[PATCH] alpha/kernel/traps: Use find_vma_intersection() in traps for setting si_code

From: Liam Howlett
Date: Thu Apr 01 2021 - 15:52:05 EST


find_vma() will continue to search upwards until the end of the virtual
memory space. This means the si_code would almost never be set to
SEGV_MAPERR even when the address falls outside of any VMA.

Using find_vma_intersection() allows for what is intended by only
returning a VMA if it falls within the range provided, in this case a
window of 1.

Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
arch/alpha/kernel/traps.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
index 921d4b6e4d95..7f51386c06d0 100644
--- a/arch/alpha/kernel/traps.c
+++ b/arch/alpha/kernel/traps.c
@@ -957,8 +957,10 @@ do_entUnaUser(void __user * va, unsigned long opcode,
si_code = SEGV_ACCERR;
else {
struct mm_struct *mm = current->mm;
+ unsigned long addr = (unsigned long)va;
+
mmap_read_lock(mm);
- if (find_vma(mm, (unsigned long)va))
+ if (find_vma_intersection(mm, addr, addr + 1))
si_code = SEGV_ACCERR;
else
si_code = SEGV_MAPERR;
--
2.30.0