From nobody Sat Feb 7 09:30:27 2026 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.3]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 580D13211; Tue, 3 Jun 2025 03:27:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.3 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748921261; cv=none; b=Q8DeUaZpKldM/eHW1XdekYsDpVLzqRhHCLs7QJ4nY8iSYiL3bhJKKLMW+ziAH+ttZ1FBWFNu6yMsFbM5rBTL2TqWlX4IMbMPE4oiOCvEA+th1vspVDNvrtDaPQUmIz26W0QiOvr22yuYxl0kVjhBEfuPHhYKe1xnNX+cNmCagh0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748921261; c=relaxed/simple; bh=qoOBDlUPF7WsnUb9ArxRohE398Vyf46FNJjRMK9clAA=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=MrpwvjHhkRxURy+3+hMp6GiGv7sYTTQ8F2Zc1utO99LMEvPun2nvKq5WO8AIcKJRmPeXPB8bd2MqsIUBYE3agwhXuie1zMzo88M3ad+X9RMEArYsk3Yy/ivfU9XAJXPQfPp7ZMum20NCnzzr1Ei8OYxnUOo0sd4PnsDjIhwibpk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=JSzHk9X5; arc=none smtp.client-ip=117.135.210.3 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="JSzHk9X5" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=oQ j/8FWq0vvPTv9DKxvy8u85jrpI3Px81QRZ6pou8UU=; b=JSzHk9X5+HM8QrBYIQ behw/C08422zihPrdqAWEeym4xmZ8K2Q13wHhkWYSAoQWEPmLGuBk23GFuUhEvcp Qrl1EUE0X1SQUW1vopbD5pLUPkbIbK58JUJqabroSc6EXN+hbOgLkn23vGSVpidQ 6Nr2Xu3cuWwEmoYsZIHWJvF68= Received: from localhost.localdomain (unknown []) by gzga-smtp-mtada-g1-0 (Coremail) with SMTP id _____wCX70x8az5o6vFIGA--.18825S4; Tue, 03 Jun 2025 11:27:09 +0800 (CST) From: David Wang <00107082@163.com> To: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, mingo@kernel.org, yeoreum.yun@arm.com Cc: leo.yan@arm.com, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, David Wang <00107082@163.com> Subject: [PATCH] perf/core: restore __perf_remove_from_context when DETACH_EXIT not set Date: Tue, 3 Jun 2025 11:26:51 +0800 Message-Id: <20250603032651.3988-1-00107082@163.com> X-Mailer: git-send-email 2.39.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wCX70x8az5o6vFIGA--.18825S4 X-Coremail-Antispam: 1Uf129KBjvJXoW7AF4ftw15uFy3Xw4kAF1DWrg_yoW8Kw1kpw s7CrnxK3y0q34qvw43tr1kWwn8Cw4kJa90q3WDKw13XFWrXrZ8XF1xKFW3Zr4Yyr92qa47 tw4Ig3W2g3yqka7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0JUUhL8UUUUU= X-CM-SenderInfo: qqqrilqqysqiywtou0bp/1tbiqBlhqmg+WcTy7QABsv Content-Type: text/plain; charset="utf-8" commit a3c3c66670ce ("perf/core: Fix child_total_time_enabled accounting bug at task exit") made changes to __perf_remove_from_context() to coordinate its changes with perf_event_exit_event(), but the change are unconditional, it impacts callpaths to __perf_remove_from_context() other than from perf_event_exit_event(). One of the impact is to cgroup, which is not properly handled and would cause kernel panic with high probalibity during reboot on some system[1]. To confine the side effects, make the changes to __perf_remove_from_context() conditional, restore to its previous state except when DETACH_EXIT is set. Closes: https://lore.kernel.org/lkml/20250601173603.3920-1-00107082@163.com= / [1] Fixes: a3c3c66670ce ("perf/core: Fix child_total_time_enabled accounting bu= g at task exit") Signed-off-by: David Wang <00107082@163.com> --- kernel/events/core.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 95e703891b24..6a7e3f5c5af5 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2466,7 +2466,7 @@ __perf_remove_from_context(struct perf_event *event, void *info) { struct perf_event_pmu_context *pmu_ctx =3D event->pmu_ctx; - enum perf_event_state state =3D PERF_EVENT_STATE_OFF; + enum perf_event_state exit_state =3D PERF_EVENT_STATE_EXIT; unsigned long flags =3D (unsigned long)info; =20 ctx_time_update(cpuctx, ctx); @@ -2475,19 +2475,20 @@ __perf_remove_from_context(struct perf_event *event, * Ensure event_sched_out() switches to OFF, at the very least * this avoids raising perf_pending_task() at this time. */ - if (flags & DETACH_EXIT) - state =3D PERF_EVENT_STATE_EXIT; if (flags & DETACH_DEAD) { event->pending_disable =3D 1; - state =3D PERF_EVENT_STATE_DEAD; + exit_state =3D PERF_EVENT_STATE_DEAD; } event_sched_out(event, ctx); - perf_event_set_state(event, min(event->state, state)); + if (flags & DETACH_EXIT) + perf_event_set_state(event, min(event->state, exit_state)); if (flags & DETACH_GROUP) perf_group_detach(event); if (flags & DETACH_CHILD) perf_child_detach(event); list_del_event(event, ctx); + if (flags & DETACH_DEAD) + event->state =3D PERF_EVENT_STATE_DEAD; =20 if (!pmu_ctx->nr_events) { pmu_ctx->rotate_necessary =3D 0; --=20 2.39.2