lkml.org 
[lkml]   [2020]   [Mar]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 0/2] Make printk_deferred() work properly before percpu setup is done
On (20/03/26 17:32), Jann Horn wrote:
> While I was doing some development work, I noticed that if you call
> printk_deferred() before percpu setup has finished, stuff breaks, and
> e.g. "dmesg -w" fails to print new messages.
>
> This happens because writing to percpu memory before percpu
> initialization is done causes the modified percpu memory to be
> propagated from the boot CPU to all the secondary CPUs; and both the
> printk code as well as the irq_work implementation use percpu memory.
>
> I think that printk_deferred() ought to work even before percpu
> initialization, since it is used by things like pr_warn_ratelimited()
> and the unwinder infrastructure. I'm not entirely sure though whether
> this is the best way to implement that, or whether it would be better to
> let printk_deferred() do something different if it is called during
> early boot.

Hi Jann,

I believe we have a patch for this issue

https://lore.kernel.org/lkml/20200303113002.63089-1-sergey.senozhatsky@gmail.com/

-ss

\
 
 \ /
  Last update: 2020-03-27 03:45    [W:0.050 / U:10.412 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site