From nobody Thu Oct 2 09:19:15 2025 Received: from mail-qv1-f41.google.com (mail-qv1-f41.google.com [209.85.219.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2D83227AC57 for ; Fri, 19 Sep 2025 09:13:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.41 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758273184; cv=none; b=iSRp8mpn/bAzUezH8JjOBFnC49NrZz4NPLlwmpnxf+kF3WGWM4jL9OodwHuNR5wS5IUF1K6Ltjpxu9oflAbsO0Os0PgXlxiOEysXQeOtyBNtQQNUv43j0cKQhtc4wNiHrAcKWIJaWKGdmiCQJec9aMz8ccAFO9/qbRz+OsNGoK0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758273184; c=relaxed/simple; bh=QweTAqxNpSrDrK2q0/RR+kdBUV2hZvkvOnc1TJn8Yck=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NP2J82Rkj0tO8lDehiJYvtzT3DAXlcaShoaozrGnQRSxv8qv92eai9TxAWVL6wyc3lc/421PHBt2Aoy7w+yjQAtSQuBGNZ0+nZTAg+zG+st7AthcfQwHKsd9ionNm/8nIBIym1UqHeGFjuVp8FSbFqAJ5IB+NQcLVEc/3odDmWo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=hVPmUjVX; arc=none smtp.client-ip=209.85.219.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hVPmUjVX" Received: by mail-qv1-f41.google.com with SMTP id 6a1803df08f44-78ea15d3489so18630476d6.3 for ; Fri, 19 Sep 2025 02:13:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1758273182; x=1758877982; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:feedback-id:from:to:cc:subject :date:message-id:reply-to; bh=K70gfC2VGaXawlZrrSZ8hp0QF5eghAVmIXEzCCUkbN4=; b=hVPmUjVX8qD57Te8PtzQaXb7pzBCYUxYaT3AmPJBcIgvd1tDfMhYhZjEmMPWZiaLEN 91vtiIAhkGHfCFl0gV/2yFN/y23ek1ZjvYmsOIyib5wa461d8v6B7hIqdeRfNVMo+P23 yxeOnXtX2tf8EZY0MD3PPX1Fo8bSzHpE3FwLYB2xMWZtE6Lsxd/TDK0Gl89WBIgxs9Sn TWhY9zUmpV9cLSWB0mto1XtmyatUBIhboUcks0AaUhdIOCUI1tz5xI85IfAy0Gz+BN2J 7Emn7lx0c/fJHle5K9pQ8qnVkIrtQt/NLGZt4/Xw71tCkOLxetOZ7jxRC9sWaFRlwp+g /68A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758273182; x=1758877982; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:feedback-id:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=K70gfC2VGaXawlZrrSZ8hp0QF5eghAVmIXEzCCUkbN4=; b=A1x3nmVT99V4ADDC1SYTwY0VRVFsW0uWPErYZqJ59/Lj0fuZGTpSeR85RApJV4US+W cqydSkJ0T8SegTQ6a4/pm1uTsRr6BPOhKfmZjUfmFoNkdCU15f9HLyWcWtW8mepDb9YH alMBfpTMlwCRgiJJPk1WglndLp1ZdDh5u0UPtXmxPddd5eaOhlMG1Q9KqrRSs4+gfh9/ mqDNIwFVmacF7wiw4Jc/1kSDa5KjaVw/+gXyXoXYO4L2ES32uMAgaXDzOSyBcf9sHiPh o21fCYwgJ09mGAsFzQ+Hg57u1sMQgq3aAi3OwstjUKZHeFwJk7I7IlA+oWVZU4b2v8wr skQg== X-Forwarded-Encrypted: i=1; AJvYcCXEdWGJLjHw9kHW0Hvh1b07RKeAFga03u9WSYxqSpCE9S4WvzZ2TfXMYI1QUqdoi7pK8VQe2qFGqc2pC18=@vger.kernel.org X-Gm-Message-State: AOJu0YygZtUj/xRedROMpY8XQ+f6Hrh9KHwcIKkFQLOGp5y1lmAnsXn+ ojJjTxj45bAKdVSMrvUBkNla3kqpEvRDJBgmxJ+oc+GKxQoXkXd9loBO X-Gm-Gg: ASbGncsO4ctJ260FHe/lWDxva2UQJoJUJIjWNOylOICxABVY2eevfD915Gzs3LiWhDf EOLmrNNHj/CjkvMkst0dJ5Asx0739mG6kn5CMBFk87bD6UEa8tkVJ2fH2ot406x6QuTysOpzMK9 xWtkmzU4pn13IIsdU4F5ZcdwR/Ovb0Zm1TrPMo8sWW/SInHgNlh9eJdmeSLGzbLZC4T4IeXR92T G7T5be8Q+jXOHXYGETnklc2czksdb5LmqFzb1cNPUZmiEqUeYRikhRKJTnvM53+qOgzVmzj8DiY 4TuFDeoJSG/p3ZHJiGte24uLOKVqy5hFWZH64XJ8WmxBWMALMcEzrtpaBE5/9eKJG8M/NECEimt fiNeiThixWog6Gl290+Cn1jk4eHFmf3YuR9sNuy2w+4CmOWtfo19BfJSeCLRceBmCwhnTOshfdX ypVBY7uB7Yr0GZ X-Google-Smtp-Source: AGHT+IENO3y1I+WdQckOF9/GGnaAMQ+ul1aKo9ejx3/ulS4DRfGqgjIdtHE0clXgDs5HZit1Tjxilw== X-Received: by 2002:a05:6214:29e1:b0:794:6621:6d18 with SMTP id 6a1803df08f44-7991d549c82mr24827026d6.51.1758273182126; Fri, 19 Sep 2025 02:13:02 -0700 (PDT) Received: from fauth-a2-smtp.messagingengine.com (fauth-a2-smtp.messagingengine.com. [103.168.172.201]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-793474ac8dasm26073756d6.30.2025.09.19.02.13.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Sep 2025 02:13:01 -0700 (PDT) Received: from phl-compute-12.internal (phl-compute-12.internal [10.202.2.52]) by mailfauth.phl.internal (Postfix) with ESMTP id 3316AF40066; Fri, 19 Sep 2025 05:13:01 -0400 (EDT) Received: from phl-mailfrontend-01 ([10.202.2.162]) by phl-compute-12.internal (MEProxy); Fri, 19 Sep 2025 05:13:01 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtdeggdegkeekvdcutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpuffrtefokffrpgfnqfghnecuuegr ihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjug hrpefhvfevufffkffojghfggfgsedtkeertdertddtnecuhfhrohhmpeeuohhquhhnucfh vghnghcuoegsohhquhhnrdhfvghnghesghhmrghilhdrtghomheqnecuggftrfgrthhtvg hrnhepgffhffevhffhvdfgjefgkedvlefgkeegveeuheelhfeivdegffejgfetuefgheei necuffhomhgrihhnpehkvghrnhgvlhdrohhrghenucevlhhushhtvghrufhiiigvpedtne curfgrrhgrmhepmhgrihhlfhhrohhmpegsohhquhhnodhmvghsmhhtphgruhhthhhpvghr shhonhgrlhhithihqdeiledvgeehtdeigedqudejjeekheehhedvqdgsohhquhhnrdhfvg hngheppehgmhgrihhlrdgtohhmsehfihigmhgvrdhnrghmvgdpnhgspghrtghpthhtohep vdefpdhmohguvgepshhmthhpohhuthdprhgtphhtthhopehpvghtvghriiesnhhfrhgrug gvrggurdhorhhgpdhrtghpthhtohepmhhinhhgoheskhgvrhhnvghlrdhorhhgpdhrtghp thhtohepthhglhigsehlihhnuhhtrhhonhhigidruggvpdhrtghpthhtoheprhhushhtqd hfohhrqdhlihhnuhigsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhi nhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplh hkmhhmsehlihhsthhsrdhlihhnuhigrdguvghvpdhrtghpthhtohepfihilhhlsehkvghr nhgvlhdrohhrghdprhgtphhtthhopehpvghtvghriiesihhnfhhrrgguvggrugdrohhrgh dprhgtphhtthhopehlohhnghhmrghnsehrvgguhhgrthdrtghomh X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 19 Sep 2025 05:13:00 -0400 (EDT) From: Boqun Feng To: "Peter Zijlstra" , "Ingo Molnar" , "Thomas Gleixner" Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, lkmm@lists.linux.dev, "Will Deacon" , "Peter Zijlstra" , Waiman Long , "Miguel Ojeda" , alex.gaynor@gmail.com, "Gary Guo" , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , "Benno Lossin" , "Alice Ryhl" , "Trevor Gross" , "Danilo Krummrich" , "Andreas Hindborg" , Alexander Sverdlin , stable@vger.kernel.org, Adrian Freihofer , "Paul E. McKenney" , Boqun Feng Subject: [PATCH 1/4] locking/spinlock/debug: Fix data-race in do_raw_write_lock Date: Fri, 19 Sep 2025 11:12:38 +0200 Message-ID: <20250919091241.32138-2-boqun.feng@gmail.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250919091241.32138-1-boqun.feng@gmail.com> References: <20250919091241.32138-1-boqun.feng@gmail.com> 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" From: Alexander Sverdlin KCSAN reports: BUG: KCSAN: data-race in do_raw_write_lock / do_raw_write_lock write (marked) to 0xffff800009cf504c of 4 bytes by task 1102 on cpu 1: do_raw_write_lock+0x120/0x204 _raw_write_lock_irq do_exit call_usermodehelper_exec_async ret_from_fork read to 0xffff800009cf504c of 4 bytes by task 1103 on cpu 0: do_raw_write_lock+0x88/0x204 _raw_write_lock_irq do_exit call_usermodehelper_exec_async ret_from_fork value changed: 0xffffffff -> 0x00000001 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 1103 Comm: kworker/u4:1 6.1.111 Commit 1a365e822372 ("locking/spinlock/debug: Fix various data races") has adressed most of these races, but seems to be not consistent/not complete. From do_raw_write_lock() only debug_write_lock_after() part has been converted to WRITE_ONCE(), but not debug_write_lock_before() part. Do it now. Cc: stable@vger.kernel.org Fixes: 1a365e822372 ("locking/spinlock/debug: Fix various data races") Reported-by: Adrian Freihofer Acked-by: Waiman Long Signed-off-by: Alexander Sverdlin Reviewed-by: Paul E. McKenney Signed-off-by: Boqun Feng --- Notes: SubmissionLink: https://lore.kernel.org/all/20250826102731.52507-1-alex= ander.sverdlin@siemens.com/ kernel/locking/spinlock_debug.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/locking/spinlock_debug.c b/kernel/locking/spinlock_debu= g.c index 87b03d2e41db..2338b3adfb55 100644 --- a/kernel/locking/spinlock_debug.c +++ b/kernel/locking/spinlock_debug.c @@ -184,8 +184,8 @@ void do_raw_read_unlock(rwlock_t *lock) static inline void debug_write_lock_before(rwlock_t *lock) { RWLOCK_BUG_ON(lock->magic !=3D RWLOCK_MAGIC, lock, "bad magic"); - RWLOCK_BUG_ON(lock->owner =3D=3D current, lock, "recursion"); - RWLOCK_BUG_ON(lock->owner_cpu =3D=3D raw_smp_processor_id(), + RWLOCK_BUG_ON(READ_ONCE(lock->owner) =3D=3D current, lock, "recursion"); + RWLOCK_BUG_ON(READ_ONCE(lock->owner_cpu) =3D=3D raw_smp_processor_id(), lock, "cpu recursion"); } =20 --=20 2.51.0