Patch "MIPS: ptrace: Fix regs_return_value for kernel context" has been added to the 4.8-stable tree

Patch "MIPS: ptrace: Fix regs_return_value for kernel context" has been added to the 4.8-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    MIPS: ptrace: Fix regs_return_value for kernel context

to the 4.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mips-ptrace-fix-regs_return_value-for-kernel-context.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 74f1077b5b783e7bf4fa3007cefdc8dbd6c07518 Mon Sep 17 00:00:00 2001
From: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Date: Wed, 12 Oct 2016 09:32:56 +0200
Subject: MIPS: ptrace: Fix regs_return_value for kernel context

From: Marcin Nowakowski <marcin.nowakowski@imgtec.com>

commit 74f1077b5b783e7bf4fa3007cefdc8dbd6c07518 upstream.

Currently regs_return_value always negates reg[2] if it determines
the syscall has failed, but when called in kernel context this check is
invalid and may result in returning a wrong value.

This fixes errors reported by CONFIG_KPROBES_SANITY_TEST

Fixes: d7e7528bcd45 ("Audit: push audit success and retcode into arch ptrace.h")
Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14381/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/arch/mips/include/asm/ptrace.h
+++ b/arch/mips/include/asm/ptrace.h
@@ -152,7 +152,7 @@ static inline int is_syscall_success(str
 
 static inline long regs_return_value(struct pt_regs *regs)
 {
-	if (is_syscall_success(regs))
+	if (is_syscall_success(regs) || !user_mode(regs))
 		return regs->regs[2];
 	else
 		return -regs->regs[2];


Patches currently in stable-queue which might be from marcin.nowakowski@imgtec.com are

queue-4.8/mips-ptrace-fix-regs_return_value-for-kernel-context.patch