From: Alexander Gordeev <agordeev@linux.ibm.com>
Date: Fri, 15 Jul 2022 10:59:33 +0000 (+0200)
Subject: s390/crash: fix incorrect number of bytes to copy to user space
X-Git-Tag: v5.18.18~199
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f7b4d4720838020725f06c6b45d69f23bb646d13;p=thirdparty%2Fkernel%2Fstable.git

s390/crash: fix incorrect number of bytes to copy to user space

[ Upstream commit f6749da17a34eb08c9665f072ce7c812ff68aad2 ]

The number of bytes in a chunk is correctly calculated, but instead
the total number of bytes is passed to copy_to_user_real() function.

Reported-by: Matthew Wilcox <willy@infradead.org>
Fixes: df9694c7975f ("s390/dump: streamline oldmem copy functions")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index 28124d0fa1d5e..f8ebdd70dd317 100644
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -199,7 +199,7 @@ static int copy_oldmem_user(void __user *dst, unsigned long src, size_t count)
 			} else {
 				len = count;
 			}
-			rc = copy_to_user_real(dst, src, count);
+			rc = copy_to_user_real(dst, src, len);
 			if (rc)
 				return rc;
 		}