From: Ian Rogers irogers@google.com
[ Upstream commit af515a5587b8f45f19e11657746e0c89411b0380 ]
The put lowers the reference count to 0 and frees ctx, reading it afterwards is invalid. Move the put after the uses and determine the last use by the reference count being 1.
Fixes: 39e940d4abfa ("selftests/xsk: Destroy BPF resources only when ctx refcount drops to 0") Signed-off-by: Ian Rogers irogers@google.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Magnus Karlsson magnus.karlsson@intel.com Link: https://lore.kernel.org/bpf/20220901202645.1463552-1-irogers@google.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/xsk.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 67dc010e9fe3..63954a2e213d 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -1228,15 +1228,15 @@ void xsk_socket__delete(struct xsk_socket *xsk) ctx = xsk->ctx; umem = ctx->umem;
- xsk_put_ctx(ctx, true); - - if (!ctx->refcount) { + if (ctx->refcount == 1) { xsk_delete_bpf_maps(xsk); close(ctx->prog_fd); if (ctx->has_bpf_link) close(ctx->link_fd); }
+ xsk_put_ctx(ctx, true); + err = xsk_get_mmap_offsets(xsk->fd, &off); if (!err) { if (xsk->rx) {