tree e4cdd0f7425df5050ed2a6a65c20334ced9576b1
parent 60de254403da20ed19024759a67afc2f12d8c072
author Axel Rasmussen <axelrasmussen@google.com> 1616446115 -0700
committer Tim Zimmermann <tim@linux4.de> 1721966659 +0200
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FROMLIST: userfaultfd/shmem: fix minor fault page leak

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@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>

Link: https://lore.kernel.org/patchwork/patch/1400686/
Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
Bug: 160737021
Bug: 169683130
Change-Id: I599f1434e24fce6e31d0d73c7f9c4714e9875b63