Re: [PATCH 01/12] cachefiles: remove request from xarry during flush requests

[Jingbo Xu]

On 4/24/24 11:39 AM, libao...@huaweicloud.com wrote:
> From: Baokun Li <libaok...@huawei.com>
> 
> This prevents concurrency from causing access to a freed req.

Could you give more details on how the concurrent access will happen?
How could another process access the &cache->reqs xarray after it has
been flushed?

> ---
>  fs/cachefiles/daemon.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
> index 6465e2574230..ccb7b707ea4b 100644
> --- a/fs/cachefiles/daemon.c
> +++ b/fs/cachefiles/daemon.c
> @@ -159,6 +159,7 @@ static void cachefiles_flush_reqs(struct cachefiles_cache 
> *cache)
>       xa_for_each(xa, index, req) {
>               req->error = -EIO;
>               complete(&req->done);
> +             __xa_erase(xa, index);
>       }
>       xa_unlock(xa);
>  

-- 
Thanks,
Jingbo