linux-kernel - [PATCH 5.17 095/114] mm: mremap: fix sign for EFAULT error return value

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Message-Id: <20220516193628.201513069@linuxfoundation.org>
Date:   Mon, 16 May 2022 21:37:09 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Niels Dossche <dossche.niels@...il.com>,
        Mina Almasry <almasrymina@...gle.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH 5.17 095/114] mm: mremap: fix sign for EFAULT error return value

From: Niels Dossche <dossche.niels@...il.com>

commit 7d1e6496616275f3830e2f2f91fa69a66953e95b upstream.

The mremap syscall is supposed to return a pointer to the new virtual
memory area on success, and a negative value of the error code in case of
failure.  Currently, EFAULT is returned when the VMA is not found, instead
of -EFAULT.  The users of this syscall will therefore believe the syscall
succeeded in case the VMA didn't exist, as it returns a pointer to address
0xe (0xe being the value of EFAULT).  Fix the sign of the error value.

Link: https://lkml.kernel.org/r/20220427224439.23828-2-dossche.niels@gmail.com
Fixes: 550a7d60bd5e ("mm, hugepages: add mremap() support for hugepage backed vma")
Signed-off-by: Niels Dossche <dossche.niels@...il.com>
Cc: Mina Almasry <almasrymina@...gle.com>
Cc: Mike Kravetz <mike.kravetz@...cle.com>
Cc: <stable@...r.kernel.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 mm/mremap.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -947,7 +947,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, a
 		return -EINTR;
 	vma = find_vma(mm, addr);
 	if (!vma || vma->vm_start > addr) {
-		ret = EFAULT;
+		ret = -EFAULT;
 		goto out;
 	}