Messages in this thread | | | From | Sven Schnelle <> | Subject | Re: [PATCH 1/2] sched/idle: Fix arch_cpu_idle() vs tracing | Date | Tue, 01 Dec 2020 12:56:27 +0100 |
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Hi Peter,
Peter Zijlstra <peterz@infradead.org> writes:
> On Mon, Nov 30, 2020 at 01:00:03PM -0800, Guenter Roeck wrote: >> On Fri, Nov 20, 2020 at 12:41:46PM +0100, Peter Zijlstra wrote: >> > We call arch_cpu_idle() with RCU disabled, but then use >> > local_irq_{en,dis}able(), which invokes tracing, which relies on RCU. >> > >> > Switch all arch_cpu_idle() implementations to use >> > raw_local_irq_{en,dis}able() and carefully manage the >> > lockdep,rcu,tracing state like we do in entry. >> > >> > (XXX: we really should change arch_cpu_idle() to not return with >> > interrupts enabled) >> > >> >> Has this patch been tested on s390 ? Reason for asking is that it causes >> all my s390 emulations to crash. Reverting it fixes the problem. > > My understanding is that it changes the error on s390. Previously it > would complain about the local_irq_enable() in arch_cpu_idle(), now it > complains when taking an interrupt during idle.
I looked into adding the required functionality for s390, but the code we would need to add to entry.S is rather large - as you noted we would have to duplicate large portions of irqentry_enter() into our code. Given that s390 was fine before that patch, can you revert it and submit it again during the next merge window?
Thanks Sven
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