diff options
author | Michael S. Tsirkin <[email protected]> | 2018-04-13 15:35:16 -0700 |
---|---|---|
committer | Linus Torvalds <[email protected]> | 2018-04-13 17:10:27 -0700 |
commit | 09e35a4a1ca8b9988ca9b8557d17948cd6c0808b (patch) | |
tree | db4f2d25cac5066841c03f8e1cebdb55898d03df | |
parent | 60bb83b81169820c691fbfa33a6a4aef32aa4b0b (diff) |
mm/gup_benchmark: handle gup failures
Patch series "mm/get_user_pages_fast fixes, cleanups", v2.
Turns out get_user_pages_fast and __get_user_pages_fast return different
values on error when given a single page: __get_user_pages_fast returns
0. get_user_pages_fast returns either 0 or an error.
Callers of get_user_pages_fast expect an error so fix it up to return an
error consistently.
Stress the difference between get_user_pages_fast and
__get_user_pages_fast to make sure callers aren't confused.
This patch (of 3):
__gup_benchmark_ioctl does not handle the case where get_user_pages_fast
fails:
- a negative return code will cause a buffer overrun
- returning with partial success will cause use of uninitialized
memory.
[[email protected]: simplification]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Huang Ying <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Thorsten Leemhuis <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
-rw-r--r-- | mm/gup_benchmark.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c index 5c8e2abeaa15..0f44759486e2 100644 --- a/mm/gup_benchmark.c +++ b/mm/gup_benchmark.c @@ -23,7 +23,7 @@ static int __gup_benchmark_ioctl(unsigned int cmd, struct page **pages; nr_pages = gup->size / PAGE_SIZE; - pages = kvmalloc(sizeof(void *) * nr_pages, GFP_KERNEL); + pages = kvzalloc(sizeof(void *) * nr_pages, GFP_KERNEL); if (!pages) return -ENOMEM; @@ -41,6 +41,8 @@ static int __gup_benchmark_ioctl(unsigned int cmd, } nr = get_user_pages_fast(addr, nr, gup->flags & 1, pages + i); + if (nr <= 0) + break; i += nr; } end_time = ktime_get(); |