linux-kernel - Re: [PATCH] ext4: Fix potential null dereference in ext4 test

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Message-ID: <Z8w43zQ2KVUPbxFi@qasdev.system>
Date: Sat, 8 Mar 2025 12:32:42 +0000
From: Qasim Ijaz <qasdev00@...il.com>
To: Charles Han <hanchunchao@...pur.com>
Cc: adilger.kernel@...ger.ca, tytso@....edu, linux-ext4@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ext4: Fix potential null dereference in ext4 test

On Fri, Mar 07, 2025 at 07:54:31PM +0800, Charles Han wrote:
> kunit_kzalloc() may return a NULL pointer, dereferencing it without
> NULL check may lead to NULL dereference.
> Add a NULL check for test_state
> 
> Fixes: b7098e1fa7bc ("ext4: Add unit test for mb_free_blocks")
> Fixes: ac96b56a2fbd ("ext4: Add unit test for mb_mark_used")
> Signed-off-by: Charles Han <hanchunchao@...pur.com>
> ---
>  fs/ext4/mballoc-test.c | 2 ++
>  1 file changed, 2 insertions(+)

Hi Charles,

I already submitted a patch for this on 5th March, link below:

Link: <https://lore.kernel.org/linux-ext4/20250305124012.28500-1-qasdev00@gmail.com/T/#u>

Thanks,
Qasim
> 
> diff --git a/fs/ext4/mballoc-test.c b/fs/ext4/mballoc-test.c
> index bb2a223b207c..d634c12f1984 100644
> --- a/fs/ext4/mballoc-test.c
> +++ b/fs/ext4/mballoc-test.c
> @@ -796,6 +796,7 @@ static void test_mb_mark_used(struct kunit *test)
>  	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buddy);
>  	grp = kunit_kzalloc(test, offsetof(struct ext4_group_info,
>  				bb_counters[MB_NUM_ORDERS(sb)]), GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, grp);
>  
>  	ret = ext4_mb_load_buddy(sb, TEST_GOAL_GROUP, &e4b);
>  	KUNIT_ASSERT_EQ(test, ret, 0);
> @@ -860,6 +861,7 @@ static void test_mb_free_blocks(struct kunit *test)
>  	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buddy);
>  	grp = kunit_kzalloc(test, offsetof(struct ext4_group_info,
>  				bb_counters[MB_NUM_ORDERS(sb)]), GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, grp);
>  
>  	ret = ext4_mb_load_buddy(sb, TEST_GOAL_GROUP, &e4b);
>  	KUNIT_ASSERT_EQ(test, ret, 0);
> -- 
> 2.43.0
>