[PATCH] usnic: avoid overly large buffers on stack

From: Arnd Bergmann <arnd@arndb.de>
To: Christian Benvenuti <benve@cisco.com>,
	Nelson Escobar <neescoba@cisco.com>,
	Parvi Kaustubhi <pkaustub@cisco.com>,
	Doug Ledford <dledford@redhat.com>,
	Jason Gunthorpe <jgg@ziepe.ca>
Cc: Arnd Bergmann <arnd@arndb.de>, Leon Romanovsky <leon@kernel.org>,
	Gal Pressman <galpress@amazon.com>,
	Parav Pandit <parav@mellanox.com>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Kamal Heib <kamalheib1@gmail.com>,
	Florian Westphal <fw@strlen.de>,
	linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] usnic: avoid overly large buffers on stack
Date: Fri,  6 Sep 2019 17:57:17 +0200	[thread overview]
Message-ID: <20190906155730.2750200-1-arnd@arndb.de> (raw)

It's never a good idea to put a 1000-byte buffer on the kernel
stack. The compiler warns about this instance when usnic_ib_log_vf()
gets inlined into usnic_ib_pci_probe():

drivers/infiniband/hw/usnic/usnic_ib_main.c:543:12: error: stack frame size of 1044 bytes in function 'usnic_ib_pci_probe' [-Werror,-Wframe-larger-than=]

As this is only called for debugging purposes in the setup path,
it's trivial to convert to a dynamic allocation.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/infiniband/hw/usnic/usnic_ib_main.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/usnic/usnic_ib_main.c b/drivers/infiniband/hw/usnic/usnic_ib_main.c
index 03f54eb9404b..c9abe1c01e4e 100644
--- a/drivers/infiniband/hw/usnic/usnic_ib_main.c
+++ b/drivers/infiniband/hw/usnic/usnic_ib_main.c
@@ -89,9 +89,15 @@ static void usnic_ib_dump_vf(struct usnic_ib_vf *vf, char *buf, int buf_sz)
 
 void usnic_ib_log_vf(struct usnic_ib_vf *vf)
 {
-	char buf[1000];
-	usnic_ib_dump_vf(vf, buf, sizeof(buf));
+	char *buf = kzalloc(1000, GFP_KERNEL);
+
+	if (!buf)
+		return;
+
+	usnic_ib_dump_vf(vf, buf, 1000);
 	usnic_dbg("%s\n", buf);
+
+	kfree(buf);
 }
 
 /* Start of netdev section */
-- 
2.20.0

