Hi Rusty,
At Tue, 12 Mar 2013 15:43:33 -0700,
Greg Kroah-Hartman wrote:
>
> 3.4-stable review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> From: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
>
> commit f7f154f1246ccc5a0a7e9ce50932627d60a0c878 upstream.
>
> virtio_rng feeds the randomness buffer handed by the core directly
> into the scatterlist, since commit bb347d98079a547e80bd4722dee1de61e4dca0e8.
>
> However, if CONFIG_HW_RANDOM=m, the static buffer isn't a linear address
> (at least on most archs). We could fix this in virtio_rng, but it's actually
> far easier to just do it in the core as virtio_rng would have to allocate
> a buffer every time (it doesn't know how much the core will want to read).
>
> Reported-by: Aurelien Jarno <aurelien@xxxxxxxxxxx>
> Tested-by: Aurelien Jarno <aurelien@xxxxxxxxxxx>
> Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>
> ---
> drivers/char/hw_random/core.c | 19 ++++++++++++++++---
> 1 file changed, 16 insertions(+), 3 deletions(-)
>
> --- a/drivers/char/hw_random/core.c
> +++ b/drivers/char/hw_random/core.c
> @@ -40,6 +40,7 @@
> #include <linux/init.h>
> #include <linux/miscdevice.h>
> #include <linux/delay.h>
> +#include <linux/slab.h>
> #include <asm/uaccess.h>
>
>
> @@ -52,8 +53,12 @@ static struct hwrng *current_rng;
> static LIST_HEAD(rng_list);
> static DEFINE_MUTEX(rng_mutex);
> static int data_avail;
> -static u8 rng_buffer[SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES]
> - __cacheline_aligned;
> +static u8 *rng_buffer;
> +
> +static size_t rng_buffer_size(void)
> +{
> + return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES;
> +}
>
> static inline int hwrng_init(struct hwrng *rng)
> {
> @@ -116,7 +121,7 @@ static ssize_t rng_dev_read(struct file
>
> if (!data_avail) {
> bytes_read = rng_get_data(current_rng, rng_buffer,
> - sizeof(rng_buffer),
> + rng_buffer_size(),
> !(filp->f_flags & O_NONBLOCK));
> if (bytes_read < 0) {
> err = bytes_read;
> @@ -307,6 +312,14 @@ int hwrng_register(struct hwrng *rng)
>
> mutex_lock(&rng_mutex);
>
> + /* kmalloc makes this safe for virt_to_page() in virtio_rng.c */
> + err = -ENOMEM;
> + if (!rng_buffer) {
> + rng_buffer = kmalloc(rng_buffer_size(), GFP_KERNEL);
rng_buffer is now kmalloc-ed, but not kfree-ed. Shoudn't it be kfree-ed
at hwrng_unregister()? If my suspect is correct, the same problem is
in 3.8.3-rc1 and 3.0.69-rc1. I'm OK to make a patch, but it'll be after
some hours.
Corecct me if I'm wrong.
Thanks,
Satoru
> + if (!rng_buffer)
> + goto out_unlock;
> + }
> +
> /* Must not register two RNGs with the same name. */
> err = -EEXIST;
> list_for_each_entry(tmp, &rng_list, list) {
>
>
> --
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