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authorJohannes Berg <johannes.berg@intel.com>2021-03-10 21:58:40 +0100
committerJohannes Berg <johannes.berg@intel.com>2021-03-16 21:20:47 +0100
commit77cbf790e5b482256662e14c8b6ef4fecb07d06d (patch)
treec99bf77a8a0633a62945edf50067dd724e94a0d1 /net/wireless
parent58d25626f6f0ea5bcec3c13387b9f835d188723d (diff)
nl80211: fix locking for wireless device netns change
We have all the network interfaces marked as netns-local since the only reasonable thing to do right now is to set a whole device, including all netdevs, into a different network namespace. For this reason, we also have our own way of changing the network namespace. Unfortunately, the RTNL locking changes broke this, and it now results in many RTNL assertions. The trivial fix for those (just hold RTNL for the changes) however leads to deadlocks in the cfg80211 netdev notifier. Since we only need the wiphy, and that's still protected by the RTNL, add a new NL80211_FLAG_NO_WIPHY_MTX flag to the nl80211 ops and use it to _not_ take the wiphy mutex but only the RTNL. This way, the notifier does all the work necessary during unregistration/registration of the netdevs from the old and in the new namespace. Reported-by: Sid Hayn <sidhayn@gmail.com> Fixes: a05829a7222e ("cfg80211: avoid holding the RTNL when calling the driver") Signed-off-by: Johannes Berg <johannes.berg@intel.com> Link: https://lore.kernel.org/r/20210310215839.eadf7c43781b.I5fc6cf6676f800ab8008e03bbea9c3349b02d804@changeid Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/wireless')
-rw-r--r--net/wireless/nl80211.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 521d36bb0803..ae6097fff133 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -14789,6 +14789,7 @@ bad_tid_conf:
#define NL80211_FLAG_NEED_WDEV_UP (NL80211_FLAG_NEED_WDEV |\
NL80211_FLAG_CHECK_NETDEV_UP)
#define NL80211_FLAG_CLEAR_SKB 0x20
+#define NL80211_FLAG_NO_WIPHY_MTX 0x40
static int nl80211_pre_doit(const struct genl_ops *ops, struct sk_buff *skb,
struct genl_info *info)
@@ -14840,7 +14841,7 @@ static int nl80211_pre_doit(const struct genl_ops *ops, struct sk_buff *skb,
info->user_ptr[0] = rdev;
}
- if (rdev) {
+ if (rdev && !(ops->internal_flags & NL80211_FLAG_NO_WIPHY_MTX)) {
wiphy_lock(&rdev->wiphy);
/* we keep the mutex locked until post_doit */
__release(&rdev->wiphy.mtx);
@@ -14865,7 +14866,8 @@ static void nl80211_post_doit(const struct genl_ops *ops, struct sk_buff *skb,
}
}
- if (info->user_ptr[0]) {
+ if (info->user_ptr[0] &&
+ !(ops->internal_flags & NL80211_FLAG_NO_WIPHY_MTX)) {
struct cfg80211_registered_device *rdev = info->user_ptr[0];
/* we kept the mutex locked since pre_doit */
@@ -15329,7 +15331,9 @@ static const struct genl_small_ops nl80211_small_ops[] = {
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.doit = nl80211_wiphy_netns,
.flags = GENL_UNS_ADMIN_PERM,
- .internal_flags = NL80211_FLAG_NEED_WIPHY,
+ .internal_flags = NL80211_FLAG_NEED_WIPHY |
+ NL80211_FLAG_NEED_RTNL |
+ NL80211_FLAG_NO_WIPHY_MTX,
},
{
.cmd = NL80211_CMD_GET_SURVEY,