From: sashiko-bot@kernel.org
To: "Jaidev Shastri" <jaidevshastri@vt.edu>
Cc: linux-perf-users@vger.kernel.org
Subject: Re: [PATCH 2/3] perf/core: install the guest callbacks before the guest_state gate
Date: Tue, 22 Sep 2026 01:25:20 +0000 [thread overview]
Message-ID: <20260922012520.B21521F000FF@smtp.kernel.org> (raw)
In-Reply-To: <20260921-mb-perf-core-v1-2-ac56a719c02b@vt.edu>
> From: Jaidev Shastri <jaidevshastri@vt.edu>
>
> perf_register_guest_info_callbacks() updates the __perf_guest_state
> static call first and __perf_guest_get_ip and the interrupt handlers
> afterwards. perf_instruction_pointer() and perf_misc_flags() test
> perf_guest_state() and then call perf_guest_get_ip().
>
> Without CONFIG_HAVE_STATIC_CALL, which arm64 selects only under CFI, a
> static call is a plain load of key->func. A PMI on another CPU can then
> see the new state callback while get_ip still resolves to the RET0
> default, and report an instruction pointer of zero for a guest sample.
>
> Install the callees first and the gate last, separated by smp_wmb(). The
> reader keeps its control dependency.
>
> Found with MBCheck, a static herd7-based memory consistency checker.
>
> Signed-off-by: Jaidev Shastri <jaidevshastri@vt.edu>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260921-mb-perf-core-v1-0-ac56a719c02b@vt.edu?part=2
next prev parent reply other threads:[~2026-09-22 1:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-22 1:13 [PATCH 0/3] perf/core: order three publications against their readers Jaidev Shastri via B4 Relay
2026-09-22 1:13 ` [PATCH 1/3] perf/core: publish the aux_event link with release semantics Jaidev Shastri via B4 Relay
2026-09-22 1:24 ` sashiko-bot
2026-09-22 1:13 ` [PATCH 2/3] perf/core: install the guest callbacks before the guest_state gate Jaidev Shastri via B4 Relay
2026-09-22 1:25 ` sashiko-bot [this message]
2026-09-22 1:13 ` [PATCH 3/3] perf/core: publish perf_event_cache with release semantics Jaidev Shastri via B4 Relay
2026-09-22 1:24 ` sashiko-bot
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