From: He Zhe <zhe.he@xxxxxxxxxxxxx>
debug_guardpage_minorder_setup and cmdline_parse_kernelcore do not check
input argument before using it. The argument would be a NULL pointer if
"debug_guardpage_minorder" or "kernelcore", without its value, is set in
command line and thus causes the following panic.
PANIC: early exception 0xe3 IP 10:ffffffffa08146f1 error 0 cr2 0x0
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc4-yocto-standard+ #1
[ 0.000000] RIP: 0010:parse_option_str+0x11/0x90
...
[ 0.000000] Call Trace:
[ 0.000000] cmdline_parse_kernelcore+0x19/0x41
[ 0.000000] do_early_param+0x57/0x8e
[ 0.000000] parse_args+0x208/0x320
[ 0.000000] ? rdinit_setup+0x30/0x30
[ 0.000000] parse_early_options+0x29/0x2d
[ 0.000000] ? rdinit_setup+0x30/0x30
[ 0.000000] parse_early_param+0x36/0x4d
[ 0.000000] setup_arch+0x336/0x99e
[ 0.000000] start_kernel+0x6f/0x4ee
[ 0.000000] x86_64_start_reservations+0x24/0x26
[ 0.000000] x86_64_start_kernel+0x6f/0x72
[ 0.000000] secondary_startup_64+0xa4/0xb0
This patch adds a check to prevent the panic and adds KBUILD_MODNAME to
prints.
Signed-off-by: He Zhe <zhe.he@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Cc: akpm@xxxxxxxxxxxxxxxxxxxx
Cc: mhocko@xxxxxxxx
Cc: vbabka@xxxxxxx
Cc: pasha.tatashin@xxxxxxxxxx
Cc: mgorman@xxxxxxxxxxxxxxxxxxx
Cc: aaron.lu@xxxxxxxxx
Cc: osalvador@xxxxxxx
Cc: iamjoonsoo.kim@xxxxxxx
---
mm/page_alloc.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 89d2a2a..d4cda06 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -14,6 +14,8 @@
* (lots of bits borrowed from Ingo Molnar & Andrew Morton)
*/
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
#include <linux/stddef.h>
#include <linux/mm.h>
#include <linux/swap.h>
@@ -630,6 +632,11 @@ static int __init debug_guardpage_minorder_setup(char *buf)
{
unsigned long res;
+ if (!buf) {
+ pr_err("Config string not provided\n");
+ return -EINVAL;
+ }
+
if (kstrtoul(buf, 10, &res) < 0 || res > MAX_ORDER / 2) {
pr_err("Bad debug_guardpage_minorder value\n");
return 0;
@@ -6952,6 +6959,11 @@ static int __init cmdline_parse_core(char *p, unsigned long *core,
*/
static int __init cmdline_parse_kernelcore(char *p)
{
+ if (!p) {
+ pr_err("Config string not provided\n");
+ return -EINVAL;
+ }
+
/* parse kernelcore=mirror */
if (parse_option_str(p, "mirror")) {
mirrored_kernelcore = true;
--
2.7.4
