Re: [PATCH v1 1/2] arm64: run softirqs on the per-CPU IRQ stack

From: Arnd Bergmann
Date: Thu Jul 14 2022 - 07:32:57 EST


On Fri, Jul 8, 2022 at 11:49 AM Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> wrote:
>
> Currently arm64 supports per-CPU IRQ stack, but softirqs
> are still handled in the task context.
>
> Since any call to local_bh_enable() at any level in the task's
> call stack may trigger a softirq processing run, which could
> potentially cause a task stack overflow if the combined stack
> footprints exceed the stack's size, let's run these softirqs
> on the IRQ stack as well.
>
> Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>

This seems like a nice improvement, and this version addresses
my concern I raised on the RFC version.

Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>