mm/khugepaged: fix invalid page access in release_pte_pages()

release_pte_pages() converts from a pfn to a folio by using pfn_folio(). 
If the pte is not mapped, pfn_folio() will result in undefined behavior
which ends up causing a kernel panic[1].

Only call pfn_folio() once we have validated that the pte is both valid
and mapped to fix the issue.

[1] https://lore.kernel.org/linux-mm/[email protected]/

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Vishal Moola (Oracle) <[email protected]>
Fixes: 9bdfeea46f49 ("mm/khugepaged: convert release_pte_pages() to use folios")
Reported-by: Marek Szyprowski <[email protected]>
Tested-by: Marek Szyprowski <[email protected]>
Debugged-by: Alexandre Ghiti <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions