Re: [PATCH] xen/arm: irq: Initialize the per-CPU IRQs while preparing the CPU

[Julien Grall <julien@xxxxxxx>]

On 14/06/2022 12:05, Michal Orzel wrote:
> Hi Julien,
>
> On 14.06.2022 11:41, Julien Grall wrote:
> > From: Julien Grall <jgrall@xxxxxxxxxx>
> >
> > Commit 5047cd1d5dea "xen/common: Use enhanced ASSERT_ALLOC_CONTEXT in
> > xmalloc()" extended the checks in _xmalloc() to catch any use of the
> > helpers from context with interrupts disabled.
> >
> > Unfortunately, the rule is not followed when initializing the per-CPU
> > IRQs:
> >
> > (XEN) Xen call trace:
> > (XEN)    [<002389f4>] _xmalloc+0xfc/0x314 (PC)
> > (XEN)    [<00000000>] 00000000 (LR)
> > (XEN)    [<0021a7c4>] init_one_irq_desc+0x48/0xd0
> > (XEN)    [<002807a8>] irq.c#init_local_irq_data+0x48/0xa4
> > (XEN)    [<00280834>] init_secondary_IRQ+0x10/0x2c
> > (XEN)    [<00288fa4>] start_secondary+0x194/0x274
> > (XEN)    [<40010170>] 40010170
> > (XEN)
> > (XEN)
> > (XEN) ****************************************
> > (XEN) Panic on CPU 2:
> > (XEN) Assertion '!in_irq() && (local_irq_is_enabled() || num_online_cpus() <= 
> > 1)' failed at common/xmalloc_tlsf.c:601
> > (XEN) ****************************************
> >
> > This is happening because zalloc_cpumask_var() may allocate memory
> > if NR_CPUS is > 2 * sizeof(unsigned long).
> >
> > Avoid the problem by allocate the per-CPU IRQs while preparing the
> > CPU.
> Shouldn't this be" by initializing the per-CPU IRQs while ..." ?
I am fine with using "initializing" rather than "allocating".

> Either way this text is the same like in the previous patch so I think this is 
> not correct.
I can't quite parse this.

> Other than that:
> Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
Thanks!

Cheers,

--
Julien Grall