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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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c9fbd71f73
This fixes a problem introduced by:
commit 2cde6acd49 ("netpoll: Fix __netpoll_rcu_free so that it can hold the rtnl lock")
When using netconsole on a bond, __netpoll_cleanup can asynchronously
recurse multiple times, each __netpoll_free_async call can result in
more __netpoll_free_async's. This means there is now a race between
cleanup_work queues on multiple netpoll_info's on multiple devices and
the configuration of a new netpoll. For example if a netconsole is set
to enable 0, reconfigured, and enable 1 immediately, this netconsole
will likely not work.
Given the reason for __netpoll_free_async is it can be called when rtnl
is not locked, if it is locked, we should be able to execute
synchronously. It appears to be locked everywhere it's called from.
Generalize the design pattern from the teaming driver for current
callers of __netpoll_free_async.
CC: Neil Horman <nhorman@tuxdriver.com>
CC: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Debabrata Banerjee <dbanerje@akamai.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
122 lines
2.7 KiB
C
122 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Common code for low-level network console, dump, and debugger code
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*
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* Derived from netconsole, kgdb-over-ethernet, and netdump patches
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*/
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#ifndef _LINUX_NETPOLL_H
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#define _LINUX_NETPOLL_H
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#include <linux/netdevice.h>
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#include <linux/interrupt.h>
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#include <linux/rcupdate.h>
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#include <linux/list.h>
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#include <linux/refcount.h>
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union inet_addr {
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__u32 all[4];
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__be32 ip;
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__be32 ip6[4];
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struct in_addr in;
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struct in6_addr in6;
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};
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struct netpoll {
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struct net_device *dev;
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char dev_name[IFNAMSIZ];
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const char *name;
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union inet_addr local_ip, remote_ip;
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bool ipv6;
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u16 local_port, remote_port;
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u8 remote_mac[ETH_ALEN];
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};
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struct netpoll_info {
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refcount_t refcnt;
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struct semaphore dev_lock;
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struct sk_buff_head txq;
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struct delayed_work tx_work;
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struct netpoll *netpoll;
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struct rcu_head rcu;
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};
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#ifdef CONFIG_NETPOLL
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void netpoll_poll_dev(struct net_device *dev);
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void netpoll_poll_disable(struct net_device *dev);
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void netpoll_poll_enable(struct net_device *dev);
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#else
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static inline void netpoll_poll_disable(struct net_device *dev) { return; }
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static inline void netpoll_poll_enable(struct net_device *dev) { return; }
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#endif
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void netpoll_send_udp(struct netpoll *np, const char *msg, int len);
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void netpoll_print_options(struct netpoll *np);
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int netpoll_parse_options(struct netpoll *np, char *opt);
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int __netpoll_setup(struct netpoll *np, struct net_device *ndev);
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int netpoll_setup(struct netpoll *np);
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void __netpoll_cleanup(struct netpoll *np);
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void __netpoll_free(struct netpoll *np);
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void netpoll_cleanup(struct netpoll *np);
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void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
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struct net_device *dev);
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static inline void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
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{
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unsigned long flags;
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local_irq_save(flags);
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netpoll_send_skb_on_dev(np, skb, np->dev);
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local_irq_restore(flags);
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}
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#ifdef CONFIG_NETPOLL
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static inline void *netpoll_poll_lock(struct napi_struct *napi)
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{
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struct net_device *dev = napi->dev;
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if (dev && dev->npinfo) {
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int owner = smp_processor_id();
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while (cmpxchg(&napi->poll_owner, -1, owner) != -1)
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cpu_relax();
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return napi;
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}
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return NULL;
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}
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static inline void netpoll_poll_unlock(void *have)
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{
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struct napi_struct *napi = have;
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if (napi)
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smp_store_release(&napi->poll_owner, -1);
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}
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static inline bool netpoll_tx_running(struct net_device *dev)
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{
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return irqs_disabled();
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}
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#else
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static inline void *netpoll_poll_lock(struct napi_struct *napi)
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{
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return NULL;
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}
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static inline void netpoll_poll_unlock(void *have)
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{
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}
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static inline void netpoll_netdev_init(struct net_device *dev)
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{
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}
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static inline bool netpoll_tx_running(struct net_device *dev)
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{
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return false;
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}
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#endif
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#endif
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