Re: [PATCH] powerpc/eeh_cache: Fix a possible debugfs deadlock

[Michael Ellerman]

On Wed, 28 Oct 2020 11:27:17 -0400, Qian Cai wrote:
> Lockdep complains that a possible deadlock below in
> eeh_addr_cache_show() because it is acquiring a lock with IRQ enabled,
> but eeh_addr_cache_insert_dev() needs to acquire the same lock with IRQ
> disabled. Let's just make eeh_addr_cache_show() acquire the lock with
> IRQ disabled as well.
> 
>         CPU0                    CPU1
>         ----                    ----
>    lock(&pci_io_addr_cache_root.piar_lock);
>                                 local_irq_disable();
>                                 lock(&tp->lock);
>                                 lock(&pci_io_addr_cache_root.piar_lock);
>    <Interrupt>
>      lock(&tp->lock);
> 
> [...]

Applied to powerpc/fixes.

[1/1] powerpc/eeh_cache: Fix a possible debugfs deadlock
      https://git.kernel.org/powerpc/c/fd552e0542b4532483289cce48fdbd27b692984b

cheers