Re: [RFC PATCH] nmi,printk: fix ABBA deadlock between nmi_backtrace and dump_stack_lvl

From: Rik van Riel
Date: Fri Sep 13 2024 - 13:34:34 EST


On Wed, 2024-07-24 at 17:08 +0200, Petr Mladek wrote:
> On Wed 2024-07-24 16:51:46, John Ogness wrote:
>
>
> I see. I agree that deferring printk on that CPU [0] is the right
> solution.
>
> > [0]
> > https://lore.kernel.org/lkml/87plrcqyii.fsf@xxxxxxxxxxxxxxxxxxxxx
>
Hi Petr,

we have been running with John Ogness's fix (from the mail linked
above) for about a month now, and it has reduced the number of
deadlocks in the Linux kernel in our fleet by maybe 90%, comparing
a kernel with the fix, to a kernel without the fix.

Would it be possible to get John Ogness's fix queued up for merging
in the printk tree, and then later to Linus?

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