[PATCH v2 3/3] riscv: Fix crash when flushing executable ioremap regions

[Jan Kiszka]

From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>

Those are not backed by page structs, and pte_page is returning an
invalid pointer.

Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
---
 arch/riscv/mm/cacheflush.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
index 8930ab7278e6..9ee2c1a387cc 100644
--- a/arch/riscv/mm/cacheflush.c
+++ b/arch/riscv/mm/cacheflush.c
@@ -84,7 +84,8 @@ void flush_icache_pte(pte_t pte)
 {
 	struct page *page = pte_page(pte);

-	if (!test_and_set_bit(PG_dcache_clean, &page->flags))
+	if (!pfn_valid(pte_pfn(pte)) ||
+	    !test_and_set_bit(PG_dcache_clean, &page->flags))
 		flush_icache_all();
 }
 #endif /* CONFIG_MMU */
--
2.16.4