From nobody Sun Feb 8 09:13:05 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 391A71494DB for ; Sun, 21 Dec 2025 08:58:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766307510; cv=none; b=iRq0ZNOu/d5NF9+nlBEroGawrZGJ5b+DMxgZG4cojZHvU4+rrzfLHIuCRtdMlScL3l8lLyzp44MonuruX324+5MxaJHo7YYnEX49F76vWjDeyx+iyRw95sm/TwOQ1V4qY5kqvvmemHtOCoHbYU73v55bp+lZFlpWJORjY41Nezk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766307510; c=relaxed/simple; bh=o+tUNFsOPBKIzPT9dgU1YaSzNI6zIu1kIaWgdAmDLh4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NWkFAwtevHenivrHdZhQmQiLhcb+FUvpz6vUBdmGrlH/H9ZA51qpHjEu2jWwtKN0Fk62mji5TiYjoWi7c6oZlQ0PhlzcbiVI9c2OlWlWBcRi+yqJyuSb0FPedgREzt5aNdQmfzTdceh6OzvoJlcO6ImdYaQ3iL+am5bMPiatJTs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=BJl5EHpr; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BJl5EHpr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1766307508; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tSork19nHW6YKdr7H91m897S5X3FouxxKb6TE2rVX6g=; b=BJl5EHpreM87NHRmMcHAQExT8befVUH5kWxY+7Rn3UdU42F/f2L5k9k0GMQ0H2rd06w24p jkW19tGs+I6vhgtDDTdLEq4MYxmm30Zhy71l5OMFz5ITFlYc4dYdDP1Wwkkb5teOwwJ2QV BHK+Y7Wew+ItbACJWA/6RNKLSl3a/AQ= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-253-85XfBGhFNiSN_qbv9wHraw-1; Sun, 21 Dec 2025 03:58:24 -0500 X-MC-Unique: 85XfBGhFNiSN_qbv9wHraw-1 X-Mimecast-MFC-AGG-ID: 85XfBGhFNiSN_qbv9wHraw_1766307502 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7C2B6195608A; Sun, 21 Dec 2025 08:58:22 +0000 (UTC) Received: from dell-per7425-02.rhts.eng.pek2.redhat.com (dell-per7425-02.rhts.eng.pek2.redhat.com [10.73.116.18]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A1DA430001A2; Sun, 21 Dec 2025 08:58:18 +0000 (UTC) From: Li Wang To: akpm@linux-foundation.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: David Hildenbrand , Mark Brown , Shuah Khan , Waiman Long Subject: [PATCH v2 1/3] selftests/mm/write_to_hugetlbfs: parse -s as size_t Date: Sun, 21 Dec 2025 16:58:08 +0800 Message-ID: <20251221085810.3163919-2-liwang@redhat.com> In-Reply-To: <20251221085810.3163919-1-liwang@redhat.com> References: <20251221085810.3163919-1-liwang@redhat.com> 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 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Content-Type: text/plain; charset="utf-8" write_to_hugetlbfs currently parses the -s size argument with atoi() into an int. This silently accepts malformed input, cannot report overflow, and can truncate large sizes. Acked-by: David Hildenbrand (Red Hat) --- Error log --- # uname -r 6.12.0-xxx.el10.aarch64+64k # ls /sys/kernel/mm/hugepages/hugepages-* hugepages-16777216kB/ hugepages-2048kB/ hugepages-524288kB/ #./charge_reserved_hugetlb.sh -cgroup-v2 # ----------------------------------------- ... # nr hugepages =3D 10 # writing cgroup limit: 5368709120 # writing reseravation limit: 5368709120 ... # Writing to this path: /mnt/huge/test # Writing this size: -1610612736 <-------- Switch the size variable to size_t and parse -s with sscanf("%zu", ...). Also print the size using %zu. This avoids incorrect behavior with large -s values and makes the utility more robust. Signed-off-by: Li Wang Cc: David Hildenbrand Cc: Mark Brown Cc: Shuah Khan Cc: Waiman Long --- tools/testing/selftests/mm/write_to_hugetlbfs.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/mm/write_to_hugetlbfs.c b/tools/testin= g/selftests/mm/write_to_hugetlbfs.c index 34c91f7e6128..ecb5f7619960 100644 --- a/tools/testing/selftests/mm/write_to_hugetlbfs.c +++ b/tools/testing/selftests/mm/write_to_hugetlbfs.c @@ -68,7 +68,7 @@ int main(int argc, char **argv) int key =3D 0; int *ptr =3D NULL; int c =3D 0; - int size =3D 0; + size_t size =3D 0; char path[256] =3D ""; enum method method =3D MAX_METHOD; int want_sleep =3D 0, private =3D 0; @@ -86,7 +86,10 @@ int main(int argc, char **argv) while ((c =3D getopt(argc, argv, "s:p:m:owlrn")) !=3D -1) { switch (c) { case 's': - size =3D atoi(optarg); + if (sscanf(optarg, "%zu", &size) !=3D 1) { + perror("Invalid -s."); + exit_usage(); + } break; case 'p': strncpy(path, optarg, sizeof(path) - 1); @@ -131,7 +134,7 @@ int main(int argc, char **argv) } =20 if (size !=3D 0) { - printf("Writing this size: %d\n", size); + printf("Writing this size: %zu\n", size); } else { errno =3D EINVAL; perror("size not found"); --=20 2.49.0 From nobody Sun Feb 8 09:13:05 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 A281D1494DB for ; Sun, 21 Dec 2025 08:58:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766307516; cv=none; b=NfS923H1tREAXYjGMwliPCRwEASVlMmEcTDuf9UcFiTlIQnXqkwrg4vsYcOx6699C8kQtLCKmaabbnU0EFHGQe3lD9+pTHONtPrSrgfb08tGwP4lNggASJA933plr/Zaul+4sLtnPcIUyh6WlNOm5hzmqvIyyMHX52eP58d+G4g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; 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Sun, 21 Dec 2025 08:58:26 +0000 (UTC) Received: from dell-per7425-02.rhts.eng.pek2.redhat.com (dell-per7425-02.rhts.eng.pek2.redhat.com [10.73.116.18]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 28FFF30001A2; Sun, 21 Dec 2025 08:58:22 +0000 (UTC) From: Li Wang To: akpm@linux-foundation.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: David Hildenbrand , Mark Brown , Shuah Khan , Waiman Long Subject: [PATCH v2 2/3] selftests/mm/charge_reserved_hugetlb.sh: add waits with timeout helper Date: Sun, 21 Dec 2025 16:58:09 +0800 Message-ID: <20251221085810.3163919-3-liwang@redhat.com> In-Reply-To: <20251221085810.3163919-1-liwang@redhat.com> References: <20251221085810.3163919-1-liwang@redhat.com> 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 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Content-Type: text/plain; charset="utf-8" The hugetlb cgroup usage wait loops in charge_reserved_hugetlb.sh were unbounded and could hang forever if the expected cgroup file value never appears (e.g. due to bugs, timing issues, or unexpected behavior). --- Error log --- # uname -r 6.12.0-xxx.el10.aarch64+64k # ls /sys/kernel/mm/hugepages/hugepages-* hugepages-16777216kB/ hugepages-2048kB/ hugepages-524288kB/ #./charge_reserved_hugetlb.sh -cgroup-v2 # ----------------------------------------- ... # nr hugepages =3D 10 # writing cgroup limit: 5368709120 # writing reseravation limit: 5368709120 ... # write_to_hugetlbfs: Error mapping the file: Cannot allocate memory # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 ... Introduce a small helper, wait_for_file_value(), and use it for: - waiting for reservation usage to drop to 0, - waiting for reservation usage to reach a given size, - waiting for fault usage to reach a given size. This makes the waits consistent and adds a hard timeout (120 tries with 0.5s sleep) so the test fails instead of stalling indefinitely. Signed-off-by: Li Wang Cc: David Hildenbrand Cc: Mark Brown Cc: Shuah Khan Cc: Waiman Long --- .../selftests/mm/charge_reserved_hugetlb.sh | 47 ++++++++++--------- 1 file changed, 26 insertions(+), 21 deletions(-) diff --git a/tools/testing/selftests/mm/charge_reserved_hugetlb.sh b/tools/= testing/selftests/mm/charge_reserved_hugetlb.sh index e1fe16bcbbe8..249a5776c074 100755 --- a/tools/testing/selftests/mm/charge_reserved_hugetlb.sh +++ b/tools/testing/selftests/mm/charge_reserved_hugetlb.sh @@ -100,7 +100,7 @@ function setup_cgroup() { echo writing cgroup limit: "$cgroup_limit" echo "$cgroup_limit" >$cgroup_path/$name/hugetlb.${MB}MB.$fault_limit_fi= le =20 - echo writing reseravation limit: "$reservation_limit" + echo writing reservation limit: "$reservation_limit" echo "$reservation_limit" > \ $cgroup_path/$name/hugetlb.${MB}MB.$reservation_limit_file =20 @@ -112,41 +112,46 @@ function setup_cgroup() { fi } =20 +function wait_for_file_value() { + local path=3D"$1" + local expect=3D"$2" + local max_tries=3D"120" + + local i cur + for ((i=3D1; i<=3Dmax_tries; i++)); do + cur=3D"$(cat "$path")" + if [[ "$cur" =3D=3D "$expect" ]]; then + return 0 + fi + echo "Waiting for $path to become '$expect' (current: '$cur') (try $i/= $max_tries)" + sleep 0.5 + done + + echo "ERROR: timeout waiting for $path to become '$expect' (last: '$cur'= )" + return 1 +} + function wait_for_hugetlb_memory_to_get_depleted() { local cgroup=3D"$1" local path=3D"$cgroup_path/$cgroup/hugetlb.${MB}MB.$reservation_usage_fi= le" - # Wait for hugetlbfs memory to get depleted. - while [ $(cat $path) !=3D 0 ]; do - echo Waiting for hugetlb memory to get depleted. - cat $path - sleep 0.5 - done + + wait_for_file_value "$path" "0" } =20 function wait_for_hugetlb_memory_to_get_reserved() { local cgroup=3D"$1" local size=3D"$2" - local path=3D"$cgroup_path/$cgroup/hugetlb.${MB}MB.$reservation_usage_fi= le" - # Wait for hugetlbfs memory to get written. - while [ $(cat $path) !=3D $size ]; do - echo Waiting for hugetlb memory reservation to reach size $size. - cat $path - sleep 0.5 - done + + wait_for_file_value "$path" "$size" } =20 function wait_for_hugetlb_memory_to_get_written() { local cgroup=3D"$1" local size=3D"$2" - local path=3D"$cgroup_path/$cgroup/hugetlb.${MB}MB.$fault_usage_file" - # Wait for hugetlbfs memory to get written. - while [ $(cat $path) !=3D $size ]; 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Sun, 21 Dec 2025 08:58:31 +0000 (UTC) Received: from dell-per7425-02.rhts.eng.pek2.redhat.com (dell-per7425-02.rhts.eng.pek2.redhat.com [10.73.116.18]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9937030001A2; Sun, 21 Dec 2025 08:58:27 +0000 (UTC) From: Li Wang To: akpm@linux-foundation.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: David Hildenbrand , Mark Brown , Shuah Khan , Waiman Long Subject: [PATCH v2 3/3] selftests/mm/charge_reserved_hugetlb: fix hugetlbfs mount size for large hugepages Date: Sun, 21 Dec 2025 16:58:10 +0800 Message-ID: <20251221085810.3163919-4-liwang@redhat.com> In-Reply-To: <20251221085810.3163919-1-liwang@redhat.com> References: <20251221085810.3163919-1-liwang@redhat.com> 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 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Content-Type: text/plain; charset="utf-8" charge_reserved_hugetlb.sh mounts a hugetlbfs instance at /mnt/huge with a fixed size of 256M. On systems with large base hugepages (e.g. 512MB), this is smaller than a single hugepage, so the hugetlbfs mount ends up with effectively zero capacity (often visible as size=3D0 in mount output). As a result, write_to_hugetlbfs fails with ENOMEM and the test can hang waiting for progress. --- Error log --- # uname -r 6.12.0-xxx.el10.aarch64+64k #./charge_reserved_hugetlb.sh -cgroup-v2 # ----------------------------------------- ... # nr hugepages =3D 10 # writing cgroup limit: 5368709120 # writing reseravation limit: 5368709120 ... # write_to_hugetlbfs: Error mapping the file: Cannot allocate memory # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 # Waiting for hugetlb memory reservation to reach size 2684354560. # 0 ... # mount |grep /mnt/huge none on /mnt/huge type hugetlbfs (rw,relatime,seclabel,pagesize=3D512M,si= ze=3D0) # grep -i huge /proc/meminfo ... HugePages_Total: 10 HugePages_Free: 10 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 524288 kB Hugetlb: 5242880 kB Mount hugetlbfs with size=3D${size}, the number of bytes the test will reserve/write, so the filesystem capacity is sufficient regardless of HugeTLB page size. Signed-off-by: Li Wang Cc: David Hildenbrand Cc: Mark Brown Cc: Shuah Khan Cc: Waiman Long --- tools/testing/selftests/mm/charge_reserved_hugetlb.sh | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/mm/charge_reserved_hugetlb.sh b/tools/= testing/selftests/mm/charge_reserved_hugetlb.sh index 249a5776c074..ac2744dbc0bd 100755 --- a/tools/testing/selftests/mm/charge_reserved_hugetlb.sh +++ b/tools/testing/selftests/mm/charge_reserved_hugetlb.sh @@ -295,7 +295,7 @@ function run_test() { setup_cgroup "hugetlb_cgroup_test" "$cgroup_limit" "$reservation_limit" =20 mkdir -p /mnt/huge - mount -t hugetlbfs -o pagesize=3D${MB}M,size=3D256M none /mnt/huge + mount -t hugetlbfs -o pagesize=3D${MB}M,size=3D${size} none /mnt/huge =20 write_hugetlbfs_and_get_usage "hugetlb_cgroup_test" "$size" "$populate" \ "$write" "/mnt/huge/test" "$method" "$private" "$expect_failure" \ @@ -349,7 +349,7 @@ function run_multiple_cgroup_test() { setup_cgroup "hugetlb_cgroup_test2" "$cgroup_limit2" "$reservation_limit= 2" =20 mkdir -p /mnt/huge - mount -t hugetlbfs -o pagesize=3D${MB}M,size=3D256M none /mnt/huge + mount -t hugetlbfs -o pagesize=3D${MB}M,size=3D${size} none /mnt/huge =20 write_hugetlbfs_and_get_usage "hugetlb_cgroup_test1" "$size1" \ "$populate1" "$write1" "/mnt/huge/test1" "$method" "$private" \ --=20 2.49.0