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| author |   Luigi Rizzo <lrizzo@google.com> | 2021-09-02 14:56:46 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2021-09-03 09:58:13 -0700 |
| commit | 5b78ed24e8ec48602c1d6f5a188e58d000c81e2b (patch) | |
| tree | fb2e4dea2199850c8ab0ca7492acab96a06a15a0 /fs/exec.c | |
| parent | mm: change fault_in_pages_* to have an unsigned size parameter (diff) | |
| download | linux-dev-5b78ed24e8ec48602c1d6f5a188e58d000c81e2b.tar.xz linux-dev-5b78ed24e8ec48602c1d6f5a188e58d000c81e2b.zip | |
mm/pagemap: add mmap_assert_locked() annotations to find_vma*()
find_vma() and variants need protection when used. This patch adds
mmap_assert_lock() calls in the functions.
To make sure the invariant is satisfied, we also need to add a
mmap_read_lock() around the get_user_pages_remote() call in
get_arg_page(). The lock is not strictly necessary because the mm has
been newly created, but the extra cost is limited because the same mutex
was also acquired shortly before in __bprm_mm_init(), so it is hot and
uncontended.
[penguin-kernel@i-love.sakura.ne.jp: TOMOYO needs the same protection which get_arg_page() needs]
Link: https://lkml.kernel.org/r/58bb6bf7-a57e-8a40-e74b-39584b415152@i-love.sakura.ne.jp
Link: https://lkml.kernel.org/r/20210731175341.3458608-1-lrizzo@google.com
Signed-off-by: Luigi Rizzo <lrizzo@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/exec.c')
| -rw-r--r-- | fs/exec.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/exec.c b/fs/exec.c index 41a888d4edde..fd292e9da4f9 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -217,8 +217,10 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, * We are doing an exec(). 'current' is the process * doing the exec and bprm->mm is the new process's mm. */ + mmap_read_lock(bprm->mm); ret = get_user_pages_remote(bprm->mm, pos, 1, gup_flags, &page, NULL, NULL); + mmap_read_unlock(bprm->mm); if (ret <= 0) return NULL; |