Re: possible deadlock in __ata_sff_interrupt

[Al Viro]

On Thu, Dec 15, 2022 at 06:48:20PM +0900, Damien Le Moal wrote:

> The problem is here: sg_rq_end_io() calling kill_fasync(). But at a quick
> glance, this is not the only driver calling kill_fasync() with a spinlock
> held with irq disabled... So there may be a fundamental problem with
> kill_fasync() function if drivers are allowed to do that, or the reverse,
> all drivers calling that function with a lock held with irq disabled need
> to be fixed.
> 
> Al, Chuck, Jeff,
> 
> Any thought ?

What is the problem with read_lock_irqsave() called with irqs disabled?
read_lock_irq() would have been a bug in such conditions, of course, but
that's not what we use...