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From: David Laight <David.Laight@ACULAB.COM>
To: "'Daniel Borkmann'" <daniel@iogearbox.net>,
	"davem@davemloft.net" <davem@davemloft.net>
Cc: "tj@kernel.org" <tj@kernel.org>,
	"ast@kernel.org" <ast@kernel.org>,
	"john.fastabend@gmail.com" <john.fastabend@gmail.com>,
	"mark.rutland@arm.com" <mark.rutland@arm.com>,
	"richard@nod.at" <richard@nod.at>,
	"sp3485@columbia.edu" <sp3485@columbia.edu>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH net 0/3] Fix for BPF devmap percpu allocation splat
Date: Tue, 17 Oct 2017 15:03:07 +0000	[thread overview]
Message-ID: <063D6719AE5E284EB5DD2968C1650D6DD009980D@AcuExch.aculab.com> (raw)
In-Reply-To: <cover.1508251210.git.daniel@iogearbox.net>

From: Daniel Borkmann
> Sent: 17 October 2017 15:56
> 
> The set fixes a splat in devmap percpu allocation when we alloc
> the flush bitmap. Patch 1 is a prerequisite for the fix in patch 2,
> patch 1 is rather small, so if this could be routed via -net, for
> example, with Tejun's Ack that would be good. Patch 3 gets rid of
> remaining PCPU_MIN_UNIT_SIZE checks, which are percpu allocator
> internals and should not be used.

Does it make sense to allow the user program to try to allocate ever
smaller very large maps until it finds one that succeeds - thus
using up all the percpu space?

Or is this a 'root only' 'shoot self in foot' job?

	David

  parent reply	other threads:[~2017-10-17 15:03 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-17 14:55 [PATCH net 0/3] Fix for BPF devmap percpu allocation splat Daniel Borkmann
2017-10-17 14:55 ` [PATCH net 1/3] mm, percpu: add support for __GFP_NOWARN flag Daniel Borkmann
2017-10-17 15:53   ` Alexei Starovoitov
2017-10-17 14:55 ` [PATCH net 2/3] bpf: fix splat for illegal devmap percpu allocation Daniel Borkmann
2017-10-17 15:54   ` Alexei Starovoitov
2017-10-17 16:28   ` John Fastabend
2017-10-17 14:55 ` [PATCH net 3/3] bpf: do not test for PCPU_MIN_UNIT_SIZE before percpu allocations Daniel Borkmann
2017-10-17 15:55   ` Alexei Starovoitov
2017-10-17 16:29   ` John Fastabend
2017-10-17 15:03 ` David Laight [this message]
2017-10-17 15:11   ` [PATCH net 0/3] Fix for BPF devmap percpu allocation splat Daniel Borkmann
2017-10-18 13:25 ` Tejun Heo
2017-10-18 14:03   ` Daniel Borkmann
2017-10-18 14:22     ` Daniel Borkmann
2017-10-18 15:28       ` Alexei Starovoitov
2017-10-18 15:31         ` Daniel Borkmann
2017-10-18 21:45   ` Dennis Zhou
2017-10-21 16:00     ` Tejun Heo
2017-10-19 12:14 ` David Miller

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