[BUG] rockpro64 board hangs in console_init() after commit 10e14073107d

[Alexandru Elisei]

Hi,

(Apologies for the long To: list, I've added everyone that
scripts/get_maintainer.pl listed for fs/{fs-writeback,inode}.c, for the
rockchip boards, for printk.c and for the tty layer)

When booting a kernel built from tag v5.19-rc2, my rockpro64-v2 hangs at
boot with this log:

[    0.000000] Booting Linux on physical CPU 0x0000000000 [0x410fd034]
[    0.000000] Linux version 5.19.0-rc2 (alex at redacted) (aarch64-linux-gnu-gcc (GCC) 12.1.0, GNU ld (GNU Binutils) 2.38) #90 SMP PREEMPT Mon Jun 13 17:13:12 BST 2022
[    0.000000] Machine model: Pine64 RockPro64 v2.0
[    0.000000] efi: UEFI not found.
[    0.000000] earlycon: uart0 at MMIO32 0x00000000ff1a0000 (options '1500000n8')
[    0.000000] printk: bootconsole [uart0] enabled
[    0.000000] NUMA: No NUMA configuration found
[    0.000000] NUMA: Faking a node at [mem 0x0000000000200000-0x00000000f7ffffff]
[    0.000000] NUMA: NODE_DATA [mem 0xf77dc140-0xf77ddfff]
[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x0000000000200000-0x00000000f7ffffff]
[    0.000000]   DMA32    empty
[    0.000000]   Normal   empty
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000000200000-0x00000000f7ffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000000200000-0x00000000f7ffffff]
[    0.000000] On node 0, zone DMA: 512 pages in unavailable ranges
[    0.000000] cma: Reserved 32 MiB at 0x00000000f0000000
[    0.000000] psci: probing for conduit method from DT.
[    0.000000] psci: PSCIv1.1 detected in firmware.
[    0.000000] psci: Using standard PSCI v0.2 function IDs
[    0.000000] psci: MIGRATE_INFO_TYPE not supported.
[    0.000000] psci: SMC Calling Convention v1.2
[    0.000000] percpu: Embedded 20 pages/cpu s41768 r8192 d31960 u81920
[    0.000000] Detected VIPT I-cache on CPU0
[    0.000000] CPU features: detected: GIC system register CPU interface
[    0.000000] CPU features: detected: ARM erratum 845719
[    0.000000] Fallback order for Node 0: 0
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 999432
[    0.000000] Policy zone: DMA
[    0.000000] Kernel command line: root=PARTUUID=7f4aab92-69d8-47f3-be10-624da40a71f9 rw earlycon rootwait
[    0.000000] Dentry cache hash table entries: 524288 (order: 10, 4194304 bytes, linear)
[    0.000000] Inode-cache hash table entries: 262144 (order: 9, 2097152 bytes, linear)
[    0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[    0.000000] Memory: 3915796K/4061184K available (15552K kernel code, 2758K rwdata, 8668K rodata, 6336K init, 564K bss, 112620K reserved, 32768K cma-reserved)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=6, Nodes=1
[    0.000000] rcu: Preemptible hierarchical RCU implementation.
[    0.000000] rcu: 	RCU event tracing is enabled.
[    0.000000] rcu: 	RCU restricting CPUs from NR_CPUS=256 to nr_cpu_ids=6.
[    0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 25 jiffies.
[    0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=6
[    0.000000] NR_IRQS: 64, nr_irqs: 64, preallocated irqs: 0
[    0.000000] GICv3: GIC: Using split EOI/Deactivate mode
[    0.000000] GICv3: 256 SPIs implemented
[    0.000000] GICv3: 0 Extended SPIs implemented
[    0.000000] Root IRQ handler: gic_handle_irq
[    0.000000] GICv3: GICv3 features: 16 PPIs
[    0.000000] GICv3: CPU0: found redistributor 0 region 0:0x00000000fef00000
[    0.000000] ITS [mem 0xfee20000-0xfee3ffff]
[    0.000000] ITS at 0x00000000fee20000: allocated 65536 Devices @480000 (flat, esz 8, psz 64K, shr 0)
[    0.000000] ITS: using cache flushing for cmd queue
[    0.000000] GICv3: using LPI property table @0x0000000000440000
[    0.000000] GIC: using cache flushing for LPI property table
[    0.000000] GICv3: CPU0: using allocated LPI pending table @0x0000000000450000
[    0.000000] GICv3: GIC: PPI partition interrupt-partition-0[0] { /cpus/cpu at 0[0] /cpus/cpu at 1[1] /cpus/cpu at 2[2] /cpus/cpu at 3[3] }
[    0.000000] GICv3: GIC: PPI partition interrupt-partition-1[1] { /cpus/cpu at 100[4] /cpus/cpu at 101[5] }
[    0.000000] rcu: srcu_init: Setting srcu_struct sizes based on contention.
[    0.000000] arch_timer: cp15 timer(s) running at 24.00MHz (phys).
[    0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x588fe9dc0, max_idle_ns: 440795202592 ns
[    0.000001] sched_clock: 56 bits at 24MHz, resolution 41ns, wraps every 4398046511097ns
[    0.005107] Console: colour dummy device 80x25
[    0.005549] printk: console [tty0] enabled
[    0.005956] printk: bootconsole [uart0] disabled

Config can be found at [1] (expires after 6 months). I've also built the
kernel with gcc 10.3.1 [2] (aarch64-none-linux-gnu), same issue.

I've bisected the build failure to commit 10e14073107d ("writeback: Fix
inode->i_io_list not be protected by inode->i_lock error"); I've confirmed
that that commit is responsible by successfully booting the board with a
kernel built from v5.19-rc2 + the above commit reverted.

I tried to do some investigating, it seems that the kernel is stuck at
printk.c::console_init() -> drivers/tty/vt/vt.c::con_init() ->
printk.c::register_console() -> unregister_console() -> console_lock().
This has been determined by adding pr_info statements.

I've booted a kernel compiled with CONFIG_PROVE_LOCKING=y, as the offending
commit fiddles with locks, but no splat was produced that would explain the
hang. I've also tried to boot a v5,19-rc2 kernel on my odroid-c4, the board
is booting just fine, so I'm guessing it only affects of subset of arm64
boards.

[1] https://pastebin.com/MfDrKyKd
[2] https://developer.arm.com/downloads/-/gnu-a

Thanks,
Alex