lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Fri, 15 Oct 2021 06:19:18 -0700
From:   Christoph Hellwig <>
To:     Matthew Wilcox <>
Cc:     Zqiang <>,,,,,,
        Mikulas Patocka <>,
        Jens Axboe <>, Tejun Heo <>
Subject: Re: [PATCH] mm: backing-dev: use kfree_rcu() instead of

On Fri, Oct 15, 2021 at 01:35:56PM +0100, Matthew Wilcox wrote:
>  struct backing_dev_info {
>         u64 id;
> -       struct rb_node rb_node; /* keyed by ->id */
> +       union {
> +               struct rb_node rb_node; /* keyed by ->id */
> +               struct rcu_head rcu;
> +       };
>         struct list_head bdi_list;
>         unsigned long ra_pages; /* max readahead in PAGE_SIZE units */
>         unsigned long io_pages; /* max allowed IO size */
> Christoph, independent of the inode lifetime problem, this actually seems
> like a good approach to take.  I don't see why we should synchronize_rcu()
> here?  Adding Jens (original introducer of the synchronize_rcu()), Mikulas
> (converted it to use _expedited) and Tejun (worked around a problem when
> using _expedited).

The kfree+rcu + your suggestion does seem like a good idea in general to
me.  But I'd still like to fix the actual bug being reported before
optimizing the area in a way that papers over the bug.

Powered by blists - more mailing lists