From: Peter Zijlstra <peterz@infradead.org>
To: Alexei Starovoitov <ast@kernel.org>
Cc: davem@davemloft.net, daniel@iogearbox.net, edumazet@google.com,
jannh@google.com, netdev@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH bpf-next 1/4] bpf: fix lockdep false positive in percpu_freelist
Date: Wed, 30 Jan 2019 11:21:26 +0100 [thread overview]
Message-ID: <20190130102126.GF2278@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190130040458.2544340-2-ast@kernel.org>
On Tue, Jan 29, 2019 at 08:04:55PM -0800, Alexei Starovoitov wrote:
>
> It has been explained that is a false positive here:
> https://lkml.org/lkml/2018/7/25/756
Please, no external references like that. The best option is to fully
include the explanation here so that a future software archeology
student (note, this might be yourself in a years time) can find all
relevant information in the git history.
Or, if you _really_ _really_ have to refer to external sources, use:
https://lkml.kernel.org/r/${msg_id}
which is a controlled URL and can be made to point to any archive
(currently, and sadly, lore.kernel.org).
Also, since it includes the whole msg_id, people can trivially find the
email in their local archive.
While I agree that lkml.org is a _MUCH_ saner interface than lore (which
causes eye and brain cancer for just looking at it), it is a _really_
flaky website and the url contains no clues for finding it in the local
archive.
> Recap:
> - stackmap uses pcpu_freelist
> - The lock in pcpu_freelist is a percpu lock
> - stackmap is only used by tracing bpf_prog
> - A tracing bpf_prog cannot be run if another bpf_prog
> has already been running (ensured by the percpu bpf_prog_active counter).
next prev parent reply other threads:[~2019-01-30 10:21 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-30 4:04 [PATCH bpf-next 0/4] bpf: fixes for lockdep and deadlock Alexei Starovoitov
2019-01-30 4:04 ` [PATCH bpf-next 1/4] bpf: fix lockdep false positive in percpu_freelist Alexei Starovoitov
2019-01-30 10:21 ` Peter Zijlstra [this message]
2019-01-30 19:27 ` Alexei Starovoitov
2019-01-30 19:53 ` Peter Zijlstra
2019-01-30 20:18 ` Alexei Starovoitov
2019-01-30 4:04 ` [PATCH bpf-next 2/4] bpf: fix lockdep false positive in stackmap Alexei Starovoitov
2019-01-30 10:15 ` Peter Zijlstra
2019-01-30 19:30 ` Alexei Starovoitov
2019-01-30 19:42 ` Waiman Long
2019-01-30 20:10 ` Alexei Starovoitov
2019-01-30 21:11 ` Waiman Long
2019-01-30 21:32 ` Waiman Long
2019-01-31 2:01 ` Alexei Starovoitov
2019-01-31 2:48 ` Waiman Long
2019-02-06 3:21 ` Eric Dumazet
2019-02-06 3:30 ` Alexei Starovoitov
2019-02-06 3:40 ` Eric Dumazet
2019-01-30 19:44 ` Peter Zijlstra
2019-01-30 20:05 ` Waiman Long
2019-01-30 4:04 ` [PATCH bpf-next 3/4] bpf: fix lockdep false positive in bpf_prog_register Alexei Starovoitov
2019-01-30 10:10 ` Peter Zijlstra
2019-01-30 10:37 ` Peter Zijlstra
2019-01-30 19:32 ` Alexei Starovoitov
2019-01-30 19:46 ` Peter Zijlstra
2019-01-30 4:04 ` [PATCH bpf-next 4/4] bpf: Fix syscall's stackmap lookup potential deadlock Alexei Starovoitov
2019-01-30 4:07 ` [PATCH bpf-next 0/4] bpf: fixes for lockdep and deadlock Alexei Starovoitov
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