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author | Alexei Starovoitov <ast@kernel.org> | 2023-03-16 22:20:09 -0700 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2023-03-16 22:20:09 -0700 |
commit | 94bbbdfbde165820e4078ffe9a78305d556dec35 (patch) | |
tree | 72150b9a1f9a031ec812754ccf1712445093d951 | |
parent | 082cdc69a4651dd2a77539d69416a359ed1214f5 (diff) | |
parent | 5640b6d894342d153b719644681b0345fd28ee96 (diff) | |
download | bpf-94bbbdfbde165820e4078ffe9a78305d556dec35.tar.gz |
Merge branch 'double-fix bpf_test_run + XDP_PASS recycling'
Alexander Lobakin says:
====================
Enabling skb PP recycling revealed a couple issues in the bpf_test_run
code. Recycling broke the assumption that the headroom won't ever be
touched during the test_run execution: xdp_scrub_frame() invalidates the
XDP frame at the headroom start, while neigh xmit code overwrites 2 bytes
to the left of the Ethernet header. The first makes the kernel panic in
certain cases, while the second breaks xdp_do_redirect selftest on BE.
test_run is a limited-scope entity, so let's hope no more corner cases
will happen here or at least they will be as easy and pleasant to fix
as those two.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
-rw-r--r-- | net/bpf/test_run.c | 12 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c | 7 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/progs/test_xdp_do_redirect.c | 2 |
3 files changed, 16 insertions, 5 deletions
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 71226f68270d98..8d6b31209bd629 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -208,6 +208,16 @@ static void xdp_test_run_teardown(struct xdp_test_data *xdp) kfree(xdp->skbs); } +static bool frame_was_changed(const struct xdp_page_head *head) +{ + /* xdp_scrub_frame() zeroes the data pointer, flags is the last field, + * i.e. has the highest chances to be overwritten. If those two are + * untouched, it's most likely safe to skip the context reset. + */ + return head->frm.data != head->orig_ctx.data || + head->frm.flags != head->orig_ctx.flags; +} + static bool ctx_was_changed(struct xdp_page_head *head) { return head->orig_ctx.data != head->ctx.data || @@ -217,7 +227,7 @@ static bool ctx_was_changed(struct xdp_page_head *head) static void reset_ctx(struct xdp_page_head *head) { - if (likely(!ctx_was_changed(head))) + if (likely(!frame_was_changed(head) && !ctx_was_changed(head))) return; head->ctx.data = head->orig_ctx.data; diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c b/tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c index 856cbc29e6a1d2..4eaa3dcaebc834 100644 --- a/tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c +++ b/tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c @@ -86,12 +86,12 @@ static void test_max_pkt_size(int fd) void test_xdp_do_redirect(void) { int err, xdp_prog_fd, tc_prog_fd, ifindex_src, ifindex_dst; - char data[sizeof(pkt_udp) + sizeof(__u32)]; + char data[sizeof(pkt_udp) + sizeof(__u64)]; struct test_xdp_do_redirect *skel = NULL; struct nstoken *nstoken = NULL; struct bpf_link *link; LIBBPF_OPTS(bpf_xdp_query_opts, query_opts); - struct xdp_md ctx_in = { .data = sizeof(__u32), + struct xdp_md ctx_in = { .data = sizeof(__u64), .data_end = sizeof(data) }; DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts, .data_in = &data, @@ -105,8 +105,9 @@ void test_xdp_do_redirect(void) DECLARE_LIBBPF_OPTS(bpf_tc_hook, tc_hook, .attach_point = BPF_TC_INGRESS); - memcpy(&data[sizeof(__u32)], &pkt_udp, sizeof(pkt_udp)); + memcpy(&data[sizeof(__u64)], &pkt_udp, sizeof(pkt_udp)); *((__u32 *)data) = 0x42; /* metadata test value */ + *((__u32 *)data + 4) = 0; skel = test_xdp_do_redirect__open(); if (!ASSERT_OK_PTR(skel, "skel")) diff --git a/tools/testing/selftests/bpf/progs/test_xdp_do_redirect.c b/tools/testing/selftests/bpf/progs/test_xdp_do_redirect.c index cd2d4e3258b899..5baaafed0d2dec 100644 --- a/tools/testing/selftests/bpf/progs/test_xdp_do_redirect.c +++ b/tools/testing/selftests/bpf/progs/test_xdp_do_redirect.c @@ -52,7 +52,7 @@ int xdp_redirect(struct xdp_md *xdp) *payload = MARK_IN; - if (bpf_xdp_adjust_meta(xdp, 4)) + if (bpf_xdp_adjust_meta(xdp, sizeof(__u64))) return XDP_ABORTED; if (retcode > XDP_PASS) |