From: Daniel Borkmann <daniel@iogearbox.net>
To: Dmitry Vyukov <dvyukov@google.com>,
syzkaller <syzkaller@googlegroups.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
David Miller <davem@davemloft.net>,
Alexei Starovoitov <ast@kernel.org>,
netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Kostya Serebryany <kcc@google.com>,
Alexander Potapenko <glider@google.com>,
Eric Dumazet <edumazet@google.com>,
Sasha Levin <sasha.levin@oracle.com>
Subject: Re: [PATCH net] bpf: fix allocation warnings in bpf maps and integer overflow
Date: Mon, 30 Nov 2015 15:13:47 +0100 [thread overview]
Message-ID: <565C599B.1020902@iogearbox.net> (raw)
In-Reply-To: <CACT4Y+aGR2p6VCLgqg5otFU+0unPGp4rYe9jyCGLL1hg8D5_vA@mail.gmail.com>
On 11/30/2015 02:57 PM, Dmitry Vyukov wrote:
...
> kamlloc produces a WARNING if you try to allocate more than it ever
> possibly can (KMALLOC_SHIFT_MAX).
Sure, I understand that.
The kzalloc() in array_map_alloc() is however with __GFP_NOWARN flag already.
The warning only triggers in mm if:
WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
Your test case is using ca.map_type = 1, which is BPF_MAP_TYPE_HASH. So on
update you're triggering the kmalloc() in htab_map_update_elem().
I'm just asking about the added change in array map.
Thanks,
Daniel
next prev parent reply other threads:[~2015-11-30 14:13 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-29 13:18 user-controllable kmalloc size in bpf syscall Dmitry Vyukov
2015-11-29 18:21 ` Alexei Starovoitov
2015-11-30 0:59 ` [PATCH net] bpf: fix allocation warnings in bpf maps and integer overflow Alexei Starovoitov
2015-11-30 13:52 ` Daniel Borkmann
2015-11-30 13:57 ` Dmitry Vyukov
2015-11-30 14:13 ` Daniel Borkmann [this message]
2015-11-30 14:16 ` Dmitry Vyukov
2015-11-30 14:34 ` Daniel Borkmann
2015-11-30 18:13 ` Alexei Starovoitov
2015-11-30 22:16 ` Daniel Borkmann
2015-11-30 23:30 ` Alexei Starovoitov
2015-12-03 4:36 ` David Miller
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