4.20-stable review patch. If anyone has any objections, please let me know.
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From: Josh Elsasser jelsasser@appneta.com
[ Upstream commit 35edfdc77f683c8fd27d7732af06cf6489af60a5 ]
Assign a default net namespace to netdevs created by init_dummy_netdev(). Fixes a NULL pointer dereference caused by busy-polling a socket bound to an iwlwifi wireless device, which bumps the per-net BUSYPOLLRXPACKETS stat if napi_poll() received packets:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000190 IP: napi_busy_loop+0xd6/0x200 Call Trace: sock_poll+0x5e/0x80 do_sys_poll+0x324/0x5a0 SyS_poll+0x6c/0xf0 do_syscall_64+0x6b/0x1f0 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
Fixes: 7db6b048da3b ("net: Commonize busy polling code to focus on napi_id instead of socket") Signed-off-by: Josh Elsasser jelsasser@appneta.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/dev.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/net/core/dev.c +++ b/net/core/dev.c @@ -8624,6 +8624,9 @@ int init_dummy_netdev(struct net_device set_bit(__LINK_STATE_PRESENT, &dev->state); set_bit(__LINK_STATE_START, &dev->state);
+ /* napi_busy_loop stats accounting wants this */ + dev_net_set(dev, &init_net); + /* Note : We dont allocate pcpu_refcnt for dummy devices, * because users of this 'device' dont need to change * its refcount.