Re: [GIT PULL] RCU changes for v7.1

[Paul E. McKenney]

On Mon, Apr 13, 2026 at 12:38:32PM -0700, Linus Torvalds wrote:
> On Mon, 13 Apr 2026 at 11:03, Paul E. McKenney <paulmck@xxxxxxxxxx> wrote:
> >
> > Apologies!  Would making this instead be a kernel boot parameter be
> > acceptable?
> 
> We already have a sysctl for it, and you should *already* be able to
> use a boot parameter for it with just
> 
>         sysctl.kernel.panic_on_rcu_stall=true

Thank you, and testing is in progress.

> Not that I've tried it, so maybe there's some bug somewhere (or
> something I've overlooked), but I really think the whole kernel config
> option was entirely redundant to begin with.

Given recent improvements to bootconfig, using the sysctl kernel boot
parameter should be just fine.

Before those improvements, associating particular kernel boot parameters
with all kernels was often problematic in large sets of datacenters.
Even worse were cases where kernel boot parameters needed to be set
differently for different kernel versions.  But for most kernel boot
parameters (including this one), things should be fine now.

More work is needed for early boot parameters, and that is in progress.

In this case, I simply failed to get all the pieces in my head at the
same time.  In particular, I forgot that you can specify kernel boot
parameters for sysctls.  :-/

							Thanx, Paul