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| author | Michael S. Tsirkin <mst@redhat.com> | 2018-04-14 01:35:16 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-14 03:10:27 +0300 |
| commit | 09e35a4a1ca8b9988ca9b8557d17948cd6c0808b (patch) | |
| tree | db4f2d25cac5066841c03f8e1cebdb55898d03df | |
| parent | 60bb83b81169820c691fbfa33a6a4aef32aa4b0b (diff) | |
| download | linux-09e35a4a1ca8b9988ca9b8557d17948cd6c0808b.tar.xz | |
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.
[akpm@linux-foundation.org: simplification]
Link: http://lkml.kernel.org/r/1522962072-182137-3-git-send-email-mst@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -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(); |