From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 13FB1378823 for ; Tue, 13 Oct 2026 08:23:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791879827; cv=none; b=iEreiuZrNqKJdMdiO14c1DXdseJyhIzhzxaxoI6XOamvLZ+sycIKEbg7eSDI60h9Lz+AQJ9aYKVJ3wCGDmxVWVA/KABO+KIrPVrGc0tpEGBAa35NCMKe+4gkXvLf0xOEKMFJd1VHOqdBGWOh1UxaDx+mFO9jyQYkHUxbQlmjV9w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791879827; c=relaxed/simple; bh=fAcMBbd51bcHOwBKLc4xecUv4PeZoMB+rndwybCc7/M=; h=Message-ID:From:Subject:To:Cc:In-Reply-To:References:Content-Type: Date; b=Ha0m8u/tEfuSViuA0AbFn9JTKcw1lS4wEsL4+H8Bzt8ygoT5SXizGat+2Vatd+ilTcgPtT2VOx2rQlAALAFvrK9IEnxDXQ3LKcqejkBS0nyeAGwj+1nE0SKMzo52P4oVviENu8rK9NhtfmSdFOVJzZePFtLVEe9y5WQFK7+7OKI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oT04mpqL; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oT04mpqL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 80B161F000FF; Tue, 13 Oct 2026 08:23:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791879825; bh=b43DpWIjNb9nYYUi5wnsXjXRUS/49g28vMPfOTz0kmc=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=oT04mpqLjMeFRO8PoNYuk4rTIP0u6V3ICOJV68IgaOOWPNln9gQRliRPJ9S6Kop2V OK637G+K6FHi+EZjwSu7tmP8yO35ej+u/1pqYK3/qNrFWfGRReEJ/bKhFojcKkuSo+ jhHpiB1kKgaXdyRxRLP+LbzK5IJi6SY2bjagGnh81bj5L7GrulS5Yh9j3zuEt2+T5I fhhvAbU+pq2zNh/kuOyTwoBLja3RuUCuM1VzXk+ViG/VYGse6KtdNX+9jqk6n7J1tE IQHfF3pq5DJ18rx+EFj+sJOJ/KGgzxRq2f8cOUcAgs0mYrr90r2Loq3WtCAqq5OZHP +Df0nfjmBpujA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH] perf/x86: Don't WARN when the ext_regs_buf allocation fails Reply-To: sashiko-reviews@lists.linux.dev To: vineash Cc: linux-perf-users@vger.kernel.org In-Reply-To: <179187920064.3441876.15687522011658301558@gmail.com> References: <179187920064.3441876.15687522011658301558@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 13 Oct 2026 08:23:45 +0000 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > reserve_ext_regs_buffers() wraps the per-CPU ext_regs_buf allocation in > WARN_ON_ONCE(). The allocator already prints a warning with a stack dump > when a GFP_KERNEL allocation fails, so the WARN only repeats it, which > Documentation/process/coding-style.rst asks not to do. The failure is > also handled: the buffers are freed again, the event is still created, > and events that ask for SIMD or extended register sampling are rejected > with -ENOMEM in x86_pmu_hw_config() and event_simd_regs_validate(). >=20 > syzkaller hit this with fault injection on next-20261002. The trigger > is a plain hardware cycles event opened while no other x86 PMU event > exists, with the allocation failed: >=20 > !per_cpu(ext_regs_buf, cpu) > WARNING: arch/x86/events/core.c:441 at reserve_ext_regs_buffers arch/x8= 6/events/core.c:441 [inline] > WARNING: arch/x86/events/core.c:441 at x86_reserve_hardware+0x6ff/0x880= arch/x86/events/core.c:458 > [ ... ] > warning. >=20 > Fixes: b84c96283684 ("perf/x86: Enable XMM register sampling for non-PEBS= events") > Assisted-by: Claude:claude-opus-5-5 syzkaller > Signed-off-by: vineash Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/179187920064.344187= 6.15687522011658301558@gmail.com?part=3D1