RE: [PATCH] proc: report open files as size in stat() for /proc/pid/fd

[David Laight]

From: Ivan Babrou
> Sent: 20 September 2022 20:06
...
> 
> +static int proc_readfd_count(struct inode *inode)
> +{
> +	struct task_struct *p = get_proc_task(inode);
> +	struct fdtable *fdt;
> +	unsigned int i, size, open_fds = 0;
> +
> +	if (!p)
> +		return -ENOENT;
> +
> +	if (p->files) {
> +		fdt = files_fdtable(p->files);
> +		size = fdt->max_fds;
> +
> +		for (i = size / BITS_PER_LONG; i > 0;)
> +			open_fds += hweight64(fdt->open_fds[--i]);
> +	}
> +
> +	return open_fds;
> +}
> +

Doesn't that need (at least) rcu protection?
There might also be issues reading p->files twice.

	David

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