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From: Krzesimir Nowak <>
	Krzesimir Nowak <>,
	Shuah Khan <>,
	Alexei Starovoitov <>,
	Daniel Borkmann <>,
	Martin KaFai Lau <>, Song Liu <>,
	Yonghong Song <>, Andrey Ignatov <>,
	Jiong Wang <>,
	Jakub Kicinski <>,,,
Subject: [PATCH bpf v1 0/3] Test the 32bit narrow reads
Date: Wed, 15 May 2019 15:47:25 +0200	[thread overview]
Message-ID: <> (raw)

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

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(-)


             reply	other threads:[~2019-05-15 13:48 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-15 13:47 Krzesimir Nowak [this message]
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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