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| author | Jakub Kicinski <kuba@kernel.org> | 2020-08-26 12:40:06 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-09-12 13:40:23 +0200 |
| commit | 9f313bcb3b3d021f9b2f04f6d8464f8e9e309452 (patch) | |
| tree | 76bb5daa6c38cf34d5f626c8e1ef4a034714f3b8 /net/core/dev.c | |
| parent | 553d1bb7f4d1d2b86b7527c10be31b2f5f78bd8c (diff) | |
| download | linux-stable-9f313bcb3b3d021f9b2f04f6d8464f8e9e309452.tar.gz linux-stable-9f313bcb3b3d021f9b2f04f6d8464f8e9e309452.tar.bz2 linux-stable-9f313bcb3b3d021f9b2f04f6d8464f8e9e309452.zip | |
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/dev.c')
| -rw-r--r-- | net/core/dev.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 42ba150fa18d..c77d12a35f92 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6196,12 +6196,13 @@ void netif_napi_add(struct net_device *dev, struct napi_struct *napi, pr_err_once("netif_napi_add() called with weight %d on device %s\n", weight, dev->name); napi->weight = weight; - list_add(&napi->dev_list, &dev->napi_list); napi->dev = dev; #ifdef CONFIG_NETPOLL napi->poll_owner = -1; #endif set_bit(NAPI_STATE_SCHED, &napi->state); + set_bit(NAPI_STATE_NPSVC, &napi->state); + list_add_rcu(&napi->dev_list, &dev->napi_list); napi_hash_add(napi); } EXPORT_SYMBOL(netif_napi_add); |