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From: Martin KaFai Lau <kafai@fb.com>
To: John Fastabend <john.fastabend@gmail.com>
Cc: <daniel@iogearbox.net>, <ast@kernel.org>,
	<netdev@vger.kernel.org>, <bpf@vger.kernel.org>
Subject: Re: [bpf PATCH v2 0/5] Fix sock_ops field read splat
Date: Wed, 29 Jul 2020 14:57:32 -0700	[thread overview]
Message-ID: <20200729215717.mkgd4hnokybwzsda@kafai-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <159603940602.4454.2991262810036844039.stgit@john-Precision-5820-Tower>

On Wed, Jul 29, 2020 at 09:22:36AM -0700, John Fastabend wrote:
> Doing some refactoring resulted in a kernel splat when reading sock_ops
> fields.
> 
> Patch 1, has the details and proposed fix for sock_ops sk field access.
> 
> Patch 2, has the details and proposed fix for reading sock_ops->sk field
> 
> Patch 3, Gives a reproducer and test to verify the fix. I used the netcnt
> program to test this because I wanted a splat to be generated which can
> only be done if we have real traffic exercising the code.
> 
> Patch 4, Is an optional patch. While doing above I wanted to also verify
> loads were OK. The code looked good, but I wanted some xlated code to
> review as well. It seems like a good idea to add it here or at least
> shouldn't hurt. I could push it into bpf-next if folks want.
> 
> Patch 5, Add reproducers for reading scok_ops->sk field.
> 
> I split Patch1 and Patch2 into two two patches because they have different
> fixes tags. Seems like this will help with backporting. They could be
> squashed though if folks want.
> 
> For selftests I was fairly verbose creating three patches each with the
> associated xlated code to handle each of the three cases. My hope is this
> helps the reader understand issues and review fixes. Its more or less
> how I debugged the issue and created reproducers so it at least helped
> me to have them logically different patches.
LGTM also.  Thanks for the fixes and the tests!

Acked-by: Martin KaFai Lau <kafai@fb.com>

      parent reply	other threads:[~2020-07-29 21:58 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-29 16:22 [bpf PATCH v2 0/5] Fix sock_ops field read splat John Fastabend
2020-07-29 16:22 ` [bpf PATCH v2 1/5] bpf: sock_ops ctx access may stomp registers in corner case John Fastabend
2020-07-29 21:29   ` Song Liu
2020-07-31 12:25   ` Daniel Borkmann
2020-07-31 22:46     ` John Fastabend
2020-07-29 16:23 ` [bpf PATCH v2 2/5] bpf: sock_ops sk access may stomp registers when dst_reg = src_reg John Fastabend
2020-07-29 21:30   ` Song Liu
2020-07-29 16:23 ` [bpf PATCH v2 3/5] bpf, selftests: Add tests for ctx access in sock_ops with single register John Fastabend
2020-07-29 21:35   ` Song Liu
2020-07-29 16:23 ` [bpf PATCH v2 4/5] bpf, selftests: Add tests for sock_ops load with r9, r8.r7 registers John Fastabend
2020-07-29 21:36   ` Song Liu
2020-07-29 16:24 ` [bpf PATCH v2 5/5] bpf, selftests: Add tests to sock_ops for loading sk John Fastabend
2020-07-29 21:36   ` Song Liu
2020-07-29 21:57 ` Martin KaFai Lau [this message]

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