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From: Muchun Song In-Reply-To: Date: Tue, 28 Mar 2023 21:03:15 +0800 Cc: Muchun Song , glider@google.com, dvyukov@google.com, akpm@linux-foundation.org, jannh@google.com, sjpark@amazon.de, kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <20230328095807.7014-1-songmuchun@bytedance.com> <20230328095807.7014-3-songmuchun@bytedance.com> To: Marco Elver X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 31875C0014 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: zc6ikaxbhq3bke8b489q49x13hx1k8rh X-HE-Tag: 1680008631-534027 X-HE-Meta: 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 XRDBVCNB UxVeh3nta21MJwp89t03WD+vzP51WSSI8AD23V9oDNSidAz+8a94jsF29eSqCcdHe57FOPh3NRk17QSQ8DUq5KjBzZR2owMnw0vD2FB+1YhHJ6KnD8leTitzZVzhC03tBJJTLavtOssCiH5vdaXTMkhe5O5EHF39rwYaQLkaohm/X6s1b6n03XGLy3zc+/2dMEaEi6TGDNbBgOjxZi1yf2xRp78AhYnI1kWda5LNTjVhoEeqkcbaJNOHj0Q== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > On Mar 28, 2023, at 18:14, Marco Elver wrote: >=20 > On Tue, 28 Mar 2023 at 11:58, 'Muchun Song' via kasan-dev > wrote: >>=20 >> Check kfence pool size at building time to expose problem ASAP. >>=20 >> Signed-off-by: Muchun Song >> --- >> mm/kfence/core.c | 7 +++---- >> 1 file changed, 3 insertions(+), 4 deletions(-) >>=20 >> diff --git a/mm/kfence/core.c b/mm/kfence/core.c >> index de62a84d4830..6781af1dfa66 100644 >> --- a/mm/kfence/core.c >> +++ b/mm/kfence/core.c >> @@ -841,10 +841,9 @@ static int kfence_init_late(void) >> return -ENOMEM; >> __kfence_pool =3D page_to_virt(pages); >> #else >> - if (nr_pages > MAX_ORDER_NR_PAGES) { >> - pr_warn("KFENCE_NUM_OBJECTS too large for buddy = allocator\n"); >> - return -EINVAL; >> - } >> + BUILD_BUG_ON_MSG(get_order(KFENCE_POOL_SIZE) > MAX_ORDER, >> + "CONFIG_KFENCE_NUM_OBJECTS is too large for = buddy allocator"); >> + >=20 > It's perfectly valid to want to use KFENCE with a very large pool that > is initialized on boot, and simply sacrifice the ability to initialize > late. You are right. I didn=E2=80=99t realize this. Thanks=20 >=20 > Nack.