[PATCH] sparc64: fix adjtimex regression

From: Arnd Bergmann
Date: Sat Feb 01 2020 - 16:22:05 EST


Anatoly Pugachev reported one of the y2038 patches to introduce
a fatal bug from a stupid typo:

[ 96.384129] watchdog: BUG: soft lockup - CPU#8 stuck for 22s!
...
[ 96.385624] [0000000000652ca4] handle_mm_fault+0x84/0x320
[ 96.385668] [0000000000b6f2bc] do_sparc64_fault+0x43c/0x820
[ 96.385720] [0000000000407754] sparc64_realfault_common+0x10/0x20
[ 96.385769] [000000000042fa28] __do_sys_sparc_clock_adjtime+0x28/0x80
[ 96.385819] [00000000004307f0] sys_sparc_clock_adjtime+0x10/0x20
[ 96.385866] [0000000000406294] linux_sparc_syscall+0x34/0x44

Fix the code to dereference the correct pointer again.

Reported-by: Anatoly Pugachev <matorola@xxxxxxxxx>
Tested-by: Anatoly Pugachev <matorola@xxxxxxxxx>
Fixes: 251ec1c159e4 ("y2038: sparc: remove use of struct timex")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
The bug was introduced through my y2038 branch and is now in
mainline, but not in v5.5. Who should pick up the fix to
get it into v5.6-rc1?
---
arch/sparc/kernel/sys_sparc_64.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index 34917617f258..6b92fadb6ec7 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -551,7 +551,7 @@ SYSCALL_DEFINE2(getdomainname, char __user *, name, int, len)
SYSCALL_DEFINE1(sparc_adjtimex, struct __kernel_timex __user *, txc_p)
{
struct __kernel_timex txc;
- struct __kernel_old_timeval *tv = (void *)&txc_p->time;
+ struct __kernel_old_timeval *tv = (void *)&txc.time;
int ret;

/* Copy the user data space into the kernel copy
@@ -576,7 +576,7 @@ SYSCALL_DEFINE2(sparc_clock_adjtime, const clockid_t, which_clock,
struct __kernel_timex __user *, txc_p)
{
struct __kernel_timex txc;
- struct __kernel_old_timeval *tv = (void *)&txc_p->time;
+ struct __kernel_old_timeval *tv = (void *)&txc.time;
int ret;

if (!IS_ENABLED(CONFIG_POSIX_TIMERS)) {
--
2.25.0