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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Jann Horn <jannh@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	Michel Lespinasse <walken@google.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Sakari Ailus <sakari.ailus@linux.intel.com>
Subject: Re: [PATCH 3/4] mmap locking API: Don't check locking if the mm isn't live yet
Date: Wed, 30 Sep 2020 09:30:00 -0300	[thread overview]
Message-ID: <20200930123000.GC9916@ziepe.ca> (raw)
In-Reply-To: <CAG48ez03YJG9JU_6tGiMcaVjuTyRE_o4LEQ7901b5ZoCnNAjcg@mail.gmail.com>

On Tue, Sep 29, 2020 at 06:20:00PM -0700, Jann Horn wrote:
> In preparation for adding a mmap_assert_locked() check in
> __get_user_pages(), teach the mmap_assert_*locked() helpers that it's fine
> to operate on an mm without locking in the middle of execve() as long as
> it hasn't been installed on a process yet.

I'm happy to see lockdep being added here, but can you elaborate on
why add this mmap_locked_required instead of obtaining the lock in the
execv path?

Jason


  reply	other threads:[~2020-09-30 12:30 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200930011944.19869-1-jannh@google.com>
2020-09-30  1:20 ` [PATCH 2/4] binfmt_elf: Take the mmap lock around find_extend_vma() Jann Horn
2020-09-30 23:22   ` Michel Lespinasse
2020-09-30  1:20 ` [PATCH 3/4] mmap locking API: Don't check locking if the mm isn't live yet Jann Horn
2020-09-30 12:30   ` Jason Gunthorpe [this message]
2020-09-30 12:50     ` Jann Horn
2020-09-30 20:14       ` Jann Horn
2020-09-30 23:26         ` Jason Gunthorpe
2020-09-30 23:51           ` Jann Horn
2020-10-01 19:15             ` Jason Gunthorpe
2020-10-01 20:16               ` Jann Horn
2020-10-01 23:41                 ` Jason Gunthorpe
2020-10-01 23:55                   ` Jann Horn
2020-09-30 23:42         ` Michel Lespinasse
2020-09-30  1:20 ` [PATCH 4/4] mm/gup: Assert that the mmap lock is held in __get_user_pages() Jann Horn
2020-09-30 12:32   ` Jason Gunthorpe
2020-09-30 23:24     ` Michel Lespinasse

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