On Fri, 2012-08-03 at 11:17 +0200, Eric Dumazet wrote:

On Fri, 2012-07-27 at 23:37 +0800, Cong Wang wrote:

quoted

slave_enable_netpoll() and __netpoll_setup() may be called
with read_lock() held, so should use GFP_ATOMIC to allocate
memory.

Cc: "David S. Miller" <davem@davemloft.net>
Reported-by: Dan Carpenter <redacted>
Signed-off-by: Cong Wang <redacted>
---
 drivers/net/bonding/bond_main.c |    2 +-
 net/core/netpoll.c              |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 6fae5f3..ab773d4 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c

@@ -1235,7 +1235,7 @@ static inline int slave_enable_netpoll(struct slave *slave)
 	struct netpoll *np;
 	int err = 0;
 
-	np = kzalloc(sizeof(*np), GFP_KERNEL);
+	np = kzalloc(sizeof(*np), GFP_ATOMIC);
 	err = -ENOMEM;
 	if (!np)
 		goto out;

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index b4c90e4..c78a966 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c

@@ -734,7 +734,7 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
 	}
 
 	if (!ndev->npinfo) {
-		npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
+		npinfo = kmalloc(sizeof(*npinfo), GFP_ATOMIC);
 		if (!npinfo) {
 			err = -ENOMEM;
 			goto out;

Yes this works, but maybe you instead could pass/add a gfp_t flags
argument to __netpoll_setup() ?

Management tasks should allow GFP_KERNEL allocations to have less
failure risks.

Its sad bonding uses the rwlock here instead of a mutex

Yup, that is a good idea. I will update this patch.

Thanks!