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

Linus Torvalds torvalds at linux-foundation.org
Fri Sep 29 03:26:15 UTC 2017

On Thu, Sep 28, 2017 at 6:53 PM, Mimi Zohar <zohar at linux.vnet.ibm.com> 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


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

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