Re: [LTP] [PATCH v4] Migrating the libhugetlbfs/testcases/truncate.c test

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> Test Description: Test is used to verify the correct functionality
> and compatibility of the library with the "truncate" system
> call when operating on files residing in a mounted
> huge page filesystem.
> 
> Signed-off-by: Shirisha G <shirisha@linux.ibm.com>
> ---
> v4:
>  --Addressed the below requested changes
>   1. Added SAFE_FTRUNCATE()
>   2. Fixed run test more times (-iN)
>   3. Fixed warning: unused parameter ‘signum’ [-Wunused-parameter]
>   4. Added blank lines wherever needed which helps the readability
>   5. Ran make check and fixed the issues
> ---
> v3:
>  -Addressed the below requested changes 
>   1. Removed RANDOM_CONSTANT
>   2. Made hpage_size and fd to static
>   3. Used a volatile variable as a flag
>      to pass test in the run_test()
>   4. Removed the failure condition for SAFE_MMAP()
>   5. Have setup the handler in the setup()
>   6. Added SAFE_MUNMAP()
>   7. Ran make check and fixed all issues
> ---
> v2:
>  -Corrected typo
> ---
>  runtest/hugetlb                               |  1 +
>  testcases/kernel/mem/.gitignore               |  1 +
>  .../kernel/mem/hugetlb/hugemmap/hugemmap33.c  | 87 +++++++++++++++++++
>  3 files changed, 89 insertions(+)
>  create mode 100644 testcases/kernel/mem/hugetlb/hugemmap/hugemmap33.c
> 
> diff --git a/runtest/hugetlb b/runtest/hugetlb
> index 299c07ac9..1300e80fb 100644
> --- a/runtest/hugetlb
> +++ b/runtest/hugetlb
> @@ -35,6 +35,7 @@ hugemmap29 hugemmap29
>  hugemmap30 hugemmap30
>  hugemmap31 hugemmap31
>  hugemmap32 hugemmap32
> +hugemmap33 hugemmap33
>  hugemmap05_1 hugemmap05 -m
>  hugemmap05_2 hugemmap05 -s
>  hugemmap05_3 hugemmap05 -s -m
> diff --git a/testcases/kernel/mem/.gitignore b/testcases/kernel/mem/.gitignore
> index c96fe8bfc..444acdf52 100644
> --- a/testcases/kernel/mem/.gitignore
> +++ b/testcases/kernel/mem/.gitignore
> @@ -34,6 +34,7 @@
>  /hugetlb/hugemmap/hugemmap30
>  /hugetlb/hugemmap/hugemmap31
>  /hugetlb/hugemmap/hugemmap32
> +/hugetlb/hugemmap/hugemmap33
>  /hugetlb/hugeshmat/hugeshmat01
>  /hugetlb/hugeshmat/hugeshmat02
>  /hugetlb/hugeshmat/hugeshmat03
> diff --git a/testcases/kernel/mem/hugetlb/hugemmap/hugemmap33.c b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap33.c
> new file mode 100644
> index 000000000..eb21e204c
> --- /dev/null
> +++ b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap33.c
> @@ -0,0 +1,87 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2005-2006 IBM Corporation.
> + * Author: David Gibson & Adam Litke
> + */
> +
> +/*\
> + * [Description]
> + *
> + * Test case is used to verify the correct functionality
> + * and compatibility of the library with the "truncate" system call when
> + * operating on files residing in a mounted huge page filesystem.
> + */
> +
> +#include "hugetlb.h"
> +#include <setjmp.h>
> +#include <signal.h>
> +
> +#define MNTPOINT "hugetlbfs/"
> +
> +static long hpage_size;
> +static int fd;
> +static sigjmp_buf sig_escape;
> +static volatile int test_pass;
> +static int sigbus_count;
> +
> +static void sigbus_handler(int signum LTP_ATTRIBUTE_UNUSED)
> +{
> +	test_pass = 1;
> +	siglongjmp(sig_escape, 17);
> +}
> +
> +static void run_test(void)
> +{
> +	void *p;
> +	volatile unsigned int *q;
> +
> +	sigbus_count = 0;
> +	test_pass = 0;
> +
> +	struct sigaction my_sigaction;
> +
> +	my_sigaction.sa_handler = sigbus_handler;
> +	p = SAFE_MMAP(NULL, hpage_size, PROT_READ|PROT_WRITE, MAP_SHARED,
> +			fd, 0);
> +	q = p;
> +	*q = 0;
> +	SAFE_SIGACTION(SIGBUS, &my_sigaction, NULL);
> +
> +	SAFE_FTRUNCATE(fd, 0);
> +
> +	if (sigsetjmp(sig_escape, 1) == 0)
> +		*q;
> +	else
> +		sigbus_count++;
> +

You should reset the SIGBUS handler to SIGDFL here, otherwise all
subsequent runs run with the handler installed during the whole
run_test() function. I suppose that you purposely install it after you
have faulted a page in the file with *q = 0 to jump to the
sigbus_count++ branch.

> +	if (sigbus_count != 1)
> +		tst_res(TFAIL, "Didn't SIGBUS");
> +
> +	if (test_pass == 1)
> +		tst_res(TPASS, "Expected SIGBUS triggered");

This is really redundant. Since we use siglongjmp() we don't need a
variable set in the signal handler. And we have to report some result
either case, so this should really be:

	if (sigbus_count)
		tst_res(TPASS, "Got SIGBUS");
	else
		tst_res(TFAIL, "Haven't got SIGBUS");

> +	SAFE_MUNMAP(p, hpage_size);
> +}
> +
> +
> +static void setup(void)
> +{
> +	hpage_size = tst_get_hugepage_size();
> +	fd = tst_creat_unlinked(MNTPOINT, 0);
> +}
> +
> +static void cleanup(void)
> +{
> +	if (fd > 0)
> +		SAFE_CLOSE(fd);
> +}
> +
> +static struct tst_test test = {
> +	.needs_root = 1,
> +	.mntpoint = MNTPOINT,
> +	.needs_hugetlbfs = 1,
> +	.needs_tmpdir = 1,
> +	.setup = setup,
> +	.cleanup = cleanup,
> +	.test_all = run_test,
> +	.hugepages = {1, TST_NEEDS},
> +};
> -- 
> 2.39.3
> 

> 
> -- 
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-- 
Cyril Hrubis
chrubis@suse.cz

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp