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

Sergey Senozhatsky
2022-06-14T02:51:51Z

On (22/06/13 17:54), Alexandru Elisei wrote:
[..]
> [ 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.

Hmm, interesting and puzzling.

If you disable console kthreads (__printk_fallback_preferred_direct) and
keep 10e14073107d, are you able to successfully boot the board or does it
boot to a panic?

> 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().

Is it console lock (console_kthreads_block() -> mutex_lock(&con->lock))
that we cannot grab or is it console semaphore?