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[94.134.180.43]) by smtp.gmail.com with ESMTPSA id l10sm6801522wmq.7.2021.12.29.07.33.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Dec 2021 07:33:44 -0800 (PST) From: Padmanabha Srinivasaiah To: linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Cc: gregkh@linuxfoundation.org, nsaenz@kernel.org, treasure4paddy@gmail.com, Stefan Wahren , Gaston Gonzalez , Ojaswin Mujoo , Arnd Bergmann , Phil Elwell , bcm-kernel-feedback-list@broadcom.com Subject: [PATCH] staging: vc04_services: Fix RCU dereference check Date: Wed, 29 Dec 2021 16:32:40 +0100 Message-Id: <20211229153243.6064-1-treasure4paddy@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In service_callback path RCU dereference done without rcu_read_[lock/unlock] pair, fixing same by using them. [ 32.201659] ============================= [ 32.201664] WARNING: suspicious RCU usage [ 32.201670] 5.15.11-rt24-v8+ #3 Not tainted [ 32.201680] ----------------------------- [ 32.201685] drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h:529 suspicious rcu_dereference_check() usage! [ 32.201695] [ 32.201695] other info that might help us debug this: [ 32.201695] [ 32.201700] [ 32.201700] rcu_scheduler_active = 2, debug_locks = 1 [ 32.201708] no locks held by vchiq-slot/0/98. [ 32.201715] [ 32.201715] stack backtrace: [ 32.201723] CPU: 1 PID: 98 Comm: vchiq-slot/0 Not tainted 5.15.11-rt24-v8+ #3 [ 32.201733] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT) [ 32.201739] Call trace: [ 32.201742] dump_backtrace+0x0/0x1b8 [ 32.201772] show_stack+0x20/0x30 [ 32.201784] dump_stack_lvl+0x8c/0xb8 [ 32.201799] dump_stack+0x18/0x34 [ 32.201808] lockdep_rcu_suspicious+0xe4/0xf8 [ 32.201817] service_callback+0x124/0x400 [ 32.201830] slot_handler_func+0xf60/0x1e20 [ 32.201839] kthread+0x19c/0x1a8 [ 32.201849] ret_from_fork+0x10/0x20 Signed-off-by: Padmanabha Srinivasaiah --- drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c index 6759a6261500..ee1b48db9681 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c @@ -1058,7 +1058,10 @@ service_callback(enum vchiq_reason reason, struct vchiq_header *header, DEBUG_TRACE(SERVICE_CALLBACK_LINE); + rcu_read_lock(); service = handle_to_service(handle); + rcu_read_unlock(); + if (WARN_ON(!service)) return VCHIQ_SUCCESS; -- 2.17.1