diff options
| author | Eric Dumazet <edumazet@google.com> | 2026-06-03 18:08:31 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-06-04 18:16:14 -0700 |
| commit | f3c496105472f353ff7428569ea4b6a6a61caf8e (patch) | |
| tree | 47606edc07f229040eaf42deb8440e7c99009cfd | |
| parent | c1424df7ff82598a6deba11a63c433b645ab19bb (diff) | |
| download | linux-f3c496105472f353ff7428569ea4b6a6a61caf8e.tar.gz linux-f3c496105472f353ff7428569ea4b6a6a61caf8e.zip | |
rtnetlink: use dev_isalive() in rtnl_getlink()
rtnl_getlink() uses an RCU lookup to get the netdevice pointer.
When/If rtnl_lock() is used, we should check if the netdevice is not
being dismantled before potentially perform illegal actions.
Move dev_isalive() out of net/core/net-sysfs.c and make it available
in net/core/dev.h.
Return -ENODEV if rtnl_getlink() finds a device which is currently
being dismantled and RTNL is requested.
Fixes: e896e5c0734b ("rtnetlink: do not acquire RTNL in rtnl_getlink() with RTEXT_FILTER_NAME_ONLY")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Link: https://patch.msgid.link/20260603180831.1024716-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/dev.h | 6 | ||||
| -rw-r--r-- | net/core/net-sysfs.c | 6 | ||||
| -rw-r--r-- | net/core/rtnetlink.c | 6 |
3 files changed, 12 insertions, 6 deletions
diff --git a/net/core/dev.h b/net/core/dev.h index 0cf24b8f5008..9e9431440869 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -396,4 +396,10 @@ int dev_get_hwtstamp_phylib(struct net_device *dev, struct kernel_hwtstamp_config *cfg); int net_hwtstamp_validate(const struct kernel_hwtstamp_config *cfg); +/* Caller holds RTNL, netdev->lock or RCU */ +static inline bool dev_isalive(const struct net_device *dev) +{ + return READ_ONCE(dev->reg_state) <= NETREG_REGISTERED; +} + #endif diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 3318b5666e43..0e71c9ed41e8 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -37,12 +37,6 @@ static const char fmt_uint[] = "%u\n"; static const char fmt_ulong[] = "%lu\n"; static const char fmt_u64[] = "%llu\n"; -/* Caller holds RTNL, netdev->lock or RCU */ -static inline int dev_isalive(const struct net_device *dev) -{ - return READ_ONCE(dev->reg_state) <= NETREG_REGISTERED; -} - /* There is a possible ABBA deadlock between rtnl_lock and kernfs_node->active, * when unregistering a net device and accessing associated sysfs files. The * potential deadlock is as follow: diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 652dd008955a..61d095ce1b3b 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -4265,6 +4265,11 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr *nlh, retry: if (need_rtnl) { rtnl_lock(); + if (!dev_isalive(dev)) { + err = -ENODEV; + nskb = NULL; + goto unlock; + } /* Synchronize the carrier state so we don't report a state * that we're not actually going to honour immediately; if * the driver just did a carrier off->on transition, we can @@ -4282,6 +4287,7 @@ retry: nlh->nlmsg_seq, 0, 0, ext_filter_mask, 0, NULL, 0, netnsid, GFP_KERNEL); +unlock: if (need_rtnl) rtnl_unlock(); |