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From: "Jin, Yao" <yao.jin@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@redhat.com, oleg@redhat.com, acme@kernel.org,
	jolsa@kernel.org, Linux-kernel@vger.kernel.org,
	ak@linux.intel.com, kan.liang@intel.com, yao.jin@intel.com,
	alexander.shishkin@linux.intel.com, mark.rutland@arm.com
Subject: Re: [PATCH v1 2/2] perf/core: Fake regs for leaked kernel samples
Date: Tue, 11 Aug 2020 16:31:10 +0800	[thread overview]
Message-ID: <dbc68bbf-b1a8-77ab-c89c-2d890a0382cc@linux.intel.com> (raw)
In-Reply-To: <20200811075924.GU3982@worktop.programming.kicks-ass.net>

Hi Peter,

On 8/11/2020 3:59 PM, Peter Zijlstra wrote:
> On Tue, Aug 11, 2020 at 03:50:43PM +0800, Jin, Yao wrote:
>> Could I post v2 which basically refers to your patch but removes some
>> conditions since I see some issues in test if we use these conditions.
>>
>>   1. Remove '!event->attr.exclude_hv || !event->attr.exclude_host ||
>>      !event->attr.exclude_guest' at the entry of sanitize_sample_regs().
>>
>>   2. Remove '!attr.exclude_hv || !attr.exclude_host || !attr.exclude_guest'
>>      at the perf_event_open syscall entry.
> 
> exclude_host, maybe -- due to the dodgy semantics of it, but the others
> should definitely be there.
> 

exclude_guest and exclude_hv are tricky too.

If we do 'perf record -e cycles:u' in both host and guest, we can see:

event->attr.exclude_guest = 0

thus sanitize_sample_regs() returns regs directly even if exclude_kernel = 1.

And in guest, exclude_hv = 0, it's out of my expectation too.

Thanks
Jin Yao

  reply	other threads:[~2020-08-11  8:31 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-31  2:56 [PATCH v1 1/2] Missing instruction_pointer_set() instances Jin Yao
2020-07-31  2:56 ` [PATCH v1 2/2] perf/core: Fake regs for leaked kernel samples Jin Yao
2020-08-04 11:49   ` peterz
2020-08-05  2:15     ` Jin, Yao
2020-08-05 12:44       ` peterz
2020-08-05 12:57         ` peterz
2020-08-06  2:26         ` Jin, Yao
2020-08-06  9:18           ` peterz
2020-08-06  9:24             ` peterz
2020-08-07  5:32               ` Jin, Yao
2020-08-06 11:00             ` peterz
2020-08-07  6:24               ` Jin, Yao
2020-08-07  9:02                 ` peterz
2020-08-10  2:03                   ` Jin, Yao
2020-08-07  5:23             ` Jin, Yao
2020-08-11  7:50           ` Jin, Yao
2020-08-11  7:59             ` Peter Zijlstra
2020-08-11  8:31               ` Jin, Yao [this message]
2020-08-11  8:45                 ` Peter Zijlstra
2020-08-12  3:52                   ` Jin, Yao
2020-08-12  7:25                     ` Like Xu
2020-08-04 11:31 ` [PATCH v1 1/2] Missing instruction_pointer_set() instances peterz
2020-08-05  0:26   ` Jin, Yao
2020-08-04 21:31 ` Max Filippov

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