Re: [PATCH] seq_file: replace kzalloc() with kvzalloc()

From: Barry Song
Date: Fri Sep 06 2024 - 05:26:40 EST


On Fri, Sep 6, 2024 at 8:06 PM Hailong Liu <hailong.liu@xxxxxxxx> wrote:
>
> __seq_open_private() uses kzalloc() to allocate a private buffer. However,
> the size of the buffer might be greater than order-3, which may cause
> allocation failure. To address this issue, use kvzalloc instead.

In general, this patch seems sensible, but do we have a specific example
of a driver that uses such a large amount of private data?
Providing a real-world example of a driver with substantial private data could
make this patch more convincing:-)

>
> Signed-off-by: Hailong Liu <hailong.liu@xxxxxxxx>
> ---
> fs/seq_file.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/fs/seq_file.c b/fs/seq_file.c
> index e676c8b0cf5d..cf23143bbb65 100644
> --- a/fs/seq_file.c
> +++ b/fs/seq_file.c
> @@ -621,7 +621,7 @@ int seq_release_private(struct inode *inode, struct file *file)
> {
> struct seq_file *seq = file->private_data;
>
> - kfree(seq->private);
> + kvfree(seq->private);
> seq->private = NULL;
> return seq_release(inode, file);
> }
> @@ -634,7 +634,7 @@ void *__seq_open_private(struct file *f, const struct seq_operations *ops,
> void *private;
> struct seq_file *seq;
>
> - private = kzalloc(psize, GFP_KERNEL_ACCOUNT);
> + private = kvzalloc(psize, GFP_KERNEL_ACCOUNT);
> if (private == NULL)
> goto out;
>
> @@ -647,7 +647,7 @@ void *__seq_open_private(struct file *f, const struct seq_operations *ops,
> return private;
>
> out_free:
> - kfree(private);
> + kvfree(private);
> out:
> return NULL;
> }
> --
> 2.30.0
>
>