From: Hang Zhengyang <hang.zhengyang1010@gmail.com>
To: Zhao Gongyi <zhaogongyi@bytedance.com>
Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
namhyung@kernel.org, mark.rutland@arm.com,
alexander.shishkin@linux.intel.com, jolsa@kernel.org,
irogers@google.com, adrian.hunter@intel.com,
james.clark@linaro.org, x86@kernel.org, kim.phillips@amd.com,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf/x86: Reject pair-counter groups with no GP budget
Date: Thu, 12 Nov 2026 10:40:24 +0800 [thread overview]
Message-ID: <20261112024027.3678221-1-hang.zhengyang1010@gmail.com> (raw)
In-Reply-To: <20261109110356.27709-1-zhaogongyi@bytedance.com>
On Mon, 09 Nov 2026 19:03:56 +0800, Zhao Gongyi wrote:
> AMD large-increment events reserve an extra GP counter. A syzkaller
> reproducer opens a perf event group until the adjusted GP budget is
> exhausted. x86_schedule_events() then WARNs on the unschedulable group.
Tested on AMD Zen 3 (KVM guest, tip perf/urgent): a group of six
fp_ret_sse_avx_ops.all events hits the WARN without this patch and not
with it; smaller groups still schedule. Without your n_pair fix the WARN
fires only once per CPU.
Tested-by: Hang Zhengyang <hang.zhengyang1010@gmail.com>
prev parent reply other threads:[~2026-11-12 2:40 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-09 11:03 Zhao Gongyi
2026-11-12 2:40 ` Hang Zhengyang [this message]
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