From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 02C3639FC0 for ; Wed, 15 Nov 2023 20:44:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="TkvdKfMw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E7F3C433CB; Wed, 15 Nov 2023 20:44:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700081068; bh=+C2ptoDde7M6vmktO6AqBGHkWV2NylEXP9Rt0K2H2zI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TkvdKfMwrpKatx8vZ4mr6CZepyt4E1y9amikrzjUW4HQZe3cXSG80CRe4XbzcTVTy 99VAIOekBvIF1v1CpzYwTBGEPlaz4Y8gqX37UfwTpQunzWBfnpjlulDOSz3PtZU/Ws PAw0wtow6jtG4hzJO+v8T066RMc/NPSI+1ATXJnc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Wendy Wang , Chen Yu , Thomas Gleixner , Sasha Levin Subject: [PATCH 4.19 02/88] genirq/matrix: Exclude managed interrupts in irq_matrix_allocated() Date: Wed, 15 Nov 2023 15:35:14 -0500 Message-ID: <20231115191426.342160214@linuxfoundation.org> X-Mailer: git-send-email 2.42.1 In-Reply-To: <20231115191426.221330369@linuxfoundation.org> References: <20231115191426.221330369@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chen Yu [ Upstream commit a0b0bad10587ae2948a7c36ca4ffc206007fbcf3 ] When a CPU is about to be offlined, x86 validates that all active interrupts which are targeted to this CPU can be migrated to the remaining online CPUs. If not, the offline operation is aborted. The validation uses irq_matrix_allocated() to retrieve the number of vectors which are allocated on the outgoing CPU. The returned number of allocated vectors includes also vectors which are associated to managed interrupts. That's overaccounting because managed interrupts are: - not migrated when the affinity mask of the interrupt targets only the outgoing CPU - migrated to another CPU, but in that case the vector is already pre-allocated on the potential target CPUs and must not be taken into account. As a consequence the check whether the remaining online CPUs have enough capacity for migrating the allocated vectors from the outgoing CPU might fail incorrectly. Let irq_matrix_allocated() return only the number of allocated non-managed interrupts to make this validation check correct. [ tglx: Amend changelog and fixup kernel-doc comment ] Fixes: 2f75d9e1c905 ("genirq: Implement bitmap matrix allocator") Reported-by: Wendy Wang Signed-off-by: Chen Yu Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20231020072522.557846-1-yu.c.chen@intel.com Signed-off-by: Sasha Levin --- kernel/irq/matrix.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/irq/matrix.c b/kernel/irq/matrix.c index 8e586858bcf41..d25edbb87119f 100644 --- a/kernel/irq/matrix.c +++ b/kernel/irq/matrix.c @@ -466,16 +466,16 @@ unsigned int irq_matrix_reserved(struct irq_matrix *m) } /** - * irq_matrix_allocated - Get the number of allocated irqs on the local cpu + * irq_matrix_allocated - Get the number of allocated non-managed irqs on the local CPU * @m: Pointer to the matrix to search * - * This returns number of allocated irqs + * This returns number of allocated non-managed interrupts. */ unsigned int irq_matrix_allocated(struct irq_matrix *m) { struct cpumap *cm = this_cpu_ptr(m->maps); - return cm->allocated; + return cm->allocated - cm->managed_allocated; } #ifdef CONFIG_GENERIC_IRQ_DEBUGFS -- 2.42.0