6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Huacai Chen <chenhuacai@xxxxxxxxxxx>
commit 639420e9f6cd9ca074732b17ac450d2518d5937f upstream.
The earlycon parameter is based on fixmap, and fixmap addresses are not
supposed to be shadowed by KASAN. So return the kasan_early_shadow_page
in kasan_mem_to_shadow() if the input address is above FIXADDR_START.
Otherwise earlycon cannot work after kasan_init().
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 5aa4ac64e6add3e ("LoongArch: Add KASAN (Kernel Address Sanitizer) support")
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/loongarch/mm/kasan_init.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/loongarch/mm/kasan_init.c b/arch/loongarch/mm/kasan_init.c
index cc3e81fe0186..c608adc99845 100644
--- a/arch/loongarch/mm/kasan_init.c
+++ b/arch/loongarch/mm/kasan_init.c
@@ -44,6 +44,9 @@ void *kasan_mem_to_shadow(const void *addr)
unsigned long xrange = (maddr >> XRANGE_SHIFT) & 0xffff;
unsigned long offset = 0;
+ if (maddr >= FIXADDR_START)
+ return (void *)(kasan_early_shadow_page);
+
maddr &= XRANGE_SHADOW_MASK;
switch (xrange) {
case XKPRANGE_CC_SEG:
--
2.43.2
