On Mon, 2007-09-17 at 20:12 +0200, Andi Kleen wrote:
> When the kernel is oopsing no realtime guarantees are needed anymore and sleeping
> here is unsafe; e.g. in case the crash site had interrupts disabled.
>
> - Convert die_lock to a raw spinlock
> - Really disable interrupts
>
> Signed-off-by: Andi Kleen <ak@xxxxxxx>
>
> Index: linux-2.6.23-rc4-rt1/arch/x86_64/kernel/traps.c
> ===================================================================
> --- linux-2.6.23-rc4-rt1.orig/arch/x86_64/kernel/traps.c
> +++ linux-2.6.23-rc4-rt1/arch/x86_64/kernel/traps.c
> @@ -467,7 +467,7 @@ void out_of_line_bug(void)
> EXPORT_SYMBOL(out_of_line_bug);
> #endif
>
> -static DEFINE_SPINLOCK(die_lock);
> +static __raw_spinlock_t die_lock = __RAW_SPIN_LOCK_UNLOCKED;
You mean DEFINE_RAW_SPINLOCK() maybe? Unless I'm not following what your
doing here..
> static int die_owner = -1;
> static unsigned int die_nest_count;
>
> @@ -479,13 +479,13 @@ unsigned __kprobes long oops_begin(void)
> oops_enter();
>
> /* racy, but better than risking deadlock. */
> - local_irq_save(flags);
> + raw_local_irq_save(flags);
local_irq_save() should disable interrupts .. The difference between the
two is one does interrupt off trace accounting
> cpu = smp_processor_id();
> - if (!spin_trylock(&die_lock)) {
> + if (!__raw_spin_trylock(&die_lock)) {
If you use DEFINE_RAW_SPINLOCK() above you shouldn't need to mod these
individually .. A call to spin_trylock() will automatically change
depending on the lock type.
Daniel
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