diff options
| author | John Sperbeck <jsperbeck@google.com> | 2025-01-14 02:13:54 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-01-15 02:45:14 +0100 |
| commit | f0d0277796db613c124206544b6dbe95b520ab6c (patch) | |
| tree | 2d2e842b4b1f3475ce8691cfd62ca17422f3603f | |
| parent | net: xilinx: axienet: Fix IRQ coalescing packet count overflow (diff) | |
| download | linux-f0d0277796db613c124206544b6dbe95b520ab6c.tar.xz linux-f0d0277796db613c124206544b6dbe95b520ab6c.zip | |
net: netpoll: ensure skb_pool list is always initialized
When __netpoll_setup() is called directly, instead of through
netpoll_setup(), the np->skb_pool list head isn't initialized.
If skb_pool_flush() is later called, then we hit a NULL pointer
in skb_queue_purge_reason(). This can be seen with this repro,
when CONFIG_NETCONSOLE is enabled as a module:
ip tuntap add mode tap tap0
ip link add name br0 type bridge
ip link set dev tap0 master br0
modprobe netconsole netconsole=4444@10.0.0.1/br0,9353@10.0.0.2/
rmmod netconsole
The backtrace is:
BUG: kernel NULL pointer dereference, address: 0000000000000008
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
... ... ...
Call Trace:
<TASK>
__netpoll_free+0xa5/0xf0
br_netpoll_cleanup+0x43/0x50 [bridge]
do_netpoll_cleanup+0x43/0xc0
netconsole_netdev_event+0x1e3/0x300 [netconsole]
unregister_netdevice_notifier+0xd9/0x150
cleanup_module+0x45/0x920 [netconsole]
__se_sys_delete_module+0x205/0x290
do_syscall_64+0x70/0x150
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Move the skb_pool list setup and initial skb fill into __netpoll_setup().
Fixes: 221a9c1df790 ("net: netpoll: Individualize the skb pool")
Signed-off-by: John Sperbeck <jsperbeck@google.com>
Reviewed-by: Breno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20250114011354.2096812-1-jsperbeck@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/netpoll.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 2e459b9d88eb..96a6ed37d4cc 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -627,6 +627,8 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) const struct net_device_ops *ops; int err; + skb_queue_head_init(&np->skb_pool); + if (ndev->priv_flags & IFF_DISABLE_NETPOLL) { np_err(np, "%s doesn't support polling, aborting\n", ndev->name); @@ -662,6 +664,9 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) strscpy(np->dev_name, ndev->name, IFNAMSIZ); npinfo->netpoll = np; + /* fill up the skb queue */ + refill_skbs(np); + /* last thing to do is link it to the net device structure */ rcu_assign_pointer(ndev->npinfo, npinfo); @@ -681,8 +686,6 @@ int netpoll_setup(struct netpoll *np) struct in_device *in_dev; int err; - skb_queue_head_init(&np->skb_pool); - rtnl_lock(); if (np->dev_name[0]) { struct net *net = current->nsproxy->net_ns; @@ -782,9 +785,6 @@ put_noaddr: } } - /* fill up the skb queue */ - refill_skbs(np); - err = __netpoll_setup(np, ndev); if (err) goto flush; |