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From: Theodore Ts'o <tytso@mit.edu>
To: Ruslan Bilovol <ruslan.bilovol@ti.com>
Cc: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] jbd2: check bh->b_data for NULL in jbd2_journal_get_descriptor_buffer before memset()
Date: Mon, 3 Jun 2013 11:33:23 -0400	[thread overview]
Message-ID: <20130603153323.GB20009@thunk.org> (raw)
In-Reply-To: <1370253616-8173-2-git-send-email-ruslan.bilovol@ti.com>

On Mon, Jun 03, 2013 at 01:00:15PM +0300, Ruslan Bilovol wrote:
> The memset() doesn't perform any NULL-pointer checking
> before dereferencing passed pointer so this should be
> checked before calling it.

I can see that __getblk() can return NULL if there is a memory
allocation failure (and is defined to do so), so checking to make sure
bh is not NULL is a good thing to do.

Have you actually seen a case where bh is non-NULL, but bh->b_data is
NULL?  If not, it might be better to do something like this:

>  	bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
	if (!bh)
		return NULL;
	BUG_ON(!bh->b_data);

						- Ted

  reply	other threads:[~2013-06-03 15:33 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-03 10:00 [PATCH 0/2] Misc ext4 fixes Ruslan Bilovol
2013-06-03 10:00 ` [PATCH 1/2] jbd2: check bh->b_data for NULL in jbd2_journal_get_descriptor_buffer before memset() Ruslan Bilovol
2013-06-03 15:33   ` Theodore Ts'o [this message]
2013-06-04 11:15     ` Ruslan Bilovol
2013-06-04 13:37       ` Theodore Ts'o
2013-06-06  8:02         ` Ruslan Bilovol
2013-06-03 10:00 ` [PATCH 2/2] ext4: add sanity checks in __ext4_check_dir_entry Ruslan Bilovol
2013-06-03 15:40   ` Theodore Ts'o
2013-06-04 11:17     ` Ruslan Bilovol

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