Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively

[Linus Torvalds]

On Thu, Sep 28, 2017 at 6:53 PM, Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx> wrote:
>
> The locking issue isn't with validating the file hash, but with the
> setxattr, chmod, chown syscalls.  Each of these syscalls takes the
> i_rwsem exclusively before IMA (or EVM) is called.

Read my email again.

> In setxattr, chmod, chown syscalls, IMA (and EVM) are called after the
> i_rwsem is already taken.  So the locking would be:
>
> lock: i_rwsem
> lock: iint->mutex

No.

Two locks. One inner, one outer. Only the actual ones that calculates
the hash would take the outer one. Read my email.

           Linus