From nobody Fri Sep 25 04:41:45 2026 Received: from cstnet.cn (smtp25.cstnet.cn [159.226.251.25]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3475F4D0CD5; Wed, 16 Sep 2026 17:26:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.25 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789579596; cv=none; b=frDSFctidlbSCZmLbNVS8EvwraGjsMuk+fUbivsfryfLoOW+hm6WVNAx+fSapjNtGENAaYARqrDfHWa775XH4gtSQzw3PK2b4o0dRshalZXbmgaGv5W4FsOqdmhOQtJ+VwHPr3If1YjSoT6fGkNhL7NbKRdxb3L0G5tCXDMI0r8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789579596; c=relaxed/simple; bh=AhpLtqGNAH+VUImvHnuwgDAzlAGIYJdklwlXZmm6V04=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=uOvxBcN34rQPkKCaiksde64+CqFTwWgvlVV1QCI7epuLujpoNGTqr0Qrxi5ALZp25P68JcvHiSnlcucJlakuZySKghKR+u2accxmq0+avxX05Bo9XiN7x47y0ehb+fWsl+O9oaxGTnMCmsDGIRdOyBeiS7zdJr2EUebH1Kw/C+c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.25 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from dfae2b116770.home.arpa (unknown [36.110.52.2]) by APP-05 (Coremail) with SMTP id zQCowADnVD9A0apqapZuCA--.23115S2; Thu, 17 Sep 2026 01:26:24 +0800 (CST) From: Wentao Liang To: airlied@gmail.com Cc: chris@chris-wilson.co.uk, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, linux-kernel@vger.kernel.org, matthew.auld@intel.com, rodrigo.vivi@intel.com, simona@ffwll.ch, tursulin@ursulin.net, Wentao Liang , stable@vger.kernel.org Subject: [PATCH] drm/i915/gt: Fix rq use-after-free in perf_mi_noop() Date: Wed, 16 Sep 2026 17:25:56 +0000 Message-Id: <20260916172556.2087724-1-vulab@iscas.ac.cn> X-Mailer: git-send-email 2.34.1 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: zQCowADnVD9A0apqapZuCA--.23115S2 X-Coremail-Antispam: 1UD129KBjvJXoWrtF4DXr48WFW8Wryktw18Zrb_yoW8JF4rpF 4rJF4YvrZxJrWIka1fJrW0vFy5Ka1SyFWxKrnrKwnxZr15X3Z5Jr1Iv3WagryUArZ7Wr43 JFs7KFW3WFnFkrJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9q14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AKxV WxJr0_GcWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2Wl Yx0E2Ix0cI8IcVAFwI0_Jw0_WrylYx0Ex4A2jsIE14v26r4j6F4UMcvjeVCFs4IE7xkEbV WUJVW8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lFIxGxcIEc7Cj xVA2Y2ka0xkIwI1lc7CjxVAaw2AFwI0_Jw0_GFyl42xK82IYc2Ij64vIr41l4I8I3I0E4I kC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWU WwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_JF I_Gr1lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4UJVWxJr1lIxAIcVCF04k26cxKx2IYs7xG 6r1j6r1xMIIF0xvEx4A2jsIE14v26r4j6F4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr1j6F 4UJbIYCTnIWIevJa73UjIFyTuYvjfU5byZUUUUU X-CM-SenderInfo: pyxotu46lvutnvoduhdfq/1tbiCRIMA2qqozVqnAAAs0 Content-Type: text/plain; charset="utf-8" The i915_request_put() after the wait may drop the final reference and free the request, yet the following cycle counting still reads rq->hwsp_seqno. Compute the cycles[] entry while the reference taken before i915_request_add() is still held. Fixes: 3c7a44bbbfa7 ("drm/i915/selftests: Perform some basic cycle counting= of MI ops") Cc: stable@vger.kernel.org Signed-off-by: Wentao Liang --- drivers/gpu/drm/i915/gt/selftest_engine_cs.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/selftest_engine_cs.c b/drivers/gpu/drm= /i915/gt/selftest_engine_cs.c index 5ffa5e30f419..7503763136b2 100644 --- a/drivers/gpu/drm/i915/gt/selftest_engine_cs.c +++ b/drivers/gpu/drm/i915/gt/selftest_engine_cs.c @@ -351,13 +351,14 @@ static int perf_mi_noop(void *arg) =20 if (i915_request_wait(rq, 0, HZ / 5) < 0) err =3D -EIO; + if (err =3D=3D 0) + cycles[i] =3D + (rq->hwsp_seqno[4] - rq->hwsp_seqno[3]) - + (rq->hwsp_seqno[3] - rq->hwsp_seqno[2]); + i915_request_put(rq); if (err) break; - - cycles[i] =3D - (rq->hwsp_seqno[4] - rq->hwsp_seqno[3]) - - (rq->hwsp_seqno[3] - rq->hwsp_seqno[2]); } i915_vma_put(nop); i915_vma_put(base); --=20 2.34.1