From nobody Sat Oct 11 12:07:00 2025 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 68412286D6E for ; Tue, 10 Jun 2025 09:22:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749547324; cv=none; b=t3oH9vzO3DPgn0q58AaW95Nh6cF+abD605sUWJvIgYD7oE8ocUXmAut625713dsYC1462dsRx8LS5429HIzFwCoqtTjJ2qrjLs5uUbhk4jJ5VlHS34+ytPYmz1F9LBgTBX3UTfGhmlKyxSQabnaYuGjO5smMw7yp3KAKVisu6Yw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749547324; c=relaxed/simple; bh=YGXBP9lwMZfji91RKvnUA24jkXgM6whNm6o4hq7TUoM=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=GkHpiVZtK/0FNoIEh8m7un0pObFLeJnVCVzjcTVARL+12eVYor+QO/3ptaj1HAkfAx6Z1OdVgXR5/Izyt/vZ2RHHssvw+eJUjIdyiZTdViJaaFGfMJeVoYUadTWvMn4GWCXz6poM1IEgGNXpy3tTPs/nOTw0ubkHMfcJN6sU8KA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=svACTFx0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="svACTFx0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E9C35C4CEEF; Tue, 10 Jun 2025 09:22:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749547323; bh=YGXBP9lwMZfji91RKvnUA24jkXgM6whNm6o4hq7TUoM=; h=From:To:Cc:Subject:Date:From; b=svACTFx09ibq9oXJmJ5KtYYuSNq+csVKSuSUFl0u+XBinwGs078V0humsqDKKCwEX FjWoMA/LrI51XhkQ9JNaocFw3mfRzWRJAZeJy32EWwV4D1vcQ8pV1J92cCq5o5z8ta XFIOJuib7imHaaxDV6RjcHX1yYVfePRuf0M1PJueMiFN3oiJD8dWJ4rBb/W5JEAmls KpkMp2vWAY43Yn4RIRmBlGlaDfLwRFpD6b+FJQv8KCNGIoQYqI8up0qne7yaEiZBVC m5KCHidQ7h07//TeBMRQYOTL/3Nr7bHAfAf91sXjVaJkDu8679kn6gOqV8fKrWJRLu zHjDRTJY05IVA== From: Arnd Bergmann To: Andrew Morton , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= Cc: Arnd Bergmann , David Hildenbrand , Alistair Popple , Jason Gunthorpe , Thorsten Blum , Jeff Johnson , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] lib/test_hmm: reduce stack usage Date: Tue, 10 Jun 2025 11:21:50 +0200 Message-Id: <20250610092159.2639515-1-arnd@kernel.org> X-Mailer: git-send-email 2.39.5 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: Arnd Bergmann The various test ioctl handlers use arrays of 64 integers that add up to 1K= iB of stack data, which in turn leads to exceeding the warning limit in some configurations: lib/test_hmm.c:935:12: error: stack frame size (1408) exceeds limit (1280) = in 'dmirror_migrate_to_device' [-Werror,-Wframe-larger-than] Use half the size for these arrays, in order to stay under the warning limi= ts. The code can already deal with arbitrary lengths, but this may be a little = less efficient. Signed-off-by: Arnd Bergmann --- lib/test_hmm.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/lib/test_hmm.c b/lib/test_hmm.c index 5b144bc5c4ec..761725bc713c 100644 --- a/lib/test_hmm.c +++ b/lib/test_hmm.c @@ -330,7 +330,7 @@ static int dmirror_fault(struct dmirror *dmirror, unsig= ned long start, { struct mm_struct *mm =3D dmirror->notifier.mm; unsigned long addr; - unsigned long pfns[64]; + unsigned long pfns[32]; struct hmm_range range =3D { .notifier =3D &dmirror->notifier, .hmm_pfns =3D pfns, @@ -879,8 +879,8 @@ static int dmirror_migrate_to_system(struct dmirror *dm= irror, unsigned long size =3D cmd->npages << PAGE_SHIFT; struct mm_struct *mm =3D dmirror->notifier.mm; struct vm_area_struct *vma; - unsigned long src_pfns[64] =3D { 0 }; - unsigned long dst_pfns[64] =3D { 0 }; + unsigned long src_pfns[32] =3D { 0 }; + unsigned long dst_pfns[32] =3D { 0 }; struct migrate_vma args =3D { 0 }; unsigned long next; int ret; @@ -939,8 +939,8 @@ static int dmirror_migrate_to_device(struct dmirror *dm= irror, unsigned long size =3D cmd->npages << PAGE_SHIFT; struct mm_struct *mm =3D dmirror->notifier.mm; struct vm_area_struct *vma; - unsigned long src_pfns[64] =3D { 0 }; - unsigned long dst_pfns[64] =3D { 0 }; + unsigned long src_pfns[32] =3D { 0 }; + unsigned long dst_pfns[32] =3D { 0 }; struct dmirror_bounce bounce; struct migrate_vma args =3D { 0 }; unsigned long next; @@ -1144,8 +1144,8 @@ static int dmirror_snapshot(struct dmirror *dmirror, unsigned long size =3D cmd->npages << PAGE_SHIFT; unsigned long addr; unsigned long next; - unsigned long pfns[64]; - unsigned char perm[64]; + unsigned long pfns[32]; + unsigned char perm[32]; char __user *uptr; struct hmm_range range =3D { .hmm_pfns =3D pfns, --=20 2.39.5