From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 328AE29A31C for ; Tue, 11 Aug 2026 04:17:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786421842; cv=none; b=SqCT1FKr3ajfZGi8d9bBxl0SmNOTIaCOpPfwq67Awpdq4yNtFhNwD3jYhd7AZ0UWlRW2NSkXtOEpFUn/wD//pcC4ODslydyhMRQo8Y5I2Fni82yPybcejJwWj+xjKFSIe/U2toAN916Zfq8JenpYo3H21MFCQ4NAC64bHzdwixQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786421842; c=relaxed/simple; bh=r+2NyJ+8cLw/gTrq7CrMO+BUfJ0zEFGOC0qQx6gO4Rw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TsWAEkfuh6L5iYboZcuDjIrwqVpdwfHL7Bk6Hk5JtOgLUFxi7PmLT7fD4brbs2xMvGUJs0KOgQ0gcIAL9E3NJb11K4F1FdRnC7OGGTLy3HlJ2mfw3SD5jD/Vo1UIfFY+ws2p0Gy601zaCjGufaRCkT2aT9SnN6yYeoZYgOc3xGk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mxu2/5pM; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mxu2/5pM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 70B121F00A3D; Tue, 11 Aug 2026 04:17:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786421841; bh=GFTRh8K9ao1Em0M3ZaR9f6KuHfXT+zHCDFY51R1n7EA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mxu2/5pMT5aNxFe8VwJQeQdLFYwvB/3fI6F+3TB36VwUnthpmibWrxOUnExUeVCd0 1PY2RHBpTgMkFcmNRkbuePVM5vZ0Y3ozLiek0ISKWQmzah7pFMUX9a5yNQAzJXagfw 5PMBoidg7pA0b4ldd+hqmwngoc7alLocXkPeX3j+9atm3LSOrF+j1SzOPG3H1TGJRI 9MmWkNoolsCFXez2TJll665T1DFE1hsUVYVfeocCQZxHLFsjjQ60JU9oC4oSZ1oEf9 Vueqaeu17TWDpDc5XeXdmRXbo2YJsEqYWd6KLIBME6KoC+BCYy79SIopDS6xy/+JDd /QJRjlfD97vSw== Received: from phl-compute-03.internal (phl-compute-03.internal [10.202.2.43]) by mailfauth.phl.internal (Postfix) with ESMTP id AF1EFF40067; Tue, 11 Aug 2026 00:17:19 -0400 (EDT) Received: from phl-frontend-03 ([10.202.2.162]) by phl-compute-03.internal (MEProxy); Tue, 11 Aug 2026 00:17:19 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: dmFkZTFcHzrhXyc0hnypovlJb9g9E7tJfxSxtSmVOni2o4Z0btOd3O0kXf/OsfEdeTwWWt sfbUizPnOdS26Htcmx9apVGOWKxWk+wwPpxYEq9frjxZ2FxQpco5+ZZwomcL9FwE9d4fNS oevDjxTnIiU7+zHZiay/54MDECaPVHjwLyS96w/B5Sn5DGoooChP5NgFUVVKEJyxwN28Um Ld6gWozLgvLzSJiV+a9p+OUuLs0I2bwZeWF4Y3dMuFZzemOg9WiRd/K0zK3J4CSVSOPd27 hphNIVrkXD5dt0hYBf2mNvHC0T9otlvMegJU45fh9pbloduDE6zLHpprgijfzk0RgrW3EG s0D5z6LlJDQWGINj/hUk4CXmbrv6s/dueEgSE8JYNuP/i34JxmgwFmt4M+Dew3e9qvaMUj qp1rCttBy9pSa1WsfKy2CjQmgsHg8BsgaPF00laQDH6rGhYiuy2XeiZOFo9BpQl2fqtLRW o/00xSzKrzloC75dkMkegayXS6aAH+Y8BoEPMrSD71NqBQz3DePn+Zb1qpT4ETVi7Gz7YT 1f3KD9hdRKcMy4l/oJ6ceCdIkXkVBC1d7pfAqHLNyO0MDPtb/AXMYcFwHjGztOOj/8gVqp 3Zla1LFvQ+kPpLa5WPrn/hRGhuZ1Z3fZCJGrmbcLccq/0OaBZBwViRuI2B2g X-ME-Proxy: Feedback-ID: i8dbe485b:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 11 Aug 2026 00:17:19 -0400 (EDT) From: Boqun Feng To: Peter Zijlstra Cc: "Ingo Molnar" , "Will Deacon" , "Boqun Feng" , "Waiman Long" , "Gary Guo" , "Alice Ryhl" , "Lyude Paul" , "Daniel Almeida" , =?UTF-8?q?Onur=20=C3=96zkan?= , "Miguel Ojeda" , "Danilo Krummrich" , linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, Shrikanth Hegde Subject: [PATCH 1/4] irq: Add {over,under}flow detection for local_interrupt_{enable,disable} Date: Mon, 10 Aug 2026 21:17:11 -0700 Message-ID: <20260811041714.27679-2-boqun@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260811041714.27679-1-boqun@kernel.org> References: <20260810085255.GE1642880@noisy.programming.kicks-ass.net> <20260811041714.27679-1-boqun@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Currently there is no way to detect overflow and underflow inside the HARDIRQ_DISABLE_MASK part of preempt_count. Add these detection guarded by DEBUG_PREEMPT similar to the detection for PREEMPT_MASK {over,under}flow. Suggested-by: Shrikanth Hegde Signed-off-by: Boqun Feng --- include/linux/interrupt_rc.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/include/linux/interrupt_rc.h b/include/linux/interrupt_rc.h index b9a7f05ecf42..e2456500a646 100644 --- a/include/linux/interrupt_rc.h +++ b/include/linux/interrupt_rc.h @@ -11,6 +11,7 @@ * make it easier to include without hitting circular header dependencies. */ +#include #include #include #include @@ -63,6 +64,13 @@ static inline void local_interrupt_disable(void) new_count = hardirq_disable_enter(); + /* Is hardirq disable count overflow soon? */ + if (IS_ENABLED(CONFIG_DEBUG_PREEMPT) && + DEBUG_LOCKS_WARN_ON(((new_count & HARDIRQ_DISABLE_MASK) + + (10 << HARDIRQ_DISABLE_SHIFT)) >= + HARDIRQ_DISABLE_MASK)) + return; + /* Interrupts can happen here, but it's OK, see __irq_exit_rcu(). */ if ((new_count & HARDIRQ_DISABLE_MASK) == HARDIRQ_DISABLE_OFFSET) @@ -73,6 +81,11 @@ static inline void local_interrupt_enable(void) { int new_count; + /* Unpaired local_interrupt_enable()? Warn and abort. */ + if (IS_ENABLED(CONFIG_DEBUG_PREEMPT) && + DEBUG_LOCKS_WARN_ON((preempt_count() & HARDIRQ_DISABLE_MASK) == 0)) + return; + new_count = hardirq_disable_exit(); if ((new_count & HARDIRQ_DISABLE_MASK) == 0) -- 2.50.1 (Apple Git-155)