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From: Mike Rapoport <rppt@kernel.org>
To: Mahad Ibrahim <mahad.ibrahim.dev@gmail.com>
Cc: Kees Cook <kees@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] lkdtm: use kmalloc() instead of __get_free_page
Date: Sun, 26 Jul 2026 10:03:31 +0300	[thread overview]
Message-ID: <amWxQ0bf4msx9PXT@kernel.org> (raw)
In-Reply-To: <20260722230246.2869-1-mahad.ibrahim.dev@gmail.com>

On Wed, Jul 22, 2026 at 11:02:46PM +0000, Mahad Ibrahim wrote:
> lkdtm_debugfs_entry and direct_entry use __get_free_page to allocate a
> temporary buffer, perform copy_from_user to get the crashtype name,
> strim() to strip whitespace and find_crashtype to find the corresponding
> crashtype that is being requested.
> 
> The lkdtm_debugfs_read uses __get_free_page to allocate a temporary
> buffer to store all the available crashtypes, and then copy it to
> userspace.
> 
> The buffers that are allocated can be allocated with kmalloc as there is
> nothing special that requires a struct page, or the page allocator.
> 
> kmalloc() additionally provides a better API that doesn't require ugly
> casts which obfuscate the code and kfree does not need to know the size
> of the freed object.
> 
> Replace use of __get_free_page() with kmalloc().
> 
> Signed-off-by: Mahad Ibrahim <mahad.ibrahim.dev@gmail.com>

Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

> ---
>  drivers/misc/lkdtm/core.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)

-- 
Sincerely yours,
Mike.


      parent reply	other threads:[~2026-07-26  7:03 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-22 23:02 [PATCH] lkdtm: use kmalloc() instead of __get_free_page Mahad Ibrahim
2026-07-22 23:42 ` Mahad Ibrahim
2026-07-23  3:47   ` Kees Cook
2026-07-24  9:51     ` Mahad Ibrahim
2026-07-26  7:02     ` Mike Rapoport
2026-07-23  8:45 ` David Laight
2026-07-23  9:00   ` Arnd Bergmann
2026-07-24 10:29     ` Mahad Ibrahim
2026-07-26  7:06   ` Mike Rapoport
2026-07-26  7:03 ` Mike Rapoport [this message]

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