diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2020-08-26 22:40:06 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-09-12 12:47:40 +0300 |
| commit | 6048d57b66d724a3aa0faf52bf3eb2126396450f (patch) | |
| tree | 4aeed4a4693c3b5dd0a0fbd22bc8d162c4e8102a /net/core/netpoll.c | |
| parent | 20e63db77149deb52d76ff9c8e7ddd3349c390ea (diff) | |
| download | linux-6048d57b66d724a3aa0faf52bf3eb2126396450f.tar.xz | |
net: disable netpoll on fresh napis
[ Upstream commit 96e97bc07e90f175a8980a22827faf702ca4cb30 ]
napi_disable() makes sure to set the NAPI_STATE_NPSVC bit to prevent
netpoll from accessing rings before init is complete. However, the
same is not done for fresh napi instances in netif_napi_add(),
even though we expect NAPI instances to be added as disabled.
This causes crashes during driver reconfiguration (enabling XDP,
changing the channel count) - if there is any printk() after
netif_napi_add() but before napi_enable().
To ensure memory ordering is correct we need to use RCU accessors.
Reported-by: Rob Sherwood <rsher@fb.com>
Fixes: 2d8bff12699a ("netpoll: Close race condition between poll_one_napi and napi_disable")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/core/netpoll.c')
| -rw-r--r-- | net/core/netpoll.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 5de180a9b7f5..9c1bad3909bd 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -178,7 +178,7 @@ static void poll_napi(struct net_device *dev) { struct napi_struct *napi; - list_for_each_entry(napi, &dev->napi_list, dev_list) { + list_for_each_entry_rcu(napi, &dev->napi_list, dev_list) { if (napi->poll_owner != smp_processor_id() && spin_trylock(&napi->poll_lock)) { poll_one_napi(napi); |