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SubjectRe: [PATCH] kernel: panic: make panic() local lock raw
On Fri, 11 Mar 2016 18:48:25 +0100 Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote:

> The lock is taken with disabled interrupts and therefore it must be
> a RAW lock. Otherwise -RT will convert it into a sleeping lock and
> complain about it.

panic_lock doesn't exist in current kernels.

However you may want to take a look at pause_on_oops_lock - strange
things are happening with IRQs there.

> --- a/kernel/panic.c
> +++ b/kernel/panic.c
> @@ -71,7 +71,7 @@ void __weak panic_smp_self_stop(void)
> */
> void panic(const char *fmt, ...)
> {
> - static DEFINE_SPINLOCK(panic_lock);
> + static DEFINE_RAW_SPINLOCK(panic_lock);

This should have had a comment explaining why a raw spinlock was chosen.

> static char buf[1024];
> va_list args;
> long i, i_next = 0;
> @@ -95,7 +95,7 @@ void panic(const char *fmt, ...)
> * stop themself or will wait until they are stopped by the 1st CPU
> * with smp_send_stop().
> */
> - if (!spin_trylock(&panic_lock))
> + if (!raw_spin_trylock(&panic_lock))
> panic_smp_self_stop();
>
> console_verbose();

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