On 04/11/2018 06:24 PM, Jia-Ju Bai wrote:
> tipc_mon_create() is never called in atomic context.
>
> The call chain ending up at tipc_mon_create() is:
> [1] tipc_mon_create() <- tipc_enable_bearer() <- tipc_nl_bearer_enable()
> tipc_nl_bearer_enable() calls rtnl_lock(), which indicates this function
> is not called in atomic context.
>
> Despite never getting called from atomic context,
> tipc_mon_create() calls kzalloc() with GFP_ATOMIC,
> which does not sleep for allocation.
> GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
> which can sleep and improve the possibility of successful allocation.
>
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
>
> Signed-off-by: Jia-Ju Bai <baijiaju1...@gmail.com>
Acked-by: Ying Xue <ying....@windriver.com>
> ---
> v2:
> * Modify the description of GFP_ATOMIC in v1.
> Thank Eric for good advice.
> v3:
> * Modify wrong text in description in v2.
> Thank Ying for good advice.
> ---
> net/tipc/monitor.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c
> index 9e109bb..9714d80 100644
> --- a/net/tipc/monitor.c
> +++ b/net/tipc/monitor.c
> @@ -604,9 +604,9 @@ int tipc_mon_create(struct net *net, int bearer_id)
> if (tn->monitors[bearer_id])
> return 0;
>
> - mon = kzalloc(sizeof(*mon), GFP_ATOMIC);
> - self = kzalloc(sizeof(*self), GFP_ATOMIC);
> - dom = kzalloc(sizeof(*dom), GFP_ATOMIC);
> + mon = kzalloc(sizeof(*mon), GFP_KERNEL);
> + self = kzalloc(sizeof(*self), GFP_KERNEL);
> + dom = kzalloc(sizeof(*dom), GFP_KERNEL);
> if (!mon || !self || !dom) {
> kfree(mon);
> kfree(self);
>
