[PATCH 1/2] mm: mremap: fix sign for EFAULT error return value

From: Niels Dossche
Date: Wed Apr 27 2022 - 18:46:43 EST


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.

Fixes: 550a7d60bd5e ("mm, hugepages: add mremap() support for hugepage backed vma")
Signed-off-by: Niels Dossche <dossche.niels@xxxxxxxxx>
---
mm/mremap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/mremap.c b/mm/mremap.c
index 303d3290b938..0b93fac76851 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -947,7 +947,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
return -EINTR;
vma = vma_lookup(mm, addr);
if (!vma) {
- ret = EFAULT;
+ ret = -EFAULT;
goto out;
}

--
2.35.2