Re: [PATCH V1] block: Fix null pointer dereference issue on struct io_cq

[Damien Le Moal]

On 5/17/23 18:21, Christoph Hellwig wrote:
> On Wed, May 17, 2023 at 06:20:19PM +0900, Damien Le Moal wrote:
>> twice for the same icq. The missing rcu lock in ioc_exit_icqs() already was in
>> itself a bug, and the missing flag check is another.
> 
> spinlocks imply a rcu critical section, no need to duplicate it.

Right. And I misread the code. As Yu said, given that ioc_exit_icqs() iterates
the list of icqs under ioc->lock and the ioc is removed from that list under the
same lock, ioc_exit_icqs() should never see an icq that went through
ioc_destroy_icq()...
Very weird.


-- 
Damien Le Moal
Western Digital Research