From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: EBPF-triggered WARNING at mm/percpu.c:1361 in v4-14-rc2 Date: Thu, 28 Sep 2017 07:52:11 -0700 Message-ID: <20170928145211.GD15129@devbig577.frc2.facebook.com> References: <20170928112727.GA11310@leverpostej> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, syzkaller@googlegroups.com, Daniel Borkmann , "David S. Miller" , Alexei Starovoitov , Christoph Lameter To: Mark Rutland Return-path: Content-Disposition: inline In-Reply-To: <20170928112727.GA11310@leverpostej> Sender: owner-linux-mm@kvack.org List-Id: netdev.vger.kernel.org Hello, On Thu, Sep 28, 2017 at 12:27:28PM +0100, Mark Rutland wrote: > diff --git a/mm/percpu.c b/mm/percpu.c > index 59d44d6..f731c45 100644 > --- a/mm/percpu.c > +++ b/mm/percpu.c > @@ -1355,8 +1355,13 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved, > bits = size >> PCPU_MIN_ALLOC_SHIFT; > bit_align = align >> PCPU_MIN_ALLOC_SHIFT; > > - if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE || > - !is_power_of_2(align))) { > + if (unlikely(size > PCPU_MIN_UNIT_SIZE)) { > + pr_warn("cannot allocate pcpu chunk of size %zu (max %zu)\n", > + size, PCPU_MIN_UNIT_SIZE); WARN_ONCE() probably is the better choice here. We wanna know who tries to allocate larger than the supported size and increase the size limit if warranted. Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org