From: Jann Horn <jannh@google.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Jason Gunthorpe <jgg@nvidia.com>,
John Hubbard <jhubbard@nvidia.com>,
Linux-MM <linux-mm@kvack.org>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
mm-commits@vger.kernel.org,
Sakari Ailus <sakari.ailus@linux.intel.com>,
Michel Lespinasse <walken@google.com>
Subject: Re: [patch 14/40] mm/gup: assert that the mmap lock is held in __get_user_pages()
Date: Sun, 18 Oct 2020 03:28:32 +0200 [thread overview]
Message-ID: <CAG48ez2bVnsfaTe0L9hiDJTV9jhprJMu0h6vcujUGWTMy_sLFA@mail.gmail.com> (raw)
In-Reply-To: <20201017231418.twQriq6_i%akpm@linux-foundation.org>
On Sun, Oct 18, 2020 at 1:14 AM Andrew Morton <akpm@linux-foundation.org> wrote:
> From: Jann Horn <jannh@google.com>
> Subject: mm/gup: assert that the mmap lock is held in __get_user_pages()
>
> 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.
Please hold this patch until the replacement for the previous patch in
the series (original patch
mmap-locking-api-dont-check-locking-if-the-mm-isnt-live-yet, which you
are already holding back, and which is replaced by the series
https://lore.kernel.org/linux-mm/20201016225713.1971256-1-jannh@google.com/
"Broad write-locking of nascent mm in execve") has gone into the mm
tree.
Otherwise I believe that this mmap_assert_lock() will cause new
lockdep warnings in places like copy_strings().
(Going forward, is there something I should do differently if a
similar issue happens again with a series of patches that has already
landed in the mm tree but where, after further discussion, parts
should be replaced?)
> [1] https://lore.kernel.org/lkml/CAG48ez3tZAb9JVhw4T5e-i=h2_DUZxfNRTDsagSRCVazNXx5qA@mail.gmail.com/
>
> Link: https://lkml.kernel.org/r/CAG48ez1GM==OnHpS=ghqZNJPn02FCDUEHc7GQmGRMXUD_aKudg@mail.gmail.com
> Signed-off-by: Jann Horn <jannh@google.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> Acked-by: Michel Lespinasse <walken@google.com>
> Cc: "Eric W . Biederman" <ebiederm@xmission.com>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
> Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
> mm/gup.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> --- a/mm/gup.c~mm-gup-assert-that-the-mmap-lock-is-held-in-__get_user_pages
> +++ a/mm/gup.c
> @@ -1027,6 +1027,8 @@ static long __get_user_pages(struct mm_s
> struct vm_area_struct *vma = NULL;
> struct follow_page_context ctx = { NULL };
>
> + mmap_assert_locked(mm);
> +
> if (!nr_pages)
> return 0;
>
> _
next prev parent reply other threads:[~2020-10-18 1:29 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-17 23:13 incoming Andrew Morton
2020-10-17 23:13 ` [patch 01/40] ia64: fix build error with !COREDUMP Andrew Morton
2020-10-17 23:13 ` [patch 02/40] mm, memcg: rework remote charging API to support nesting Andrew Morton
2020-10-17 23:13 ` [patch 03/40] mm: kmem: move memcg_kmem_bypass() calls to get_mem/obj_cgroup_from_current() Andrew Morton
2020-10-17 23:13 ` [patch 04/40] mm: kmem: remove redundant checks from get_obj_cgroup_from_current() Andrew Morton
2020-10-17 23:13 ` [patch 05/40] mm: kmem: prepare remote memcg charging infra for interrupt contexts Andrew Morton
2020-10-17 23:13 ` [patch 06/40] mm: kmem: enable kernel memcg accounting from " Andrew Morton
2020-10-17 23:13 ` [patch 07/40] mm/memory-failure: remove a wrapper for alloc_migration_target() Andrew Morton
2020-10-17 23:14 ` [patch 08/40] mm/memory_hotplug: " Andrew Morton
2020-10-17 23:14 ` [patch 09/40] mm/migrate: avoid possible unnecessary process right check in kernel_move_pages() Andrew Morton
2020-10-17 23:14 ` [patch 10/40] mm/mmap: add inline vma_next() for readability of mmap code Andrew Morton
2020-10-17 23:14 ` [patch 11/40] mm/mmap: add inline munmap_vma_range() for code readability Andrew Morton
2020-10-17 23:14 ` [patch 12/40] mm/gup_benchmark: take the mmap lock around GUP Andrew Morton
2020-10-17 23:14 ` [patch 13/40] binfmt_elf: take the mmap lock around find_extend_vma() Andrew Morton
2020-10-17 23:14 ` [patch 14/40] mm/gup: assert that the mmap lock is held in __get_user_pages() Andrew Morton
2020-10-18 1:28 ` Jann Horn [this message]
2020-10-17 23:14 ` [patch 15/40] mm/gup_benchmark: rename to mm/gup_test Andrew Morton
2020-10-17 23:14 ` [patch 16/40] selftests/vm: use a common gup_test.h Andrew Morton
2020-10-18 16:18 ` Linus Torvalds
2020-10-18 16:22 ` Linus Torvalds
2020-10-18 18:50 ` John Hubbard
2020-10-18 19:03 ` Matthew Wilcox
2020-10-18 19:12 ` John Hubbard
2020-10-18 19:33 ` Linus Torvalds
2020-10-18 19:48 ` John Hubbard
2020-10-20 4:13 ` John Hubbard
2020-10-20 16:45 ` Linus Torvalds
2020-10-20 18:45 ` John Hubbard
2020-10-17 23:14 ` [patch 17/40] selftests/vm: rename run_vmtests --> run_vmtests.sh Andrew Morton
2020-10-17 23:14 ` [patch 18/40] selftests/vm: minor cleanup: Makefile and gup_test.c Andrew Morton
2020-10-17 23:14 ` [patch 19/40] selftests/vm: only some gup_test items are really benchmarks Andrew Morton
2020-10-17 23:14 ` [patch 20/40] selftests/vm: gup_test: introduce the dump_pages() sub-test Andrew Morton
2020-10-17 23:14 ` [patch 21/40] selftests/vm: run_vmtests.sh: update and clean up gup_test invocation Andrew Morton
2020-10-17 23:14 ` [patch 22/40] selftests/vm: hmm-tests: remove the libhugetlbfs dependency Andrew Morton
2020-10-17 23:14 ` [patch 23/40] selftests/vm: 10x speedup for hmm-tests Andrew Morton
2020-10-17 23:14 ` [patch 24/40] mm/madvise: pass mm to do_madvise Andrew Morton
2020-10-17 23:14 ` [patch 25/40] pid: move pidfd_get_pid() to pid.c Andrew Morton
2020-10-17 23:14 ` [patch 26/40] mm/madvise: introduce process_madvise() syscall: an external memory hinting API Andrew Morton
2020-10-17 23:15 ` [patch 27/40] mm: update the documentation for vfree Andrew Morton
2020-10-17 23:15 ` [patch 28/40] mm: add a VM_MAP_PUT_PAGES flag for vmap Andrew Morton
2020-10-17 23:15 ` [patch 29/40] mm: add a vmap_pfn function Andrew Morton
2020-10-17 23:15 ` [patch 30/40] mm: allow a NULL fn callback in apply_to_page_range Andrew Morton
2020-10-17 23:15 ` [patch 31/40] zsmalloc: switch from alloc_vm_area to get_vm_area Andrew Morton
2020-10-17 23:15 ` [patch 32/40] drm/i915: use vmap in shmem_pin_map Andrew Morton
2020-10-17 23:15 ` [patch 33/40] drm/i915: stop using kmap in i915_gem_object_map Andrew Morton
2020-10-17 23:15 ` [patch 34/40] drm/i915: use vmap " Andrew Morton
2020-10-17 23:15 ` [patch 35/40] xen/xenbus: use apply_to_page_range directly in xenbus_map_ring_pv Andrew Morton
2020-10-17 23:15 ` [patch 36/40] x86/xen: open code alloc_vm_area in arch_gnttab_valloc Andrew Morton
2020-10-17 23:15 ` [patch 37/40] mm: remove alloc_vm_area Andrew Morton
2020-10-17 23:15 ` [patch 38/40] mm: cleanup the gfp_mask handling in __vmalloc_area_node Andrew Morton
2020-10-17 23:15 ` [patch 39/40] mm: remove the filename in the top of file comment in vmalloc.c Andrew Morton
2020-10-17 23:15 ` [patch 40/40] mm: remove duplicate include statement in mmu.c Andrew Morton
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