printk: return -EINVAL if the message len is bigger than the buf size
printk: return -EINVAL if the message len is bigger than the buf size

Just like what devkmsg_read() does, return -EINVAL if the message len is
bigger than the buf size, or it will trigger a segfault error.

Acked-by: Kay Sievers <e9264147b413746293e539868c8edff71715e1e3@vrfy.org>
Acked-by: Fengguang Wu <f25caf39e3e90f2a28a0f6211af92081109b663e@linux.intel.com>
Signed-off-by: Yuanhan Liu <5dcef21195e64c9c08aa779bb62b25e9133eaa33@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs