From: Eduard Zingerman <eddyz87@gmail.com>
To: bpf@vger.kernel.org, ast@kernel.org
Cc: andrii@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev,
kernel-team@fb.com, yhs@fb.com,
Eduard Zingerman <eddyz87@gmail.com>,
Florian Westphal <fw@strlen.de>
Subject: [PATCH bpf-next 2/4] selftests/bpf: fix __retval() being always ignored
Date: Fri, 21 Apr 2023 02:23:15 +0300 [thread overview]
Message-ID: <20230420232317.2181776-3-eddyz87@gmail.com> (raw)
In-Reply-To: <20230420232317.2181776-1-eddyz87@gmail.com>
Florian Westphal found a bug in and suggested a fix for test_loader.c
processing of __retval tag. Because of this bug the function
test_loader.c:do_prog_test_run() never executed and all __retval test
tags were ignored.
If this bug is fixed a number of test cases from
progs/verifier_array_access.c fail with retval not matching the
expected value. This test was recently converted to use test_loader.c
and inline assembly in [1]. When doing the conversion I missed the
important detail of test_verifier.c operation: when it creates
fixup_map_array_ro, fixup_map_array_wo and fixup_map_array_small it
populates these maps with a dummy record.
Disabling the __retval checks for the affected verifier_array_access
in this commit to avoid false-postivies in any potential bisects.
The issue is addressed in the next patch.
I verified that the __retval tags are now respected by changing
expected return values for all tests annotated with __retval, and
checking that these tests started to fail.
[1] https://lore.kernel.org/bpf/20230325025524.144043-1-eddyz87@gmail.com/
Fixes: 19a8e06f5f91 ("selftests/bpf: Tests execution support for test_loader.c")
Reported-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/bpf/f4c4aee644425842ee6aa8edf1da68f0a8260e7c.camel@gmail.com/T/
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
tools/testing/selftests/bpf/progs/verifier_array_access.c | 4 ++--
tools/testing/selftests/bpf/test_loader.c | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/verifier_array_access.c b/tools/testing/selftests/bpf/progs/verifier_array_access.c
index 95d7ecc12963..fceeeef78721 100644
--- a/tools/testing/selftests/bpf/progs/verifier_array_access.c
+++ b/tools/testing/selftests/bpf/progs/verifier_array_access.c
@@ -330,7 +330,7 @@ l0_%=: exit; \
SEC("socket")
__description("valid read map access into a read-only array 1")
-__success __success_unpriv __retval(28)
+__success __success_unpriv /* __retval(28) temporarily disable */
__naked void a_read_only_array_1_1(void)
{
asm volatile (" \
@@ -351,7 +351,7 @@ l0_%=: exit; \
SEC("tc")
__description("valid read map access into a read-only array 2")
-__success __retval(65507)
+__success /* __retval(65507) temporarily disable */
__naked void a_read_only_array_2_1(void)
{
asm volatile (" \
diff --git a/tools/testing/selftests/bpf/test_loader.c b/tools/testing/selftests/bpf/test_loader.c
index 47e9e076bc8f..e2a1bdc5a570 100644
--- a/tools/testing/selftests/bpf/test_loader.c
+++ b/tools/testing/selftests/bpf/test_loader.c
@@ -587,7 +587,7 @@ void run_subtest(struct test_loader *tester,
/* For some reason test_verifier executes programs
* with all capabilities restored. Do the same here.
*/
- if (!restore_capabilities(&caps))
+ if (restore_capabilities(&caps))
goto tobj_cleanup;
do_prog_test_run(bpf_program__fd(tprog), &retval);
--
2.40.0
next prev parent reply other threads:[~2023-04-20 23:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-20 23:23 [PATCH bpf-next 0/4] fix __retval() being always ignored Eduard Zingerman
2023-04-20 23:23 ` [PATCH bpf-next 1/4] selftests/bpf: disable program test run for progs/refcounted_kptr.c Eduard Zingerman
2023-04-20 23:23 ` Eduard Zingerman [this message]
2023-04-20 23:23 ` [PATCH bpf-next 3/4] selftests/bpf: add pre bpf_prog_test_run_opts() callback for test_loader Eduard Zingerman
2023-04-20 23:23 ` [PATCH bpf-next 4/4] selftests/bpf: populate map_array_ro map for verifier_array_access test Eduard Zingerman
2023-04-21 2:00 ` [PATCH bpf-next 0/4] fix __retval() being always ignored patchwork-bot+netdevbpf
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