lkml.org 
[lkml]   [2018]   [Oct]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [RFC 5/6] pstore: donot treat empty buffers as valid
On Fri, Oct 26, 2018 at 7:00 PM, Joel Fernandes (Google)
<joel@joelfernandes.org> wrote:
> pstore currently calls persistent_ram_save_old even if a buffer is
> empty. While this appears to work, it is simply not the right thing to
> do and could lead to bugs so lets avoid that. It also prevent misleading
> prints in the logs which claim the buffer is valid.

I need to be better convinced that a present zero length record is the
same as a non-present record. This seems true, but there is
potentially still metadata available from a backend. What were the
misleading prints in logs?

-Kees

>
> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> ---
> fs/pstore/ram_core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
> index 0792595ebcfb..1299aa3ea734 100644
> --- a/fs/pstore/ram_core.c
> +++ b/fs/pstore/ram_core.c
> @@ -495,7 +495,7 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
>
> sig ^= PERSISTENT_RAM_SIG;
>
> - if (prz->buffer->sig == sig) {
> + if (prz->buffer->sig == sig && buffer_size(prz)) {
> if (buffer_size(prz) > prz->buffer_size ||
> buffer_start(prz) > buffer_size(prz))
> pr_info("found existing invalid buffer, size %zu, start %zu\n",
> --
> 2.19.1.568.g152ad8e336-goog
>



--
Kees Cook

\
 
 \ /
  Last update: 2018-10-26 21:40    [W:0.111 / U:0.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site