From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) (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 D844040BCB6 for ; Fri, 10 Jul 2026 10:42:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783680164; cv=none; b=u+/KBJbIrN5tSA2DR4hZTb0bCM69TbrZO8W2VJphOrLacfNHa3qPbxizsKQKLYYuxB5x5TFKEhrChJabU9Fwz8r+VlMa8YWE7TnqJakN2Ang46kICyPGIuVdIV1gAkVkX0/TkhO48JYZeDtjN+UeuZYRUffw4L8K97uhAmnTgEY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783680164; c=relaxed/simple; bh=hvg2eIJW3W5IntN8hk1akDVckNcGwAcn6UofVGjU3eI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=WFEWaOWtzByHs1h7QagqYK4PdDJsumCjmwGX/XwlMF+plt5x3d2JDdBlQEMuqlTUUPkog6Is7lz0ZqWYmfMc+/2CKJnf1u1meHSRirm2JCvWoj8NyOX8L+8lF4+9Rhy3N91sVDqLA9gdbbsKSO6E+O35xf98XqJkRlFD6be+OuI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jackmanb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=dQg29Hbq; arc=none smtp.client-ip=209.85.128.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jackmanb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="dQg29Hbq" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-49244130073so6964085e9.1 for ; Fri, 10 Jul 2026 03:42:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1783680161; x=1784284961; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=fIBOMMuJQhrTdV+Tjmcx1KZT+n3b2t8dDXgjQ/32pgM=; b=dQg29HbqOS2hDj2Zyk29gwtZ0AfWc381B7nm9gAm0RQ1Br6zlSmRtoQL/PlJviKi4y 3Mob2ABBbYWYUw8xZdoO/uibqtRXookzc212bW46MryQKCNlnbO+VGV9FSAjPuLj7qBj y8VJRJ+j/KR4InmR7qK4M2oYpRbVJzGRweLG6dXPplftl9Cm8awigCR09ERwtirN9Uzp Hq2GfCODdPW3plrtoGgCx1+F4QxpOpyGzJvTJ/jLTaiayUUtHaiXE5OfTYAk7hTSiQHm /BKNMBhMHP/zdLs6Is6k31L//YxKcH4kRgMZTKp75g6A+1Y46IE1PX1kIPKmJrXUOP2D kNiw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783680161; x=1784284961; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=fIBOMMuJQhrTdV+Tjmcx1KZT+n3b2t8dDXgjQ/32pgM=; b=UuSn6xSsTJuXZUh0QP/K8AL6XzS7L/znqrKwlA85zx2yxO9K6UVj+W6K++gsH2oP31 stiuWFK5s8jbc8j4JzePh+t+aH+w+TF02PVN8IhjnvStXM3bLO0mNtgjkPkY0e82aV9X t9zWKCDefaoBdkE8URzzWC4DA21cvRWBn6Y6JKZClh/U4qge+6SSKbvhWnv3sAikD8rq RKgzaJTnRs+rbqCzLncbmo+69ehIbk5ubu/ViaDOfTlGcVLgFMZ+3ckGl1qo3jhdmnOu TvkXojqUD7fzWkwA/8jJWsGhqGhg+oyHDd+AsqyB2HAr+zi61Q8EQPfaCetwxS99HMDC maWA== X-Forwarded-Encrypted: i=1; AHgh+RrL0YdPSvqCMIuYEwKlj44d2Sw2tgUo+thAWW9sdYzuh66vt75gqLFDbK1X2y53Cq+4aZSMaFfdqhe49bM=@vger.kernel.org X-Gm-Message-State: AOJu0YwPCVw6WOkUmZb3pbM1r4lK2hzZP1zJWFfB6hoCwaMrykGqlfE8 XCWKMtqL0xPCGafRZz1bZA39lIARKUdZcUB0PdPEZoihKNORwPZyQmRh8kARIJpCvPM6U/wjS/w AAvA3ThMnvPCf4g== X-Received: from wmlz4.prod.google.com ([2002:a05:600c:2204:b0:492:1eeb:6111]) (user=jackmanb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:528e:b0:492:4363:e7eb with SMTP id 5b1f17b1804b1-493e68f03damr112833265e9.32.1783680161137; Fri, 10 Jul 2026 03:42:41 -0700 (PDT) Date: Fri, 10 Jul 2026 10:42:20 +0000 In-Reply-To: <20260710-spin-trylock-followup-v1-0-affb5fe5ed00@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260710-spin-trylock-followup-v1-0-affb5fe5ed00@google.com> X-Mailer: b4 0.15.2 Message-ID: <20260710-spin-trylock-followup-v1-1-affb5fe5ed00@google.com> Subject: [PATCH 1/2] mm/page_alloc: don't spin_trylock() in NMI on UP From: Brendan Jackman To: Andrew Morton , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Johannes Weiner , Zi Yan , Sebastian Andrzej Siewior , Clark Williams , Steven Rostedt , Shakeel Butt , Harry Yoo , Alexei Starovoitov Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Brendan Jackman , sashiko-bot@kernel.org, stable@vger.kernel.org Content-Type: text/plain; charset="utf-8" As noted in can_spin_trylock(), using this is unsafe in this context. commit 620b46ed6ae17 ("mm/page_alloc: return NULL early from alloc_frozen_pages_nolock() in NMI on UP") fixed this on the alloc side but missed the free side. Reported-by: sashiko-bot@kernel.org Link: https://sashiko.dev/#/patchset/20260703-alloc-trylock-v5-0-c87b714e19d3@google.com Cc: stable@vger.kernel.org Fixes: d7242af86434 ("mm: Introduce alloc_frozen_pages_nolock()") Signed-off-by: Brendan Jackman --- mm/page_alloc.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 9c97a86da2b9f..5fe1c11f919d7 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2979,8 +2979,7 @@ static void __free_frozen_pages(struct page *page, unsigned int order, migratetype = MIGRATE_MOVABLE; } - if (unlikely((fpi_flags & FPI_TRYLOCK) && IS_ENABLED(CONFIG_PREEMPT_RT) - && (in_nmi() || in_hardirq()))) { + if (unlikely((fpi_flags & FPI_TRYLOCK) && !can_spin_trylock())) { add_page_to_zone_llist(zone, page, order); return; } -- 2.54.0