From: Alexei Starovoitov <ast@fb.com>
To: Eric Dumazet <eric.dumazet@gmail.com>,
Alexei Starovoitov <ast@kernel.org>, <davem@davemloft.net>
Cc: <daniel@iogearbox.net>, <edumazet@google.com>,
<netdev@vger.kernel.org>, <kernel-team@fb.com>
Subject: Re: [PATCH bpf] bpf: fix 32-bit divide by zero
Date: Thu, 18 Jan 2018 14:40:59 -0800 [thread overview]
Message-ID: <e79a20ce-0d11-3d37-ff81-e46f1849903e@fb.com> (raw)
In-Reply-To: <1516314654.3606.28.camel@gmail.com>
On 1/18/18 2:30 PM, Eric Dumazet wrote:
> On Fri, 2018-01-12 at 18:59 -0800, Alexei Starovoitov wrote:
>> due to some JITs doing if (src_reg == 0) check in 64-bit mode
>> for div/mod opreations mask upper 32-bits of src register
>> before doing the check
>>
>
> Is the plan to fix JIT, and if they can all be fixed,
> revert this patch ?
No need to fix JITs.
I'd rather remove 'cmp rX, 0' from JITs and let verifier emit it.
It's more generic and gives us flexibility to decide what to do
with divide by zero and other exceptions.
next prev parent reply other threads:[~2018-01-18 22:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-13 2:59 [PATCH bpf] bpf: fix 32-bit divide by zero Alexei Starovoitov
2018-01-13 16:45 ` Alexei Starovoitov
2018-01-14 22:06 ` Daniel Borkmann
2018-01-18 22:30 ` Eric Dumazet
2018-01-18 22:40 ` Alexei Starovoitov [this message]
2018-01-18 23:33 ` Daniel Borkmann
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