From: peterz@infradead.org
To: "Jin, Yao" <yao.jin@linux.intel.com>
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: Wed, 5 Aug 2020 14:57:07 +0200 [thread overview]
Message-ID: <20200805125707.GC35926@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200805124454.GP2657@hirez.programming.kicks-ass.net>
On Wed, Aug 05, 2020 at 02:44:54PM +0200, peterz@infradead.org wrote:
> How's this?
Clearly I didn't even hold it near a compiler...
> ---
> kernel/events/core.c | 38 +++++++++++++++++++++++++++++++++-----
> 1 file changed, 33 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 7c436d705fbd..3e4e328b521a 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -6988,23 +6988,49 @@ perf_callchain(struct perf_event *event, struct pt_regs *regs)
> return callchain ?: &__empty_callchain;
> }
>
> +/*
> + * Due to interrupt latency (skid), we may enter the kernel before taking the
> + * PMI, even if the PMU is configured to only count user events. To avoid
> + * leaking kernel addresses, use task_pt_regs(), when available.
> + */
> +static struct pt_regs *sanitize_sample_regs(struct perf_event *event, struct pt_regs *regs)
> +{
> + struct pt_regs *sample_regs = regs;
> +
> + /* user only */
> + if (!event->attr.exclude_kernel || !event->attr.exclude_hv ||
> + !event->attr.exclude_host || !event->attr.exclude_guest)
> + return sample_regs;
> +
> + if (sample_regs(regs))
> + return sample_regs;
That wants to he:
if (user_regs(regs))
return sample_regs;
> +
> + if (!(current->flags & PF_KTHREAD)) {
s/{//
> + sample_regs = task_pt_regs(current);
> + else
> + instruction_pointer_set(regs, -1L);
> +
> + return sample_regs;
> +}
next prev parent reply other threads:[~2020-08-05 16:50 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 [this message]
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
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200805125707.GC35926@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=Linux-kernel@vger.kernel.org \
--cc=acme@kernel.org \
--cc=ak@linux.intel.com \
--cc=alexander.shishkin@linux.intel.com \
--cc=jolsa@kernel.org \
--cc=kan.liang@intel.com \
--cc=mark.rutland@arm.com \
--cc=mingo@redhat.com \
--cc=oleg@redhat.com \
--cc=yao.jin@intel.com \
--cc=yao.jin@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).