Re: [PATCH] userfaultfd/shmem: fix minor fault page leak

[Peter Xu]

On Mon, Mar 22, 2021 at 01:48:35PM -0700, Axel Rasmussen wrote:
> This fix is analogous to Peter Xu's fix for hugetlb [0]. If we don't
> put_page() after getting the page out of the page cache, we leak the
> reference.
> 
> The fix can be verified by checking /proc/meminfo and running the
> userfaultfd selftest in shmem mode. Without the fix, we see MemFree /
> MemAvailable steadily decreasing with each run of the test. With the
> fix, memory is correctly freed after the test program exits.
> 
> Fixes: 00da60b9d0a0 ("userfaultfd: support minor fault handling for shmem")
> Signed-off-by: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>

Reviewed-by: Peter Xu <peterx@xxxxxxxxxx>

-- 
Peter Xu