* [PATCH v2] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create
@ 2018-04-10 1:17 Jia-Ju Bai
2018-04-11 10:11 ` Ying Xue
0 siblings, 1 reply; 4+ messages in thread
From: Jia-Ju Bai @ 2018-04-10 1:17 UTC (permalink / raw)
To: jon.maloy, ying.xue, davem
Cc: netdev, tipc-discussion, linux-kernel, Jia-Ju Bai
tipc_mon_create() is never called in atomic context.
The call chain ending up at dn_route_init() 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 sucessful 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 <baijiaju1990@gmail.com>
---
v2:
* Modify the description of GFP_ATOMIC in v1.
Thank Eric 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);
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create
2018-04-10 1:17 [PATCH v2] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create Jia-Ju Bai
@ 2018-04-11 10:11 ` Ying Xue
2018-04-11 10:18 ` Jia-Ju Bai
0 siblings, 1 reply; 4+ messages in thread
From: Ying Xue @ 2018-04-11 10:11 UTC (permalink / raw)
To: Jia-Ju Bai, jon.maloy, davem; +Cc: netdev, tipc-discussion, linux-kernel
On 04/10/2018 09:17 AM, Jia-Ju Bai wrote:
> tipc_mon_create() is never called in atomic context.
>
> The call chain ending up at dn_route_init() is:
Sorry, I don't think there is any relationship between the following
call chain with dn_route_init().
> [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 sucessful allocation.
s/sucessful/successful
>
> 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 <baijiaju1990@gmail.com>> ---
> v2:
> * Modify the description of GFP_ATOMIC in v1.
> Thank Eric 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);
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v2] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create
2018-04-11 10:11 ` Ying Xue
@ 2018-04-11 10:18 ` Jia-Ju Bai
0 siblings, 0 replies; 4+ messages in thread
From: Jia-Ju Bai @ 2018-04-11 10:18 UTC (permalink / raw)
To: Ying Xue, jon.maloy, davem; +Cc: netdev, tipc-discussion, linux-kernel
On 2018/4/11 18:11, Ying Xue wrote:
> On 04/10/2018 09:17 AM, Jia-Ju Bai wrote:
>> tipc_mon_create() is never called in atomic context.
>>
>> The call chain ending up at dn_route_init() is:
> Sorry, I don't think there is any relationship between the following
> call chain with dn_route_init().
>
>> [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 sucessful allocation.
> s/sucessful/successful
Thanks for your reply.
I am sorry for my mistakes.
I will revised the text and send a V3.
Jia-Ju Bai
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v2] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create
@ 2018-04-10 1:16 Jia-Ju Bai
0 siblings, 0 replies; 4+ messages in thread
From: Jia-Ju Bai @ 2018-04-10 1:16 UTC (permalink / raw)
To: gerrit, davem; +Cc: dccp, netdev, linux-kernel, Jia-Ju Bai
tipc_mon_create() is never called in atomic context.
The call chain ending up at dn_route_init() 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 sucessful 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 <baijiaju1990@gmail.com>
---
v2:
* Modify the description of GFP_ATOMIC in v1.
Thank Eric 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);
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
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2018-04-10 1:17 [PATCH v2] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create Jia-Ju Bai
2018-04-11 10:11 ` Ying Xue
2018-04-11 10:18 ` Jia-Ju Bai
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2018-04-10 1:16 Jia-Ju Bai
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