRQs
[    0.735607] init IO_APIC IRQs
[    0.736571]  apic 0 pin 0 not connected
[    0.737760] IOAPIC[0]: Set routing entry (0-1 -> 0xef -> IRQ 1 Mode:0 Active:0 Dest:0)
[    0.739964] IOAPIC[0]: Set routing entry (0-2 -> 0x30 -> IRQ 0 Mode:0 Active:0 Dest:0)
[    0.742292] IOAPIC[0]: Set routing entry (0-3 -> 0xef -> IRQ 3 Mode:0 Active:0 Dest:0)
[    0.744585] IOAPIC[0]: Set routing entry (0-4 -> 0xef -> IRQ 4 Mode:0 Active:0 Dest:0)
[    0.746724] IOAPIC[0]: Set routing entry (0-5 -> 0xef -> IRQ 5 Mode:1 Active:0 Dest:0)
[    0.748769] IOAPIC[0]: Set routing entry (0-6 -> 0xef -> IRQ 6 Mode:0 Active:0 Dest:0)
[    0.751063] IOAPIC[0]: Set routing entry (0-7 -> 0xef -> IRQ 7 Mode:0 Active:0 Dest:0)
[    0.753411] IOAPIC[0]: Set routing entry (0-8 -> 0xef -> IRQ 8 Mode:0 Active:0 Dest:0)
[    0.755576] IOAPIC[0]: Set routing entry (0-9 -> 0xef -> IRQ 9 Mode:1 Active:0 Dest:0)
[    0.757708] IOAPIC[0]: Set routing entry (0-10 -> 0xef -> IRQ 10 Mode:1 Active:0 Dest:0)
[    0.759917] IOAPIC[0]: Set routing entry (0-11 -> 0xef -> IRQ 11 Mode:1 Active:0 Dest:0)
[    0.762093] IOAPIC[0]: Set routing entry (0-12 -> 0xef -> IRQ 12 Mode:0 Active:0 Dest:0)
[    0.764270] IOAPIC[0]: Set routing entry (0-13 -> 0xef -> IRQ 13 Mode:0 Active:0 Dest:0)
[    0.766476] IOAPIC[0]: Set routing entry (0-14 -> 0xef -> IRQ 14 Mode:0 Active:0 Dest:0)
[    0.768578] IOAPIC[0]: Set routing entry (0-15 -> 0xef -> IRQ 15 Mode:0 Active:0 Dest:0)
[    0.770698]  apic 0 pin 16 not connected
[    0.771728]  apic 0 pin 17 not connected
[    0.772763]  apic 0 pin 18 not connected
[    0.773840]  apic 0 pin 19 not connected
[    0.774908]  apic 0 pin 20 not connected
[    0.775848]  apic 0 pin 21 not connected
[    0.776812]  apic 0 pin 22 not connected
[    0.777830]  apic 0 pin 23 not connected
[    0.779059] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
[    0.780458] clocksource: tsc-early: mask: 0xffffffffffffffff max_cycles: 0x29b38900952, max_idle_ns: 440795323692 ns
[    0.782965] Calibrating delay loop (skipped) preset value.. 5786.05 BogoMIPS (lpj=2893028)
[    0.783967] pid_max: default: 32768 minimum: 301
[    0.785033] LSM: Security Framework initializing
[    0.785973] Yama: becoming mindful.
[    0.787068] Mount-cache hash table entries: 32768 (order: 6, 262144 bytes, linear)
[    0.789000] Mountpoint-cache hash table entries: 32768 (order: 6, 262144 bytes, linear)
Poking KASLR using RDTSC...
[    0.791631] Last level iTLB entries: 4KB 0, 2MB 0, 4MB 0
[    0.791974] Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0, 1GB 0
[    0.792976] Spectre V1 : Mitigation: usercopy/swapgs barriers and __user pointer sanitization
[    0.794976] Spectre V2 : Mitigation: Full generic retpoline
[    0.795964] Spectre V2 : Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch
[    0.796967] Speculative Store Bypass: Vulnerable
[    0.797974] MDS: Vulnerable: Clear CPU buffers attempted, no microcode
[    0.800025] Freeing SMP alternatives memory: 40K
[    0.802607] smpboot: CPU0: Intel Xeon E312xx (Sandy Bridge) (family: 0x6, model: 0x2a, stepping: 0x1)
[    0.803397] Performance Events: unsupported p6 CPU model 42 no PMU driver, software events only.
[    0.804132] rcu: Hierarchical SRCU implementation.
[    0.806152] NMI watchdog: Perf NMI watchdog permanently disabled
[    0.807192] smp: Bringing up secondary CPUs ...
[    0.808338] x86: Booting SMP configuration:
[    0.808982] .... node  #0, CPUs:      #1
[    0.217301] kvm-clock: cpu 1, msr 27da01041, secondary cpu clock
[    0.217301] masked ExtINT on CPU#1
[    0.217301] smpboot: CPU 1 Converting physical 0 to logical die 1
[    0.831177] KVM setup async PF for cpu 1
[    0.831958] kvm-stealtime: cpu 1, msr 42fd30080
[    0.832082] smp: Brought up 1 node, 2 CPUs
[    0.832994] smpboot: Max logical packages: 2
[    0.833975] smpboot: Total of 2 processors activated (11572.11 BogoMIPS)
[    0.878607] node 0 deferred pages initialised in 43ms
[    0.880661] devtmpfs: initialized
[    0.881135] x86/mm: Memory block size: 128MB


To reproduce:

        # build kernel
	cd linux
	cp config-5.8.0-rc7-00089-g679193b7baf8d8 .config
	make HOSTCC=gcc-9 CC=gcc-9 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email



Thanks,
lkp