bpf: Limit the number of kprobes when attaching program to multiple kprobes

An abnormally big cnt may also be assigned to kprobe_multi.cnt when
attaching multiple kprobes. It will trigger the following warning in
kvmalloc_node():

	if (unlikely(size > INT_MAX)) {
	    WARN_ON_ONCE(!(flags & __GFP_NOWARN));
	    return NULL;
	}

Fix the warning by limiting the maximal number of kprobes in
bpf_kprobe_multi_link_attach(). If the number of kprobes is greater than
MAX_KPROBE_MULTI_CNT, the attachment will fail and return -E2BIG.

Fixes: 0dcac2725406 ("bpf: Add multi kprobe link")
Signed-off-by: Hou Tao <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

0 files changed, 0 insertions, 0 deletions