[PATCH] tty: ipwireless: Replace GFP_ATOMIC with GFP_KERNEL in ipwireless_network_create

[PATCH] tty: ipwireless: Replace GFP_ATOMIC with GFP_KERNEL in ipwireless_network_create

[Jia-Ju Bai]

ipwireless_network_create() is never called in atomic context.

The call chain ending up at ipwireless_network_create() is:
[1] ipwireless_network_create() <- config_ipwireless() <- 
	ipwireless_attach()
ipwireless_attach() is only set as ".probe" in struct pcmcia_driver.

Despite never getting called from atomic context,
ipwireless_network_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>
Reviewed-by: David Sterba <dsterba@suse.com>
---
 drivers/tty/ipwireless/network.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/ipwireless/network.c b/drivers/tty/ipwireless/network.c
index c2f9a32..17b04b5 100644
--- a/drivers/tty/ipwireless/network.c
+++ b/drivers/tty/ipwireless/network.c
@@ -415,7 +415,7 @@ void ipwireless_network_packet_received(struct ipw_network *network,
 struct ipw_network *ipwireless_network_create(struct ipw_hardware *hw)
 {
 	struct ipw_network *network =
-		kzalloc(sizeof(struct ipw_network), GFP_ATOMIC);
+		kzalloc(sizeof(struct ipw_network), GFP_KERNEL);
 
 	if (!network)
 		return NULL;
-- 
1.9.1

Re: [PATCH] tty: ipwireless: Replace GFP_ATOMIC with GFP_KERNEL in ipwireless_network_create

[David Sterba]

On Tue, Apr 10, 2018 at 04:31:46PM +0800, Jia-Ju Bai wrote:
> ipwireless_network_create() is never called in atomic context.
> 
> The call chain ending up at ipwireless_network_create() is:
> [1] ipwireless_network_create() <- config_ipwireless() <- 
> 	ipwireless_attach()
> ipwireless_attach() is only set as ".probe" in struct pcmcia_driver.
> 
> Despite never getting called from atomic context,
> ipwireless_network_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>

Reviewed-by: David Sterba <dsterba@suse.com>

We don't have any other patches queued for this driver so it would be
best if this patch goes via net or Greg's tree.

Re: [PATCH] tty: ipwireless: Replace GFP_ATOMIC with GFP_KERNEL in ipwireless_network_create

[Greg KH]

On Wed, Apr 11, 2018 at 01:09:45PM +0200, David Sterba wrote:
> On Tue, Apr 10, 2018 at 04:31:46PM +0800, Jia-Ju Bai wrote:
> > ipwireless_network_create() is never called in atomic context.
> > 
> > The call chain ending up at ipwireless_network_create() is:
> > [1] ipwireless_network_create() <- config_ipwireless() <- 
> > 	ipwireless_attach()
> > ipwireless_attach() is only set as ".probe" in struct pcmcia_driver.
> > 
> > Despite never getting called from atomic context,
> > ipwireless_network_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>
> 
> Reviewed-by: David Sterba <dsterba@suse.com>
> 
> We don't have any other patches queued for this driver so it would be
> best if this patch goes via net or Greg's tree.

I can take it, after 4.17-rc1 is out, thanks!

greg k-h