linux/net/devlink/devl_internal.h
Jakub Kicinski 93e71edfd9 devlink: keep the instance mutex alive until references are gone
The reference needs to keep the instance memory around, but also
the instance lock must remain valid. Users will take the lock,
check registration status and release the lock. mutex_destroy()
etc. belong in the same place as the freeing of the memory.

Unfortunately lockdep_unregister_key() sleeps so we need
to switch the an rcu_work.

Note that the problem is a bit hard to repro, because
devlink_pernet_pre_exit() iterates over registered instances.
AFAIU the instances must get devlink_free()d concurrently with
the namespace getting deleted for the problem to occur.

Reported-by: syzbot+d94d214ea473e218fc89@syzkaller.appspotmail.com
Reported-by: syzbot+9f0dd863b87113935acf@syzkaller.appspotmail.com
Fixes: 9053637e0d ("devlink: remove the registration guarantee of references")
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20230111042908.988199-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-01-11 20:49:32 -08:00

207 lines
6.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Copyright (c) 2016 Mellanox Technologies. All rights reserved.
* Copyright (c) 2016 Jiri Pirko <jiri@mellanox.com>
*/
#include <linux/mutex.h>
#include <linux/netdevice.h>
#include <linux/notifier.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <linux/xarray.h>
#include <net/devlink.h>
#include <net/net_namespace.h>
#define DEVLINK_REGISTERED XA_MARK_1
#define DEVLINK_RELOAD_STATS_ARRAY_SIZE \
(__DEVLINK_RELOAD_LIMIT_MAX * __DEVLINK_RELOAD_ACTION_MAX)
struct devlink_dev_stats {
u32 reload_stats[DEVLINK_RELOAD_STATS_ARRAY_SIZE];
u32 remote_reload_stats[DEVLINK_RELOAD_STATS_ARRAY_SIZE];
};
struct devlink {
u32 index;
struct xarray ports;
struct list_head rate_list;
struct list_head sb_list;
struct list_head dpipe_table_list;
struct list_head resource_list;
struct list_head param_list;
struct list_head region_list;
struct list_head reporter_list;
struct mutex reporters_lock; /* protects reporter_list */
struct devlink_dpipe_headers *dpipe_headers;
struct list_head trap_list;
struct list_head trap_group_list;
struct list_head trap_policer_list;
struct list_head linecard_list;
struct mutex linecards_lock; /* protects linecard_list */
const struct devlink_ops *ops;
u64 features;
struct xarray snapshot_ids;
struct devlink_dev_stats stats;
struct device *dev;
possible_net_t _net;
/* Serializes access to devlink instance specific objects such as
* port, sb, dpipe, resource, params, region, traps and more.
*/
struct mutex lock;
struct lock_class_key lock_key;
u8 reload_failed:1;
refcount_t refcount;
struct rcu_work rwork;
struct notifier_block netdevice_nb;
char priv[] __aligned(NETDEV_ALIGN);
};
extern struct xarray devlinks;
extern struct genl_family devlink_nl_family;
/* devlink instances are open to the access from the user space after
* devlink_register() call. Such logical barrier allows us to have certain
* expectations related to locking.
*
* Before *_register() - we are in initialization stage and no parallel
* access possible to the devlink instance. All drivers perform that phase
* by implicitly holding device_lock.
*
* After *_register() - users and driver can access devlink instance at
* the same time.
*/
#define ASSERT_DEVLINK_REGISTERED(d) \
WARN_ON_ONCE(!xa_get_mark(&devlinks, (d)->index, DEVLINK_REGISTERED))
#define ASSERT_DEVLINK_NOT_REGISTERED(d) \
WARN_ON_ONCE(xa_get_mark(&devlinks, (d)->index, DEVLINK_REGISTERED))
/* Iterate over devlink pointers which were possible to get reference to.
* devlink_put() needs to be called for each iterated devlink pointer
* in loop body in order to release the reference.
*/
#define devlinks_xa_for_each_registered_get(net, index, devlink) \
for (index = 0; (devlink = devlinks_xa_find_get(net, &index)); index++)
struct devlink *devlinks_xa_find_get(struct net *net, unsigned long *indexp);
static inline bool devl_is_registered(struct devlink *devlink)
{
/* To prevent races the caller must hold the instance lock
* or another lock taken during unregistration.
*/
return xa_get_mark(&devlinks, devlink->index, DEVLINK_REGISTERED);
}
/* Netlink */
#define DEVLINK_NL_FLAG_NEED_PORT BIT(0)
#define DEVLINK_NL_FLAG_NEED_DEVLINK_OR_PORT BIT(1)
#define DEVLINK_NL_FLAG_NEED_RATE BIT(2)
#define DEVLINK_NL_FLAG_NEED_RATE_NODE BIT(3)
#define DEVLINK_NL_FLAG_NEED_LINECARD BIT(4)
enum devlink_multicast_groups {
DEVLINK_MCGRP_CONFIG,
};
/* state held across netlink dumps */
struct devlink_nl_dump_state {
unsigned long instance;
int idx;
union {
/* DEVLINK_CMD_REGION_READ */
struct {
u64 start_offset;
};
/* DEVLINK_CMD_HEALTH_REPORTER_DUMP_GET */
struct {
u64 dump_ts;
};
};
};
struct devlink_gen_cmd {
int (*dump_one)(struct sk_buff *msg, struct devlink *devlink,
struct netlink_callback *cb);
};
/* Iterate over registered devlink instances for devlink dump.
* devlink_put() needs to be called for each iterated devlink pointer
* in loop body in order to release the reference.
* Note: this is NOT a generic iterator, it makes assumptions about the use
* of @state and can only be used once per dumpit implementation.
*/
#define devlink_dump_for_each_instance_get(msg, state, devlink) \
for (; (devlink = devlinks_xa_find_get(sock_net(msg->sk), \
&state->instance)); \
state->instance++, state->idx = 0)
extern const struct genl_small_ops devlink_nl_ops[56];
struct devlink *
devlink_get_from_attrs_lock(struct net *net, struct nlattr **attrs);
void devlink_notify_unregister(struct devlink *devlink);
void devlink_notify_register(struct devlink *devlink);
int devlink_nl_instance_iter_dump(struct sk_buff *msg,
struct netlink_callback *cb);
static inline struct devlink_nl_dump_state *
devlink_dump_state(struct netlink_callback *cb)
{
NL_ASSET_DUMP_CTX_FITS(struct devlink_nl_dump_state);
return (struct devlink_nl_dump_state *)cb->ctx;
}
/* gen cmds */
extern const struct devlink_gen_cmd devl_gen_inst;
extern const struct devlink_gen_cmd devl_gen_port;
extern const struct devlink_gen_cmd devl_gen_sb;
extern const struct devlink_gen_cmd devl_gen_sb_pool;
extern const struct devlink_gen_cmd devl_gen_sb_port_pool;
extern const struct devlink_gen_cmd devl_gen_sb_tc_pool_bind;
extern const struct devlink_gen_cmd devl_gen_selftests;
extern const struct devlink_gen_cmd devl_gen_param;
extern const struct devlink_gen_cmd devl_gen_region;
extern const struct devlink_gen_cmd devl_gen_info;
extern const struct devlink_gen_cmd devl_gen_trap;
extern const struct devlink_gen_cmd devl_gen_trap_group;
extern const struct devlink_gen_cmd devl_gen_trap_policer;
/* Ports */
int devlink_port_netdevice_event(struct notifier_block *nb,
unsigned long event, void *ptr);
struct devlink_port *
devlink_port_get_from_info(struct devlink *devlink, struct genl_info *info);
/* Reload */
bool devlink_reload_actions_valid(const struct devlink_ops *ops);
int devlink_reload(struct devlink *devlink, struct net *dest_net,
enum devlink_reload_action action,
enum devlink_reload_limit limit,
u32 *actions_performed, struct netlink_ext_ack *extack);
static inline bool devlink_reload_supported(const struct devlink_ops *ops)
{
return ops->reload_down && ops->reload_up;
}
/* Line cards */
struct devlink_linecard;
struct devlink_linecard *
devlink_linecard_get_from_info(struct devlink *devlink, struct genl_info *info);
void devlink_linecard_put(struct devlink_linecard *linecard);
/* Rates */
extern const struct devlink_gen_cmd devl_gen_rate_get;
struct devlink_rate *
devlink_rate_get_from_info(struct devlink *devlink, struct genl_info *info);
struct devlink_rate *
devlink_rate_node_get_from_info(struct devlink *devlink,
struct genl_info *info);