On Mon, Dec 11, 2023 at 3:27 AM Hou Tao <houtao@xxxxxxxxxxxxxxx> wrote:
>
> From: Hou Tao <houtao1@xxxxxxxxxx>
>
> An abnormally big cnt may be passed to link_create.uprobe_multi.cnt,
> and 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 using __GFP_NOWARN when invoking kvzalloc() in
> bpf_uprobe_multi_link_attach().
>
> Fixes: 89ae89f53d20 ("bpf: Add multi uprobe link")
> Reported-by: xingwei lee <xrivendell7@xxxxxxxxx>
> Closes: https://lore.kernel.org/bpf/CABOYnLwwJY=yFAGie59LFsUsBAgHfroVqbzZ5edAXbFE3YiNVA@xxxxxxxxxxxxxx
> Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
> ---
> kernel/trace/bpf_trace.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 774cf476a892..07b9b5896d6c 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -3378,7 +3378,7 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
> err = -ENOMEM;
>
> link = kzalloc(sizeof(*link), GFP_KERNEL);
> - uprobes = kvcalloc(cnt, sizeof(*uprobes), GFP_KERNEL);
> + uprobes = kvcalloc(cnt, sizeof(*uprobes), GFP_KERNEL | __GFP_NOWARN);
__GFP_NOWARN will hide actual malloc failures.
Let's limit cnt instead. Both for k and u multi probes.
