[Devel] [PATCH RHEL7 COMMIT] ploop: fix typo in ploop_pb_get_first_req_from_tree

[Konstantin Khorenko]

Please consider to create a ReadyKernel patch for this.

https://readykernel.com/

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

On 07/13/2017 01:49 PM, Konstantin Khorenko wrote:
> The commit is pushed to "branch-rh7-3.10.0-514.26.1.vz7.33.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
> after rh7-3.10.0-514.26.1.vz7.33.5
> ------>
> commit b6bd12ecf7c66c26883843d9dc58c0964dc1c0a8
> Author: Maxim Patlasov <mpatlasov at virtuozzo.com>
> Date:   Thu Jul 13 14:49:09 2017 +0400
>
>     ploop: fix typo in ploop_pb_get_first_req_from_tree
>
>     Due to a typo, local pointer was defined as static leading to a nasty race:
>
>     1. Thread A (handling ploopN) initializes that pointer
>     2. Thread B (handling ploopM) re-initialize the same pointer
>     3. Thread A proceeds with using the pointer that currently points to
>     some request belonging to ploopM.
>
>     Hence data (ploop requests) leaked from one ploop device to another
>     leading to list corruption.
>
>     https://jira.sw.ru/browse/PSBM-67513
>
>     Signed-off-by: Maxim Patlasov <mpatlasov at virtuozzo.com>
> ---
>  drivers/block/ploop/push_backup.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/block/ploop/push_backup.c b/drivers/block/ploop/push_backup.c
> index ade5fa5..032706e 100644
> --- a/drivers/block/ploop/push_backup.c
> +++ b/drivers/block/ploop/push_backup.c
> @@ -598,7 +598,7 @@ ploop_pb_get_first_req_from_tree(struct pb_set *pbs,
>  				 unsigned old_owner)
>  {
>  	struct rb_root *tree = &pbs->tree;
> -	static struct ploop_request *p;
> +	struct ploop_request *p;
>  	struct rb_node *n = rb_first(tree);
>
>  	if (!n)
> .
>