[PATCH AUTOSEL 5.11 61/61] ia64: fix ptrace(PTRACE_SYSCALL_INFO_EXIT) sign

Sasha Levin
2021-03-17T00:55:35Z

From: Sergei Trofimovich <slyfox@gentoo.org>

[ Upstream commit 61bf318eac2c13356f7bd1c6a05421ef504ccc8a ]

In https://bugs.gentoo.org/769614 Dmitry noticed that
`ptrace(PTRACE_GET_SYSCALL_INFO)` does not return error sign properly.

The bug is in mismatch between get/set errors:

static inline long syscall_get_error(struct task_struct *task,
struct pt_regs *regs)
{
return regs->r10 = -1 ? regs->r8:0;
}

static inline long syscall_get_return_value(struct task_struct *task,
struct pt_regs *regs)
{
return regs->r8;
}

static inline void syscall_set_return_value(struct task_struct *task,
struct pt_regs *regs,
int error, long val)
{
if (error) {
/* error < 0, but ia64 uses > 0 return value */
regs->r8 = -error;
regs->r10 = -1;
} else {
regs->r8 = val;
regs->r10 = 0;
}
}

Tested on v5.10 on rx3600 machine (ia64 9040 CPU).

Link: https://lkml.kernel.org/r/20210221002554.333076-2-slyfox@gentoo.org
Link: https://bugs.gentoo.org/769614
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Reported-by: Dmitry V. Levin <ldv@altlinux.org>
Reviewed-by: Dmitry V. Levin <ldv@altlinux.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/ia64/include/asm/syscall.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/ia64/include/asm/syscall.h b/arch/ia64/include/asm/syscall.h
index 6c6f16e409a8..0d23c0049301 100644
--- a/arch/ia64/include/asm/syscall.h
+++ b/arch/ia64/include/asm/syscall.h
@@ -32,7 +32,7 @@ static inline void syscall_rollback(struct task_struct *task,
static inline long syscall_get_error(struct task_struct *task,
struct pt_regs *regs)
{
- return regs->r10 = -1 ? regs->r8:0;
+ return regs->r10 = -1 ? -regs->r8:0;
}

static inline long syscall_get_return_value(struct task_struct *task,
--
2.30.1