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[76.102.12.149]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-12a736b952asm749391c88.12.2026.03.19.18.25.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Mar 2026 18:25:05 -0700 (PDT) From: Stanislav Fomichev To: netdev@vger.kernel.org Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, corbet@lwn.net, skhan@linuxfoundation.org, andrew+netdev@lunn.ch, michael.chan@broadcom.com, pavan.chebbi@broadcom.com, anthony.l.nguyen@intel.com, przemyslaw.kitszel@intel.com, saeedm@nvidia.com, tariqt@nvidia.com, mbloch@nvidia.com, alexanderduyck@fb.com, kernel-team@meta.com, johannes@sipsolutions.net, sd@queasysnail.net, jianbol@nvidia.com, dtatulea@nvidia.com, sdf@fomichev.me, mohsin.bashr@gmail.com, jacob.e.keller@intel.com, willemb@google.com, skhawaja@google.com, bestswngs@gmail.com, aleksandr.loktionov@intel.com, kees@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-rdma@vger.kernel.org, linux-wireless@vger.kernel.org, linux-kselftest@vger.kernel.org, leon@kernel.org Subject: [PATCH net-next v3 02/13] wifi: cfg80211: use __rtnl_unlock in nl80211_pre_doit Date: Thu, 19 Mar 2026 18:24:50 -0700 Message-ID: <20260320012501.2033548-3-sdf@fomichev.me> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260320012501.2033548-1-sdf@fomichev.me> References: <20260320012501.2033548-1-sdf@fomichev.me> Precedence: bulk X-Mailing-List: linux-wireless@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit nl80211_pre_doit acquires rtnl_lock and then wiphy_lock, releasing rtnl while keeping wiphy_lock held until post_doit. With the introduction of rx_mode_wq and its flush in netdev_run_todo, calling rtnl_unlock here creates a circular lock dependency: Chain exists of: (wq_completion)rx_mode_wq --> rtnl_mutex --> &rdev->wiphy.mtx Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&rdev->wiphy.mtx); lock(rtnl_mutex); lock(&rdev->wiphy.mtx); lock((wq_completion)rx_mode_wq); Switch to __rtnl_unlock to skip netdev_run_todo in nl80211_pre_doit. This seems safe because we run before the op. Link: http://lore.kernel.org/netdev/69b5ad67.a00a0220.3b25d1.001a.GAE@google.com Signed-off-by: Stanislav Fomichev --- net/core/rtnetlink.c | 1 + net/wireless/core.c | 1 + net/wireless/nl80211.c | 2 +- 3 files changed, 3 insertions(+), 1 deletion(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index dad4b1054955..b1bfb4a4aedd 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -150,6 +150,7 @@ void __rtnl_unlock(void) head = next; } } +EXPORT_SYMBOL_NS_GPL(__rtnl_unlock, "NETDEV_INTERNAL"); void rtnl_unlock(void) { diff --git a/net/wireless/core.c b/net/wireless/core.c index 23afc250bc10..a78a9b613c94 100644 --- a/net/wireless/core.c +++ b/net/wireless/core.c @@ -41,6 +41,7 @@ MODULE_AUTHOR("Johannes Berg"); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("wireless configuration support"); MODULE_ALIAS_GENL_FAMILY(NL80211_GENL_NAME); +MODULE_IMPORT_NS("NETDEV_INTERNAL"); /* RCU-protected (and RTNL for writers) */ LIST_HEAD(cfg80211_rdev_list); diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index e15cd26f3a79..f8ed8730cf1c 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -18203,7 +18203,7 @@ static int nl80211_pre_doit(const struct genl_split_ops *ops, __release(&rdev->wiphy.mtx); } if (!(internal_flags & NL80211_FLAG_NEED_RTNL)) - rtnl_unlock(); + __rtnl_unlock(); return 0; out_unlock: -- 2.53.0