+ ia64-fix-ptraceptrace_syscall_info_exit-sign.patch added to -mm tree

+ ia64-fix-ptraceptrace_syscall_info_exit-sign.patch added to -mm tree

[akpm]

The patch titled
     Subject: ia64: fix ptrace(PTRACE_SYSCALL_INFO_EXIT) sign
has been added to the -mm tree.  Its filename is
     ia64-fix-ptraceptrace_syscall_info_exit-sign.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/ia64-fix-ptraceptrace_syscall_info_exit-sign.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/ia64-fix-ptraceptrace_syscall_info_exit-sign.patch

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------------------------------------------------------
From: Sergei Trofimovich <slyfox@gentoo.org>
Subject: ia64: fix ptrace(PTRACE_SYSCALL_INFO_EXIT) sign

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>
---

 arch/ia64/include/asm/syscall.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/ia64/include/asm/syscall.h~ia64-fix-ptraceptrace_syscall_info_exit-sign
+++ a/arch/ia64/include/asm/syscall.h
@@ -32,7 +32,7 @@ static inline void syscall_rollback(stru
 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,
_

Patches currently in -mm which might be from slyfox@gentoo.org are

ia64-fix-ia64_syscall_get_set_arguments-for-break-based-syscalls.patch
ia64-fix-ptraceptrace_syscall_info_exit-sign.patch