From: Frederic Weisbecker <fweisbec@gmail.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>,
linux-kernel@vger.kernel.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
trinity@vger.kernel.org, Jiri Olsa <jolsa@redhat.com>
Subject: Re: [PATCH 2/2] hw_breakpoint: Use cpu_possible_mask in {reserve,release}_bp_slot()
Date: Sat, 15 Jun 2013 14:46:41 +0200 [thread overview]
Message-ID: <20130615124639.GA1965@somewhere.redhat.com> (raw)
In-Reply-To: <20130601182139.GC4861@redhat.com>
On Sat, Jun 01, 2013 at 08:21:39PM +0200, Oleg Nesterov wrote:
> fetch_bp_busy_slots() and toggle_bp_slot() use for_each_online_cpu(),
> this is obviously wrong wrt cpu_up() or cpu_down(), we can over/under
> account the per-cpu numbers.
>
> For example:
>
> # echo 0 >> /sys/devices/system/cpu/cpu1/online
> # perf record -e mem:0x10 -p 1 &
> # echo 1 >> /sys/devices/system/cpu/cpu1/online
> # perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10 -C1 -a &
> # taskset -p 0x2 1
>
> triggers the same WARN_ONCE("Can't find any breakpoint slot") in
> arch_install_hw_breakpoint().
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
> Cc: <stable@vger.kernel.org>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
next prev parent reply other threads:[~2013-06-15 12:46 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-20 16:19 WARN_ONCE in arch/x86/kernel/hw_breakpoint.c Vince Weaver
2013-05-28 17:00 ` Oleg Nesterov
2013-05-28 17:28 ` Oleg Nesterov
2013-05-28 18:47 ` Oleg Nesterov
2013-05-29 16:32 ` [MAYBEPATCH] : " Oleg Nesterov
2013-06-01 18:20 ` [PATCH 0/2]: " Oleg Nesterov
2013-06-01 18:21 ` [PATCH 1/2] hw_breakpoint: Fix cpu check in task_bp_pinned(cpu) Oleg Nesterov
2013-06-13 14:20 ` Frederic Weisbecker
2013-06-01 18:21 ` [PATCH 2/2] hw_breakpoint: Use cpu_possible_mask in {reserve,release}_bp_slot() Oleg Nesterov
2013-06-15 12:46 ` Frederic Weisbecker [this message]
2013-06-01 19:45 ` [PATCH 0/3] hw_breakpoint: cleanups Oleg Nesterov
2013-06-01 19:45 ` [PATCH 1/3] hw_breakpoint: Simplify list/idx mess in toggle_bp_slot() paths Oleg Nesterov
2013-06-15 12:59 ` Frederic Weisbecker
2013-06-01 19:46 ` [PATCH 2/3] hw_breakpoint: Simplify the "weight" usage " Oleg Nesterov
2013-06-15 13:14 ` Frederic Weisbecker
2013-06-01 19:46 ` [PATCH 3/3] hw_breakpoint: Introduce cpumask_of_bp() Oleg Nesterov
2013-06-15 13:29 ` Frederic Weisbecker
2013-06-13 14:01 ` [PATCH 0/3] hw_breakpoint: cleanups Frederic Weisbecker
2013-06-13 15:15 ` Oleg Nesterov
2013-06-13 15:24 ` Frederic Weisbecker
2013-06-02 19:49 ` [PATCH 0/2] hw_breakpoint: more cleanups Oleg Nesterov
2013-06-02 19:50 ` [PATCH 1/2] hw_breakpoint: Simplify *register_wide_hw_breakpoint() Oleg Nesterov
2013-06-18 0:12 ` Frederic Weisbecker
2013-06-02 19:50 ` [PATCH 2/2] hw_breakpoint: Introduce "struct bp_cpuinfo" Oleg Nesterov
2013-06-18 12:37 ` Frederic Weisbecker
2013-06-18 14:42 ` Oleg Nesterov
2013-06-18 17:01 ` Frederic Weisbecker
2013-06-19 15:54 ` Oleg Nesterov
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