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Groups > linux.kernel > #1602660
| From | Eric Dumazet <eric.dumazet@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t |
| Date | 2017-03-16 18:00 +0100 |
| Message-ID | <tlGUN-197-7@gated-at.bofh.it> (permalink) |
| References | <tlFvH-gv-7@gated-at.bofh.it> <tlFFo-lI-31@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, 2017-03-16 at 17:28 +0200, Elena Reshetova wrote:
> refcount_t type and corresponding API should be
> used instead of atomic_t when the variable is used as
> a reference counter. This allows to avoid accidental
> refcounter overflows that might lead to use-after-free
> situations.
...
> static __always_inline void sock_hold(struct sock *sk)
> {
> - atomic_inc(&sk->sk_refcnt);
> + refcount_inc(&sk->sk_refcnt);
> }
>
While I certainly see the value of these refcount_t, we have a very
different behavior on these atomic_inc() which were doing a single
inlined LOCK RMW on x86.
We now call an external function performing a
atomic_read(), various ops/tests, then atomic_cmpxchg_relaxed(), in a
loop, loosing the nice ability for x86 of preventing live locks.
Looks a lot of bloat, just to be able to chase hypothetical bugs in the
kernel.
I would love to have a way to enable extra debugging when I want a debug
kernel, like LOCKDEP or KASAN.
By adding all this bloat, we assert linux kernel is terminally buggy and
every atomic_inc() we did was suspicious, and need to be always
instrumented/validated.
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[PATCH 00/17] net subsystem refcount conversions Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:30 +0100
[PATCH 02/17] net: convert neigh_params.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:30 +0100
[PATCH 10/17] net: convert in_device.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
[PATCH 12/17] net: convert unix_address.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
[PATCH 14/17] net: convert inet_frag_queue.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
[PATCH 01/17] net: convert neighbour.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
[PATCH 11/17] net: convert netpoll_info.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
[PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Eric Dumazet <eric.dumazet@gmail.com> - 2017-03-16 18:00 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Kees Cook <keescook@chromium.org> - 2017-03-16 18:40 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t David Miller <davem@davemloft.net> - 2017-03-16 20:20 +0100
RE: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-03-17 08:50 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Eric Dumazet <eric.dumazet@gmail.com> - 2017-03-17 17:20 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Herbert Xu <herbert@gondor.apana.org.au> - 2017-03-18 18:00 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t David Miller <davem@davemloft.net> - 2017-03-19 02:40 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Peter Zijlstra <peterz@infradead.org> - 2017-03-20 11:50 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Peter Zijlstra <peterz@infradead.org> - 2017-03-20 14:30 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Peter Zijlstra <peterz@infradead.org> - 2017-03-20 14:50 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Eric Dumazet <eric.dumazet@gmail.com> - 2017-03-20 16:00 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Eric Dumazet <eric.dumazet@gmail.com> - 2017-03-20 17:20 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Eric Dumazet <eric.dumazet@gmail.com> - 2017-03-20 17:40 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Eric Dumazet <eric.dumazet@gmail.com> - 2017-03-20 16:30 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Peter Zijlstra <peterz@infradead.org> - 2017-03-20 16:50 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Kees Cook <keescook@chromium.org> - 2017-03-21 21:50 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Eric Dumazet <eric.dumazet@gmail.com> - 2017-03-21 22:30 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t David Miller <davem@davemloft.net> - 2017-03-21 23:40 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Kees Cook <keescook@chromium.org> - 2017-03-22 01:00 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Eric Dumazet <eric.dumazet@gmail.com> - 2017-03-22 03:10 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Peter Zijlstra <peterz@infradead.org> - 2017-03-22 13:30 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Eric Dumazet <eric.dumazet@gmail.com> - 2017-03-22 14:30 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Peter Zijlstra <peterz@infradead.org> - 2017-03-22 15:40 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Eric Dumazet <eric.dumazet@gmail.com> - 2017-03-22 16:00 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Peter Zijlstra <peterz@infradead.org> - 2017-03-22 16:10 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Eric Dumazet <eric.dumazet@gmail.com> - 2017-03-22 16:30 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Peter Zijlstra <peterz@infradead.org> - 2017-03-22 18:00 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Kees Cook <keescook@chromium.org> - 2017-03-22 20:10 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Peter Zijlstra <peterz@infradead.org> - 2017-03-22 14:50 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Herbert Xu <herbert@gondor.apana.org.au> - 2017-03-20 15:50 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Herbert Xu <herbert@gondor.apana.org.au> - 2017-03-20 14:50 +0100
RE: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t David Laight <David.Laight@ACULAB.COM> - 2017-03-20 15:20 +0100
Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t Peter Zijlstra <peterz@infradead.org> - 2017-03-20 15:30 +0100
RE: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t David Laight <David.Laight@ACULAB.COM> - 2017-03-20 16:10 +0100
[PATCH 05/17] net: convert sk_buff_fclones.fclone_ref from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
[PATCH 15/17] net: convert net.passive from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
[PATCH 16/17] net: convert netlbl_lsm_cache.refcount from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
[PATCH 09/17] net: convert ip_mc_list.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
[PATCH 04/17] net: convert sk_buff.users from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
[PATCH 08/17] net: convert sk_filter.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
Re: [PATCH 08/17] net: convert sk_filter.refcnt from atomic_t to refcount_t Daniel Borkmann <daniel@iogearbox.net> - 2017-03-16 17:10 +0100
RE: [PATCH 08/17] net: convert sk_filter.refcnt from atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-03-17 09:20 +0100
[PATCH 17/17] net: convert packet_fanout.sk_ref from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
[PATCH 06/17] net: convert sock.sk_wmem_alloc from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
[PATCH 13/17] net: convert fib_rule.refcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-03-16 16:40 +0100
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