Merge branch 'bpf-xdp-offload-fixes'

Toke Høiland-Jørgensen says:

====================
This series restores the test_offload.py selftest to working order. It seems a
number of subtle behavioural changes have crept into various subsystems which
broke test_offload.py in a number of ways. Most of these are fairly benign
changes where small adjustments to the test script seems to be the best fix,
but one is an actual kernel bug that I've observed in the wild caused by a bad
interaction between xdp_attachment_flags_ok() and the rework of XDP program
handling in the core netdev code.

Patch 1 fixes the bug by removing xdp_attachment_flags_ok(), and the reminder of
the patches are adjustments to test_offload.py, including a new feature for
netdevsim to force a BPF verification fail. Please see the individual patches
for details.

Changelog:

v4:
  - Accidentally truncated the Fixes: hashes in patches 3/4 to 11 chars
v3:
  - Add Fixes: tags
v2:
  - Replace xdp_attachment_flags_ok() with a check in dev_xdp_attach()
  - Better packing of struct nsim_dev
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 29 insertions, 24 deletions

diff --git a/tools/testing/selftests/bpf/test_offload.py b/tools/testing/selftests/bpf/test_offload.py
index 43c9cda199b8..b99bb8ed3ed4 100755
--- a/tools/testing/selftests/bpf/test_offload.py
+++ b/tools/testing/selftests/bpf/test_offload.py
@@ -184,9 +184,7 @@ def bpftool_prog_list(expected=None, ns=""):
 def bpftool_map_list(expected=None, ns=""):
     _, maps = bpftool("map show", JSON=True, ns=ns, fail=True)
     # Remove the base maps
-    for m in base_maps:
-        if m in maps:
-            maps.remove(m)
+    maps = [m for m in maps if m not in base_maps and m.get('name') not in base_map_names]
     if expected is not None:
         if len(maps) != expected:
             fail(True, "%d BPF maps loaded, expected %d" %
@@ -716,13 +714,11 @@ def test_multi_prog(simdev, sim, obj, modename, modeid):
     fail(ret == 0, "Replaced one of programs without -force")
     check_extack(err, "XDP program already attached.", args)
 
-    if modename == "" or modename == "drv":
-        othermode = "" if modename == "drv" else "drv"
-        start_test("Test multi-attachment XDP - detach...")
-        ret, _, err = sim.unset_xdp(othermode, force=True,
-                                    fail=False, include_stderr=True)
-        fail(ret == 0, "Removed program with a bad mode")
-        check_extack(err, "program loaded with different flags.", args)
+    start_test("Test multi-attachment XDP - remove without mode...")
+    ret, _, err = sim.unset_xdp("", force=True,
+                                fail=False, include_stderr=True)
+    fail(ret == 0, "Removed program without a mode flag")
+    check_extack(err, "More than one program loaded, unset mode is ambiguous.", args)
 
     sim.unset_xdp("offload")
     xdp = sim.ip_link_show(xdp=True)["xdp"]
@@ -772,6 +768,9 @@ ret, progs = bpftool("prog", fail=False)
 skip(ret != 0, "bpftool not installed")
 base_progs = progs
 _, base_maps = bpftool("map")
+base_map_names = [
+    'pid_iter.rodata' # created on each bpftool invocation
+]
 
 # Check netdevsim
 ret, out = cmd("modprobe netdevsim", fail=False)
@@ -913,11 +912,18 @@ try:
 
     sim.tc_flush_filters()
 
+    start_test("Test TC offloads failure...")
+    sim.dfs["dev/bpf_bind_verifier_accept"] = 0
+    ret, _, err = sim.cls_bpf_add_filter(obj, verbose=True, skip_sw=True,
+                                         fail=False, include_stderr=True)
+    fail(ret == 0, "TC filter did not reject with TC offloads enabled")
+    check_verifier_log(err, "[netdevsim] Hello from netdevsim!")
+    sim.dfs["dev/bpf_bind_verifier_accept"] = 1
+
     start_test("Test TC offloads work...")
     ret, _, err = sim.cls_bpf_add_filter(obj, verbose=True, skip_sw=True,
                                          fail=False, include_stderr=True)
     fail(ret != 0, "TC filter did not load with TC offloads enabled")
-    check_verifier_log(err, "[netdevsim] Hello from netdevsim!")
 
     start_test("Test TC offload basics...")
     dfs = simdev.dfs_get_bound_progs(expected=1)
@@ -941,6 +947,7 @@ try:
     start_test("Test disabling TC offloads is rejected while filters installed...")
     ret, _ = sim.set_ethtool_tc_offloads(False, fail=False)
     fail(ret == 0, "Driver should refuse to disable TC offloads with filters installed...")
+    sim.set_ethtool_tc_offloads(True)
 
     start_test("Test qdisc removal frees things...")
     sim.tc_flush_filters()
@@ -999,18 +1006,8 @@ try:
                               fail=False, include_stderr=True)
     fail(ret == 0, "Replaced XDP program with a program in different mode")
     check_extack(err,
-                 "native and generic XDP can't be active at the same time.",
+                 "Native and generic XDP can't be active at the same time.",
                  args)
-    ret, _, err = sim.set_xdp(obj, "", force=True,
-                              fail=False, include_stderr=True)
-    fail(ret == 0, "Replaced XDP program with a program in different mode")
-    check_extack(err, "program loaded with different flags.", args)
-
-    start_test("Test XDP prog remove with bad flags...")
-    ret, _, err = sim.unset_xdp("", force=True,
-                                fail=False, include_stderr=True)
-    fail(ret == 0, "Removed program with a bad mode")
-    check_extack(err, "program loaded with different flags.", args)
 
     start_test("Test MTU restrictions...")
     ret, _ = sim.set_mtu(9000, fail=False)
@@ -1040,10 +1037,19 @@ try:
     offload = bpf_pinned("/sys/fs/bpf/offload")
     ret, _, err = sim.set_xdp(offload, "drv", fail=False, include_stderr=True)
     fail(ret == 0, "attached offloaded XDP program to drv")
-    check_extack(err, "using device-bound program without HW_MODE flag is not supported.", args)
+    check_extack(err, "Using device-bound program without HW_MODE flag is not supported.", args)
     rm("/sys/fs/bpf/offload")
     sim.wait_for_flush()
 
+    start_test("Test XDP load failure...")
+    sim.dfs["dev/bpf_bind_verifier_accept"] = 0
+    ret, _, err = bpftool_prog_load("sample_ret0.o", "/sys/fs/bpf/offload",
+                                 dev=sim['ifname'], fail=False, include_stderr=True)
+    fail(ret == 0, "verifier should fail on load")
+    check_verifier_log(err, "[netdevsim] Hello from netdevsim!")
+    sim.dfs["dev/bpf_bind_verifier_accept"] = 1
+    sim.wait_for_flush()
+
     start_test("Test XDP offload...")
     _, _, err = sim.set_xdp(obj, "offload", verbose=True, include_stderr=True)
     ipl = sim.ip_link_show(xdp=True)
@@ -1051,7 +1057,6 @@ try:
     progs = bpftool_prog_list(expected=1)
     prog = progs[0]
     fail(link_xdp["id"] != prog["id"], "Loaded program has wrong ID")
-    check_verifier_log(err, "[netdevsim] Hello from netdevsim!")
 
     start_test("Test XDP offload is device bound...")
     dfs = simdev.dfs_get_bound_progs(expected=1)