4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
commit 4920e3cf77347d7d7373552d4839e8d832321313 upstream.
The current implementation of setup_randomness uses the stack address
and therefore the pointer to the SYSIB 3.2.2 block as input data
address. Furthermore the length of the input data is the number of
virtual-machine description blocks which is typically one.
This means that typically a single zero byte is fed to
add_device_randomness.
Fix both of these and use the address of the first virtual machine
description block as input data address and also use the correct
length.
Fixes: bcfcbb6bae64 ("s390: add system information as device randomness")
Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/kernel/setup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -807,7 +807,7 @@ static void __init setup_randomness(void
vmms = (struct sysinfo_3_2_2 *) memblock_alloc(PAGE_SIZE, PAGE_SIZE);
if (stsi(vmms, 3, 2, 2) == 0 && vmms->count)
- add_device_randomness(&vmms, vmms->count);
+ add_device_randomness(&vmms->vm, sizeof(vmms->vm[0]) * vmms->count);
memblock_free((unsigned long) vmms, PAGE_SIZE);
}