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From: Dev Jain <dev.jain@arm.com>
To: akpm@linux-foundation.org,
	shuah@kernel.org
Cc: linux-mm@kvack.org,
	linux-kselftest@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Anshuman.Khandual@arm.com,
	sjayaram@akamai.com,
	Dev Jain <dev.jain@arm.com>,
	stable@vger.kernel.org
Subject: [PATCH v2 2/3] selftests/mm: compaction_test: Fix incorrect write of zero to nr_hugepages
Date: Tue, 21 May 2024 13:13:57 +0530
Message-Id: <20240521074358.675031-3-dev.jain@arm.com>
In-Reply-To: <20240521074358.675031-1-dev.jain@arm.com>
References: <20240521074358.675031-1-dev.jain@arm.com>
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Currently, the test tries to set nr_hugepages to zero, but that is not
actually done because the file offset is not reset after read(). Fix that
using lseek().

Fixes: bd67d5c15cc1 ("Test compaction of mlocked memory")
Cc: stable@vger.kernel.org
Signed-off-by: Dev Jain <dev.jain@arm.com>
---
 tools/testing/selftests/mm/compaction_test.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/testing/selftests/mm/compaction_test.c b/tools/testing/selftests/mm/compaction_test.c
index 0b249a06a60b..5e9bd1da9370 100644
--- a/tools/testing/selftests/mm/compaction_test.c
+++ b/tools/testing/selftests/mm/compaction_test.c
@@ -108,6 +108,8 @@ int check_compaction(unsigned long mem_free, unsigned long hugepage_size)
 		goto close_fd;
 	}
 
+	lseek(fd, 0, SEEK_SET);
+
 	/* Start with the initial condition of 0 huge pages*/
 	if (write(fd, "0", sizeof(char)) != sizeof(char)) {
 		ksft_print_msg("Failed to write 0 to /proc/sys/vm/nr_hugepages: %s\n",
-- 
2.34.1