[PATCH v6 06/11] arm64: untag user address in __do_user_fault

Andrey Konovalov
2018-08-30T11:41:11Z

In __do_user_fault the fault address is being compared to TASK_SIZE to
find out whether the address lies in the kernel or in user space. Since
the fault address is coming from a user it can be tagged.

Untag the pointer before comparing.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
arch/arm64/mm/fault.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 50b30ff30de4..871fb3c38b23 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -313,7 +313,7 @@ static void __do_user_fault(struct siginfo *info, unsigned int esr)
* type", so we ignore this wrinkle and just return the translation
* fault.)
*/
- if (current->thread.fault_address >= TASK_SIZE) {
+ if (untagged_addr(current->thread.fault_address) >= TASK_SIZE) {
switch (ESR_ELx_EC(esr)) {
case ESR_ELx_EC_DABT_LOW:
/*
--
2.19.0.rc0.228.g281dcd1b4d0-goog