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[76.102.12.149]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-129b413930esm3529158c88.13.2026.03.18.08.03.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Mar 2026 08:03:09 -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, 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 v2 02/13] wifi: cfg80211: use __rtnl_unlock in nl80211_pre_doit Date: Wed, 18 Mar 2026 08:02:54 -0700 Message-ID: <20260318150305.123900-3-sdf@fomichev.me> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260318150305.123900-1-sdf@fomichev.me> References: <20260318150305.123900-1-sdf@fomichev.me> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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@googl= e.com Signed-off-by: Stanislav Fomichev Reviewed-by: Aleksandr Loktionov --- net/wireless/nl80211.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 2225f5d0b124..ce5f25d4c87e 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -18192,7 +18192,7 @@ 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(); =20 return 0; out_unlock: --=20 2.53.0