From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.128.42 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792646241; b=YMSEGMzi+uzojTtaUacTWcD4yza/m89IszkFr3T8o70pa5IOCYKBJJ8//BJ6xjpHxkvO YHQ8tWBzC7OPg9E2CdAkXkGe5u60KDm7ROalXg/AEwFW1i+ClRHtSToT82JWEVtTxV/D9 sHc9bjVkr0N1q6A610TcPJNtk1sa7+HRMJs4+P3R08doAU/1YxzAvyQC0zgZZ3VTkskUA tKew4JWYJRwilxwWfb8IDnrGW6pFz1jlyHLYM4aK13G1pJ55yRErXOk7uMVyft0G0aiCG mXvvAGEU6r/R/m7fNY/axPX3G4Wh8spCgU8R312fWJdmwMVs8WGqTXPguY6Ty4ZTb5Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792646241; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: From:To:Cc:Subject:Date:Message-Id:X-Mailer:In-Reply-To:References: MIME-Version:Content-Transfer-Encoding; bh=FHADbTy4zikl0HljBSmGkN/GzMWvpwiot6dr8kUaUas=; b=qFT9LFsB/n269cHstVl/wWmxiFQlGxnrlRevHjhOhe6P+E4V9pOpcihg1vtYa3qNcHrX srDrMp2Ri5W6gPgji/vZrU5mD+yMTtUL3VH/YoW1ietpxcWJwXtxoTns5bf6icIfy4/2r kwFfNJSr3ZBefISd04DfapUVKjTbCXRUH8YlzN+SA+orlOO5WHwpCsjaZmI0V8NtVJCaJ +fMuEwT5J3ZRFWtUXhwInFflRgQtoqT4E3KluZHEtv/Rpdm9xBpFGmV1dFFHzJXg9Zt5w jBijFEr0Fkk6fsXXpZMKx2A9YMjiWzf6KGZpr3LeuexaLntw5UeB0WQLiHvYCCd4W5Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20251104 header.b=GJ8MVNqh; arc=none smtp.remote-ip=209.85.128.42 Received: from mail-wm1-f42.google.com (mail-wm1-f42.google.com [209.85.128.42]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CCCD360A2607 for ; Thu, 22 Oct 2026 05:17:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org CCCD360A2607 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, unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20251104 header.b=GJ8MVNqh Received: by mail-wm1-f42.google.com with SMTP id 5b1f17b1804b1-4a1df4c0966so2693665e9.1 for ; Wed, 21 Oct 2026 22:17:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1792646239; x=1793251039; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=FHADbTy4zikl0HljBSmGkN/GzMWvpwiot6dr8kUaUas=; b=GJ8MVNqhnRrntr8SgM6UXidafF9eU+ZQd0Vc/ExGUloc15ICieAVftx4JAH7vssIeT gpv1uP2i99q9zJ7GxU1h5yYfKyuzVcFR7Pf5JBSLyLK829+VLlQ12Z7kIXurKA4HG4ss osOi8laCeLfIQtlnhFnufp/2cCQIsFivtIAPydAIib6/CYQSsgoilMYGcNVyRFWISaqG dzpiVJwT8C8qKYJuoSEyx5NflmKu369uj7BXTlEhpeqeV/LD+TqcsWtCVBIxlPNVIajX 19LhZq/cRLgIIj8i7ZTD3NJvMpJClkpLPaeViTVwH6vouvhThL2rGV3cGBO7lTEyIHKV K6jQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1792646239; x=1793251039; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=FHADbTy4zikl0HljBSmGkN/GzMWvpwiot6dr8kUaUas=; b=lzOgV6/mtp8S/FYTvdwBs7kQud8StfExUP3A6nKqmo3jkikf1SCa4F0uvp1TN+j1g2 JLr6c8IbZ6PqbjbmY285EvZTZs7pU277Nep4Zmso9bFUZAGL+TBqpN7rE1WixsoZLZ2z 9TcG+/dTrULLAe1zA2ZPvCQPz1uGfZJpvOOLCaryJ9H0+co4Mr5d/0ksceqcjCnVC/uI pRb2okTeWjYUQfuYQcp3VLkaTkXNtJ7Ucu5hgk8yPzNRLJjlEGMIyAq6w15Xf35jnH7B M5aEcLn2wkDEcvKUBhHzfmIVzllmuHxmirGVv4TU31mE60iQia1mG3VpqZpB2PhIOkSD w9jA== X-Forwarded-Encrypted: i=1; AKwUvBwPUbSW4mMBS0MGBdtvVx666v4UIEhSD9hlxQOrxhDw9ZiOM3zkosfLQRNqtJl4326oS5X8K3IK9SMTomz1TeIF4iE=@vger.kernel.org X-Gm-Message-State: AFq9FYKKDTVmdUxxsvhdymqhjULSgZkX9nLJu6bOXcNyl5PKMrDhP6eq VEh7eTFdLt4Rg06ghu7oOk4ZETyCFYShrEswlTEB4YXT85MIa8nC7slT X-Gm-Gg: AYBFou2zXaXl+JpFXITXEbN6ycHMOyalj4rei9nUY0B4leRgyYmD3aasJhx7VXZPZyV tI758T5YNH6fpUy3+XQGsUC7ho51pIDmThdI6pR7ByzlPoPn1GZJ/eO5rKbkhCzF30lLhTyShvv M40I3oAs7HsNk3XC8+wPUTjys7R5wDLv6qHJzftMSejbU99+k5wEV7Ldj0DJ3RrTxgrNs2/nG7i UPu0GlK4+UmU8eoD2tEEZj+UkLG4zVBXIoL5dgMrZSZ8/3q7ohoJbppyOG4AjVQSQ32PQXpNGHr B8C+GeFG9LbF+7Sxw9BwfiLgf9Pknffmt1krYYBv2BMrqtOzelcIP3wBTc0KPoa77Izv2IEnmn5 egil1LkKd0ShBpr24mOTDjBv44azrHqjpNt/ekSAC6GvzrY/h365tXLmEFqR+5K4XpC1IF+jhdM BKrpbORa4S1wf/Kwu5ej/YxkdCxWN5jlSdlY62fNcj2ARbT4PcUX6iC4ZhbG4dZPE9U04EhQ/5M uKHp8aFuOsoBElHCQq05KquD1pYQHySNDU7I7cChdsmu1YdEvwpWctlcPl+/KlL93uD8c6IWHpN eTDlpKOI6uKbYgiZok79yu36hRSmnLC2Rtq06S0/DcP3krd6Ii5ybjnXeIbk5AF3mxBWyB5qMj9 +CiMZcmAC3+SUKULVMKt2xalGb5p3Qzmp0+tvDJxIm5CxUyuys2dKh7+cDeU= X-Received: by 2002:a05:600c:4fc9:b0:4a1:efbe:529c with SMTP id 5b1f17b1804b1-4a204b2032cmr26718835e9.12.1792646239093; Wed, 21 Oct 2026 22:17:19 -0700 (PDT) Received: from localhost.localdomain (dynamic-2a02-3100-ad43-d501-2c28-bb72-120d-420e.310.pool.telefonica.de. [2a02:3100:ad43:d501:2c28:bb72:120d:420e]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a1fd0f4427sm90362275e9.3.2026.10.21.22.17.16 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 21 Oct 2026 22:17:18 -0700 (PDT) From: Karl Mehltretter To: Steven Rostedt , Peter Zijlstra , Thomas Gleixner Cc: Karl Mehltretter , Catalin Marinas , Will Deacon , Mark Rutland , Ingo Molnar , Andy Lutomirski , Frederic Weisbecker , "Paul E . McKenney" , Sebastian Andrzej Siewior , Boqun Feng , Waiman Long , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Hongyan Xia , Jonathan Corbet , Shuah Khan , Randy Dunlap , Andrew Morton , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , linux-arm-kernel@lists.infradead.org, linux-trace-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, linux-doc@vger.kernel.org, llvm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [RFC PATCH 02/12] lockdep: Use raw access for pinned hardirq state Date: Thu, 22 Oct 2026 07:16:44 +0200 Message-Id: <20261022051654.79224-3-kmehltretter@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) In-Reply-To: <20261022051654.79224-1-kmehltretter@gmail.com> References: <20261022051654.79224-1-kmehltretter@gmail.com> X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit irqentry_nmi_enter() reads lockdep's hardirq state before __nmi_enter() establishes NMI context. Arm64 does the same for its NMI-like EL1 debug entry. Both paths run with interrupts disabled and cannot migrate. lockdep_hardirqs_enabled() uses this_cpu_read(), whose preemption checks are unnecessary for these callers. Add a raw accessor and use it in the two entry paths and in lockdep_hardirqs_off(). Keep the existing accessor for callers which are not already pinned. Check the interrupt state before accessing per-CPU state in lockdep_hardirqs_off(), independently of warning suppression. On arm64, this change does not by itself make the call chain noinstr-safe: __kern_my_cpu_offset() must also be forced inline. That prerequisite is listed in the cover letter. Assisted-by: LLM --- arch/arm64/kernel/entry-common.c | 2 +- include/linux/irqflags.h | 3 +++ kernel/entry/common.c | 2 +- kernel/locking/lockdep.c | 6 ++++-- 4 files changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index 72c03ccea59fe..93056a766fb20 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -141,7 +141,7 @@ static noinstr irqentry_state_t arm64_enter_el1_dbg(struct pt_regs *regs) { irqentry_state_t state; - state.lockdep = lockdep_hardirqs_enabled(); + state.lockdep = lockdep_hardirqs_enabled_raw(); lockdep_hardirqs_off(CALLER_ADDR0); ct_nmi_enter(); diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h index 57b074e0cfbbb..5bc179a88e513 100644 --- a/include/linux/irqflags.h +++ b/include/linux/irqflags.h @@ -52,6 +52,8 @@ extern void trace_hardirqs_off(void); # define lockdep_hardirq_context() (raw_cpu_read(hardirq_context)) # define lockdep_softirq_context(p) ((p)->softirq_context) # define lockdep_hardirqs_enabled() (this_cpu_read(hardirqs_enabled)) +/* The caller must already be pinned to the current CPU. */ +# define lockdep_hardirqs_enabled_raw() (raw_cpu_read(hardirqs_enabled)) # define lockdep_softirqs_enabled(p) ((p)->softirqs_enabled) # define lockdep_hardirq_enter() \ do { \ @@ -113,6 +115,7 @@ do { \ # define lockdep_hardirq_context() 0 # define lockdep_softirq_context(p) 0 # define lockdep_hardirqs_enabled() 0 +# define lockdep_hardirqs_enabled_raw() 0 # define lockdep_softirqs_enabled(p) 0 # define lockdep_hardirq_enter() do { } while (0) # define lockdep_hardirq_threaded() do { } while (0) diff --git a/kernel/entry/common.c b/kernel/entry/common.c index e3d381fd3d251..28399c41ebfb1 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -171,7 +171,7 @@ irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs) { irqentry_state_t irq_state; - irq_state.lockdep = lockdep_hardirqs_enabled(); + irq_state.lockdep = lockdep_hardirqs_enabled_raw(); __nmi_enter(); lockdep_hardirqs_off(CALLER_ADDR0); diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index c3dc84a7cef26..01dba8fb32a90 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4543,10 +4543,12 @@ void noinstr lockdep_hardirqs_off(unsigned long ip) * So we're supposed to get called after you mask local IRQs, but for * some reason the hardware doesn't quite think you did a proper job. */ - if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) + if (unlikely(!irqs_disabled())) { + DEBUG_LOCKS_WARN_ON(1); return; + } - if (lockdep_hardirqs_enabled()) { + if (lockdep_hardirqs_enabled_raw()) { struct irqtrace_events *trace = ¤t->irqtrace; /* -- 2.39.5 (Apple Git-154)