Re: [PATCH v2 01/26] genirq: add irq_domain-aware core IRQ handler

Stephen Boyd
2014-08-26T18:46:38Z

On 08/26/14 11:07, Marc Zyngier wrote:
> Digging into my email, one of the traces looked like this:
>
> stack backtrace:
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.16.0-rc1+ #135
> Call trace:
> [<ffffffc0000882cc>] dump_backtrace+0x0/0x12c
> [<ffffffc000088408>] show_stack+0x10/0x1c
> [<ffffffc0004ee5f0>] dump_stack+0x74/0xc4
> [<ffffffc0000edfbc>] lockdep_rcu_suspicious+0xe8/0x124
> [<ffffffc00010218c>] irq_find_mapping+0x16c/0x198
> [<ffffffc00008130c>] gic_handle_irq+0x38/0xcc
>
> Most drivers call irq_find_mapping outside of irq_enter()/irq_exit(), as
> this is in handle_IRQ().
>

Ah ok. This is the multi-irq handler case? Has this been broken since
v3.2 at least for the gic users? Now that we call irq_enter()/irq_exit()
a lot more code runs, including things like updating jiffies when
interrupts arrive and invoking softirq? Do we only call irq_exit() on
the IPI path otherwise?

Are there any plans to send this back to stable trees? Not calling
irq_enter()/irq_exit() when we get an interrupt seems like a big problem.

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