3.16.74-rc1 review patch. If anyone has any objections, please let me know.
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From: Dan Carpenter dan.carpenter@oracle.com
commit b586627e10f57ee3aa8f0cfab0d6f7dc4ae63760 upstream.
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: Ben Hutchings ben@decadent.org.uk --- kernel/debug/kdb/kdb_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -2569,7 +2569,7 @@ static int kdb_per_cpu(int argc, const c 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; }