From: Dan Carpenter dan.carpenter@oracle.com
[ Upstream commit b586627e10f57ee3aa8f0cfab0d6f7dc4ae63760 ]
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@oracle.com Reviewed-by: Douglas Anderson dianders@chromium.org Signed-off-by: Daniel Thompson daniel.thompson@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 993db6b2348e7..15d902daeef6c 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -2634,7 +2634,7 @@ 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; }