Messages in this thread Patch in this message |  | | Date | Fri, 6 Apr 2018 00:03:49 +0300 | From | "Michael S. Tsirkin" <> | Subject | [PATCH v2 1/3] mm/gup_benchmark: handle gup failures |
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__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.
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> 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: Michael S. Tsirkin <mst@redhat.com> --- mm/gup_benchmark.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c index 5c8e2ab..d743035 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; @@ -41,7 +41,8 @@ static int __gup_benchmark_ioctl(unsigned int cmd, } nr = get_user_pages_fast(addr, nr, gup->flags & 1, pages + i); - i += nr; + if (nr > 0) + i += nr; } end_time = ktime_get(); -- MST
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