The "whichcpu" comes from argv[3]. The cpu_online() macro looks up the
cpu in a bitmap of online cpus, but if the value is too high then it
could read beyond the end of the bitmap and possibly Oops.
Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
kernel/debug/kdb/kdb_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index fc96dbf8d9de..9ecfa37c7fbf 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -2583,7 +2583,7 @@ static int kdb_per_cpu(int argc, const char **argv)
diag = kdbgetularg(argv[3], &whichcpu);
if (diag)
return diag;
- if (!cpu_online(whichcpu)) {
+ if (whichcpu >= nr_cpu_ids || !cpu_online(whichcpu)) {
kdb_printf("cpu %ld is not online\n", whichcpu);
return KDB_BADCPUNUM;
}
--
2.18.0
