linux-stable.git/tools/testing/selftests/bpf, branch v5.4.78

bpf: Zero-fill re-used per-cpu map element

2020-11-18T18:20:26+00:00

[ Upstream commit d3bec0138bfbe58606fc1d6f57a4cdc1a20218db ]

Zero-fill element values for all other cpus than current, just as
when not using prealloc. This is the only way the bpf program can
ensure known initial values for all cpus ('onallcpus' cannot be
set when coming from the bpf program).

The scenario is: bpf program inserts some elements in a per-cpu
map, then deletes some (or userspace does). When later adding
new elements using bpf_map_update_elem(), the bpf program can
only set the value of the new elements for the current cpu.
When prealloc is enabled, previously deleted elements are re-used.
Without the fix, values for other cpus remain whatever they were
when the re-used entry was previously freed.

A selftest is added to validate correct operation in above
scenario as well as in case of LRU per-cpu map element re-use.

Fixes: 6c9059817432 ("bpf: pre-allocate hash map elements")
Signed-off-by: David Verbeiren 
Signed-off-by: Alexei Starovoitov 
Acked-by: Matthieu Baerts 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20201104112332.15191-1-david.verbeiren@tessares.net
Signed-off-by: Sasha Levin

selftests/bpf: Define string const as global for test_sysctl_prog.c

2020-11-05T10:43:17+00:00

[ Upstream commit 6e057fc15a2da4ee03eb1fa6889cf687e690106e ]

When tweaking llvm optimizations, I found that selftest build failed
with the following error:
  libbpf: elf: skipping unrecognized data section(6) .rodata.str1.1
  libbpf: prog 'sysctl_tcp_mem': bad map relo against '.L__const.is_tcp_mem.tcp_mem_name'
          in section '.rodata.str1.1'
  Error: failed to open BPF object file: Relocation failed
  make: *** [/work/net-next/tools/testing/selftests/bpf/test_sysctl_prog.skel.h] Error 255
  make: *** Deleting file `/work/net-next/tools/testing/selftests/bpf/test_sysctl_prog.skel.h'

The local string constant "tcp_mem_name" is put into '.rodata.str1.1' section
which libbpf cannot handle. Using untweaked upstream llvm, "tcp_mem_name"
is completely inlined after loop unrolling.

Commit 7fb5eefd7639 ("selftests/bpf: Fix test_sysctl_loop{1, 2}
failure due to clang change") solved a similar problem by defining
the string const as a global. Let us do the same here
for test_sysctl_prog.c so it can weather future potential llvm changes.

Signed-off-by: Yonghong Song 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20200910202718.956042-1-yhs@fb.com
Signed-off-by: Sasha Levin

selftests/bpf: Fix test_sysctl_loop{1, 2} failure due to clang change

2020-10-29T08:58:07+00:00

[ Upstream commit 7fb5eefd76394cfefb380724a87ca40b47d44405 ]

Andrii reported that with latest clang, when building selftests, we have
error likes:
  error: progs/test_sysctl_loop1.c:23:16: in function sysctl_tcp_mem i32 (%struct.bpf_sysctl*):
  Looks like the BPF stack limit of 512 bytes is exceeded.
  Please move large on stack variables into BPF per-cpu array map.

The error is triggered by the following LLVM patch:
  https://reviews.llvm.org/D87134

For example, the following code is from test_sysctl_loop1.c:
  static __always_inline int is_tcp_mem(struct bpf_sysctl *ctx)
  {
    volatile char tcp_mem_name[] = "net/ipv4/tcp_mem/very_very_very_very_long_pointless_string";
    ...
  }
Without the above LLVM patch, the compiler did optimization to load the string
(59 bytes long) with 7 64bit loads, 1 8bit load and 1 16bit load,
occupying 64 byte stack size.

With the above LLVM patch, the compiler only uses 8bit loads, but subregister is 32bit.
So stack requirements become 4 * 59 = 236 bytes. Together with other stuff on
the stack, total stack size exceeds 512 bytes, hence compiler complains and quits.

To fix the issue, removing "volatile" key word or changing "volatile" to
"const"/"static const" does not work, the string is put in .rodata.str1.1 section,
which libbpf did not process it and errors out with
  libbpf: elf: skipping unrecognized data section(6) .rodata.str1.1
  libbpf: prog 'sysctl_tcp_mem': bad map relo against '.L__const.is_tcp_mem.tcp_mem_name'
          in section '.rodata.str1.1'

Defining the string const as global variable can fix the issue as it puts the string constant
in '.rodata' section which is recognized by libbpf. In the future, when libbpf can process
'.rodata.str*.*' properly, the global definition can be changed back to local definition.

Defining tcp_mem_name as a global, however, triggered a verifier failure.
   ./test_progs -n 7/21
  libbpf: load bpf program failed: Permission denied
  libbpf: -- BEGIN DUMP LOG ---
  libbpf:
  invalid stack off=0 size=1
  verification time 6975 usec
  stack depth 160+64
  processed 889 insns (limit 1000000) max_states_per_insn 4 total_states
  14 peak_states 14 mark_read 10

  libbpf: -- END LOG --
  libbpf: failed to load program 'sysctl_tcp_mem'
  libbpf: failed to load object 'test_sysctl_loop2.o'
  test_bpf_verif_scale:FAIL:114
  #7/21 test_sysctl_loop2.o:FAIL
This actually exposed a bpf program bug. In test_sysctl_loop{1,2}, we have code
like
  const char tcp_mem_name[] = "<...long string...>";
  ...
  char name[64];
  ...
  for (i = 0; i < sizeof(tcp_mem_name); ++i)
      if (name[i] != tcp_mem_name[i])
          return 0;
In the above code, if sizeof(tcp_mem_name) > 64, name[i] access may be
out of bound. The sizeof(tcp_mem_name) is 59 for test_sysctl_loop1.c and
79 for test_sysctl_loop2.c.

Without promotion-to-global change, old compiler generates code where
the overflowed stack access is actually filled with valid value, so hiding
the bpf program bug. With promotion-to-global change, the code is different,
more specifically, the previous loading constants to stack is gone, and
"name" occupies stack[-64:0] and overflow access triggers a verifier error.
To fix the issue, adjust "name" buffer size properly.

Reported-by: Andrii Nakryiko 
Signed-off-by: Yonghong Song 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20200909171542.3673449-1-yhs@fb.com
Signed-off-by: Sasha Levin

selftests/bpf: De-flake test_tcpbpf

2020-10-01T11:17:23+00:00

[ Upstream commit ef8c84effce3c7a0b8196fcda8f430c815ab511c ]

It looks like BPF program that handles BPF_SOCK_OPS_STATE_CB state
can race with the bpf_map_lookup_elem("global_map"); I sometimes
see the failures in this test and re-running helps.

Since we know that we expect the callback to be called 3 times (one
time for listener socket, two times for both ends of the connection),
let's export this number and add simple retry logic around that.

Also, let's make EXPECT_EQ() not return on failure, but continue
evaluating all conditions; that should make potential debugging
easier.

With this fix in place I don't observe the flakiness anymore.

Signed-off-by: Stanislav Fomichev 
Signed-off-by: Alexei Starovoitov 
Cc: Lawrence Brakmo 
Link: https://lore.kernel.org/bpf/20191204190955.170934-1-sdf@google.com
Signed-off-by: Sasha Levin

selftests/bpf: Fix massive output from test_maps

2020-09-09T17:12:27+00:00

[ Upstream commit fa4505675e093e895b7ec49a76d44f6b5ad9602e ]

When stdout output from the selftests tool 'test_maps' gets redirected
into e.g file or pipe, then the output lines increase a lot (from 21
to 33949 lines).  This is caused by the printf that happens before the
fork() call, and there are user-space buffered printf data that seems
to be duplicated into the forked process.

To fix this fflush() stdout before the fork loop in __run_parallel().

Fixes: 1a97cf1fe503 ("selftests/bpf: speedup test_maps")
Signed-off-by: Jesper Dangaard Brouer 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/159842985651.1050885.2154399297503372406.stgit@firesoul
Signed-off-by: Sasha Levin

selftests/bpf: test_progs use another shell exit on non-actions

2020-08-21T11:05:31+00:00

[ Upstream commit 3220fb667842a9725cbb71656f406eadb03c094b ]

This is a follow up adjustment to commit 6c92bd5cd465 ("selftests/bpf:
Test_progs indicate to shell on non-actions"), that returns shell exit
indication EXIT_FAILURE (value 1) when user selects a non-existing test.

The problem with using EXIT_FAILURE is that a shell script cannot tell
the difference between a non-existing test and the test failing.

This patch uses value 2 as shell exit indication.
(Aside note unrecognized option parameters use value 64).

Fixes: 6c92bd5cd465 ("selftests/bpf: Test_progs indicate to shell on non-actions")
Signed-off-by: Jesper Dangaard Brouer 
Signed-off-by: Daniel Borkmann 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/159410593992.1093222.90072558386094370.stgit@firesoul
Signed-off-by: Sasha Levin

selftests/bpf: Test_progs indicate to shell on non-actions

2020-08-21T11:05:31+00:00

[ Upstream commit 6c92bd5cd4650c39dd929565ee172984c680fead ]

When a user selects a non-existing test the summary is printed with
indication 0 for all info types, and shell "success" (EXIT_SUCCESS) is
indicated. This can be understood by a human end-user, but for shell
scripting is it useful to indicate a shell failure (EXIT_FAILURE).

Signed-off-by: Jesper Dangaard Brouer 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/159363984736.930467.17956007131403952343.stgit@firesoul
Signed-off-by: Sasha Levin

selftests: bpf: Fix detach from sockmap tests

2020-08-07T07:34:02+00:00

commit f43cb0d672aa8eb09bfdb779de5900c040487d1d upstream.

Fix sockmap tests which rely on old bpf_prog_dispatch behaviour.
In the first case, the tests check that detaching without giving
a program succeeds. Since these are not the desired semantics,
invert the condition. In the second case, the clean up code doesn't
supply the necessary program fds.

Fixes: bb0de3131f4c ("bpf: sockmap: Require attach_bpf_fd when detaching a program")
Reported-by: Martin KaFai Lau 
Signed-off-by: Lorenz Bauer 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Jakub Sitnicki 
Link: https://lore.kernel.org/bpf/20200709115151.75829-1-lmb@cloudflare.com
Signed-off-by: Greg Kroah-Hartman

selftests/bpf, flow_dissector: Close TAP device FD after the test

2020-06-22T07:31:12+00:00

[ Upstream commit b8215dce7dfd817ca38807f55165bf502146cd68 ]

test_flow_dissector leaves a TAP device after it's finished, potentially
interfering with other tests that will run after it. Fix it by closing the
TAP descriptor on cleanup.

Fixes: 0905beec9f52 ("selftests/bpf: run flow dissector tests in skb-less mode")
Signed-off-by: Jakub Sitnicki 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20200531082846.2117903-11-jakub@cloudflare.com
Signed-off-by: Sasha Levin

selftests/bpf: CONFIG_IPV6_SEG6_BPF required for test_seg6_loop.o

2020-06-22T07:31:08+00:00

[ Upstream commit 3c8e8cf4b18b3a7034fab4c4504fc4b54e4b6195 ]

test_seg6_loop.o uses the helper bpf_lwt_seg6_adjust_srh();
it will not be present if CONFIG_IPV6_SEG6_BPF is not specified.

Fixes: b061017f8b4d ("selftests/bpf: add realistic loop tests")
Signed-off-by: Alan Maguire 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/1590147389-26482-2-git-send-email-alan.maguire@oracle.com
Signed-off-by: Sasha Levin