> On Jan 15, 2019, at 2:54 PM, Stanislav Fomichev <s...@google.com> wrote:
>
> When returning BPF_STACK_BUILD_ID_IP from stack_map_get_build_id_offset,
> make sure that build_id field is empty. Since we are using percpu
> free list, there is a possibility that we might reuse some previous
> bpf_stack_build_id with non-zero build_id.
>
> Fixes: 615755a77b24 ("bpf: extend stackmap to save binary_build_id+offset
> instead of address")
> Signed-off-by: Stanislav Fomichev <s...@google.com>
Acked-by: Song Liu <songliubrav...@fb.com>
> ---
> kernel/bpf/stackmap.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
> index 8975d1768dcb..f4b57c68c45f 100644
> --- a/kernel/bpf/stackmap.c
> +++ b/kernel/bpf/stackmap.c
> @@ -315,6 +315,7 @@ static void stack_map_get_build_id_offset(struct
> bpf_stack_build_id *id_offs,
> for (i = 0; i < trace_nr; i++) {
> id_offs[i].status = BPF_STACK_BUILD_ID_IP;
> id_offs[i].ip = ips[i];
> + memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE);
> }
> return;
> }
> @@ -325,6 +326,7 @@ static void stack_map_get_build_id_offset(struct
> bpf_stack_build_id *id_offs,
> /* per entry fall back to ips */
> id_offs[i].status = BPF_STACK_BUILD_ID_IP;
> id_offs[i].ip = ips[i];
> + memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE);
> continue;
> }
> id_offs[i].offset = (vma->vm_pgoff << PAGE_SHIFT) + ips[i]
> --
> 2.20.1.97.g81188d93c3-goog
>
