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* [PATCH bpf v1 0/3] Test the 32bit narrow reads
@ 2019-05-15 13:47 Krzesimir Nowak
  2019-05-15 13:47 ` [PATCH bpf v1 1/3] selftests/bpf: Test correctness of narrow 32bit read on 64bit field Krzesimir Nowak
                   ` (2 more replies)
  0 siblings, 3 replies; 12+ messages in thread
From: Krzesimir Nowak @ 2019-05-15 13:47 UTC (permalink / raw)
  To: bpf
  Cc: iago, alban, Krzesimir Nowak, Shuah Khan, Alexei Starovoitov,
	Daniel Borkmann, Martin KaFai Lau, Song Liu, Yonghong Song,
	Andrey Ignatov, Jiong Wang, Jakub Kicinski, linux-kselftest,
	netdev, linux-kernel

These patches try to test the fix made in commit e2f7fc0ac695 ("bpf:
fix undefined behavior in narrow load handling"). The problem existed
in the generated BPF bytecode that was doing a 32bit narrow read of a
64bit field, so to test it the code would need to be executed.
Currently the only such field exists in BPF_PROG_TYPE_PERF_EVENT,
which is not supported by bpf_prog_test_run().

First commit adds the test, but since I can't run it, I'm not sure if
it is even valid (because endianness, for example). Second commit adds
a message to test_verifier when it couldn't run the program because of
lack permissions or program type being not supported. Third commit
fixes a possible problem with errno.

With these patches, I get the following output on my test:

/kernel/tools/testing/selftests/bpf$ sudo ./test_verifier 920 920
#920/p 32bit loads of a 64bit field (both least and most significant words) Did not run the program (not supported) OK
Summary: 1 PASSED, 0 SKIPPED, 0 FAILED

So it looks like I need to pick a different approach.

Krzesimir Nowak (3):
  selftests/bpf: Test correctness of narrow 32bit read on 64bit field
  selftests/bpf: Print a message when tester could not run a program
  selftests/bpf: Avoid a clobbering of errno

 tools/testing/selftests/bpf/test_verifier.c   | 19 +++++++++++++++----
 .../testing/selftests/bpf/verifier/var_off.c  | 15 +++++++++++++++
 2 files changed, 30 insertions(+), 4 deletions(-)

-- 
2.20.1


^ permalink raw reply	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2019-05-23 16:27 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-05-15 13:47 [PATCH bpf v1 0/3] Test the 32bit narrow reads Krzesimir Nowak
2019-05-15 13:47 ` [PATCH bpf v1 1/3] selftests/bpf: Test correctness of narrow 32bit read on 64bit field Krzesimir Nowak
2019-05-23 16:02   ` Daniel Borkmann
2019-05-15 13:47 ` [PATCH bpf v1 2/3] selftests/bpf: Print a message when tester could not run a program Krzesimir Nowak
2019-05-15 21:45   ` Jakub Kicinski
2019-05-16  9:29     ` Krzesimir Nowak
2019-05-16 15:50       ` Jakub Kicinski
2019-05-16 16:21         ` Krzesimir Nowak
2019-05-16 16:54           ` Jakub Kicinski
2019-05-15 13:47 ` [PATCH bpf v1 3/3] selftests/bpf: Avoid a clobbering of errno Krzesimir Nowak
2019-05-15 21:50   ` Jakub Kicinski
2019-05-16  9:31     ` Krzesimir Nowak

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