mm/damon/paddr: fix folio_size() call after folio_put() in damon_pa_young()

Patch series "mm/damon/paddr: Fix folio-use-after-put bugs".

There are two folio accesses after folio_put() in mm/damon/paddr.c file.
Fix those.

This patch (of 2):

damon_pa_young() is accessing a folio via folio_size() after folio_put()
for the folio has invoked.  Fix it.

Link: https://lkml.kernel.org/r/20230304193949.296391-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20230304193949.296391-2-sj@kernel.org
Fixes: 397b0c3a584b ("mm/damon/paddr: remove folio_sz field from damon_pa_access_chk_result")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: <stable@vger.kernel.org>	[6.2.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index 6c655d9..49b267b 100644 (file)
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -130,7 +130,6 @@ static bool damon_pa_young(unsigned long paddr, unsigned long *folio_sz)
                        accessed = false;
                else
                        accessed = true;
-               folio_put(folio);
                goto out;
        }
 
@@ -144,10 +143,10 @@ static bool damon_pa_young(unsigned long paddr, unsigned long *folio_sz)
 
        if (need_lock)
                folio_unlock(folio);
-       folio_put(folio);
 
 out:
        *folio_sz = folio_size(folio);
+       folio_put(folio);
        return accessed;
 }