On Mon, May 06, 2019 at 03:50:18PM +0300, Dan Carpenter wrote:
> 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>
Just out of interest... why isn't this copied to LKML? Omiting LKML makes
the patch hard to find in a patchwork instance.
Daniel.
> ---
> 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
>
