From: Jann Horn <jannh@google.com>
To: Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org
Cc: 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: [PATCH 4/4] mm/gup: Assert that the mmap lock is held in __get_user_pages()
Date: Tue, 29 Sep 2020 18:20:01 -0700 [thread overview]
Message-ID: <CAG48ez1GM==OnHpS=ghqZNJPn02FCDUEHc7GQmGRMXUD_aKudg@mail.gmail.com> (raw)
In-Reply-To: <20200930011944.19869-1-jannh@google.com>
After having cleaned up all GUP callers (except for the atomisp staging
driver, which currently gets mmap locking completely wrong [1]) to always
ensure that they hold the mmap lock when calling into GUP (unless the mm is
not yet globally visible), add an assertion to make sure it stays that way
going forward.
[1] https://lore.kernel.org/lkml/CAG48ez3tZAb9JVhw4T5e-i=h2_DUZxfNRTDsagSRCVazNXx5qA@mail.gmail.com/
Signed-off-by: Jann Horn <jannh@google.com>
---
mm/gup.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/gup.c b/mm/gup.c
index f11d39867cf5..3e5d843215b9 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1020,6 +1020,8 @@ static long __get_user_pages(struct mm_struct *mm,
struct vm_area_struct *vma = NULL;
struct follow_page_context ctx = { NULL };
+ mmap_assert_locked(mm);
+
if (!nr_pages)
return 0;
--
2.28.0.709.gb0816b6eb0-goog
next prev parent reply other threads:[~2020-09-30 1:20 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
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 ` Jann Horn [this message]
2020-09-30 12:32 ` [PATCH 4/4] mm/gup: Assert that the mmap lock is held in __get_user_pages() Jason Gunthorpe
2020-09-30 23:24 ` Michel Lespinasse
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAG48ez1GM==OnHpS=ghqZNJPn02FCDUEHc7GQmGRMXUD_aKudg@mail.gmail.com' \
--to=jannh@google.com \
--cc=akpm@linux-foundation.org \
--cc=ebiederm@xmission.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mchehab@kernel.org \
--cc=sakari.ailus@linux.intel.com \
--cc=walken@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).