Re: [PATCH v2] selftests/harness: Prevent infinite loop due to Assert in FIXTURE_TEARDOWN

From: Shuah Khan
Date: Thu Apr 04 2024 - 12:48:08 EST


On 3/26/24 15:13, Shengyu Li wrote:
This patch addresses an issue in the selftests/harness where an
assertion within FIXTURE_TEARDOWN could trigger an infinite loop.
The problem arises because the teardown procedure is meant to
execute once, but the presence of failing assertions (ASSERT_EQ(0, 1))
leads to repeated attempts to execute teardown due to
the long jump mechanism used by the harness for handling assertions.

To resolve this, the patch ensures that the teardown process
runs only once, regardless of assertion outcomes, preventing
the infinite loop and allowing tests to fail.

A simple test demo(test.c):
#include "kselftest_harness.h"

FIXTURE(f)
{
int fd;
};

FIXTURE_SETUP(f)
{
self->fd = 0;
}

FIXTURE_TEARDOWN(f)
{
TH_LOG("TEARDOWN");
ASSERT_EQ(0, 1);
self->fd = -1;
}

TEST_F(f, open_close)
{
ASSERT_NE(self->fd, 1);
}

TEST_HARNESS_MAIN

will always output the following output due to a dead loop until timeout:
# test.c:15:open_close:TEARDOWN
# test.c:16:open_close:Expected 0 (0) == 1 (1)
# test.c:15:open_close:TEARDOWN
# test.c:16:open_close:Expected 0 (0) == 1 (1)
...

But here's what we should and expect to get:
TAP version 13
1..1
# Starting 1 tests from 2 test cases.
# RUN f.open_close ...
# test.c:15:open_close:TEARDOWN
# test.c:16:open_close:Expected 0 (0) == 1 (1)
# open_close: Test terminated by assertion
# FAIL f.open_close
not ok 1 f.open_close
# FAILED: 0 / 1 tests passed.
# Totals: pass:0 fail:1 xfail:0 xpass:0 skip:0 error:0

also this is related to the issue mentioned in this patch
https://patchwork.kernel.org/project/linux-kselftest/patch/e2ba3f8c-80e6-477d-9cea-1c9af820e0ed@xxxxxxxxxxxx/


Adding people who participated in the above thread discussion.
Please try this patch out to see if this fixes the problem
with iommu test.



Signed-off-by: Shengyu Li <shengyu.li.evgeny@xxxxxxxxx>

Than you for finding and fixing this. Applied now to linux-kselftes fixes
branch for the next rc.

thanks,
-- Shuah