From nobody Fri Sep 25 04:41:46 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 B2DBE36D503; Wed, 16 Sep 2026 17:29:20 +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=1789579763; cv=none; b=T5Hh77LAjRM9etXOydgE01UwvCWZ5iTF363L/uDu4+IskVxbyD0d/qtfGt+Y6hzpVmH/sw2VYKwIAPHMOGG8c8I5Kg1COEs/qjmybQpCgUDFx5TRKN4b9Tgy0i0q5gZw6O2baM5vaD9CdJkhnVfqhZEy3++AleWaPnpoHCym/bU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789579763; c=relaxed/simple; bh=3F+/Vfhc8Rh0Xlo8+0M6by/0bTS+n5+7+zjCYGeHuOw=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=kZ05GOdhB2cxI88dDTPIONG3myeIUNjxjkpvIkneIbedVa8KOyNv0W+GmME+rJsCtjj62ZtFUB8X1iRE1DhxATYR41s2tOLw7DfTQf+dDpbGrAMhf/Ue7naISIJQh6T1Ur6fkdRQT7jQuvF9ZGCvIu2P95K3oUyavhlz3fNCnpA= 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 zQCowACXAj3o0apquZ9uCA--.22432S2; Thu, 17 Sep 2026 01:29:12 +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, 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 signal_irq_work() Date: Wed, 16 Sep 2026 17:28:44 +0000 Message-Id: <20260916172844.2087895-1-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: zQCowACXAj3o0apquZ9uCA--.22432S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Ww4xuFy8AFykury3trW5ZFb_yoW8Ww4Dpr 43JFyYyrZ8ZFnFv3WrC3W8CF4fWa42yF1UWF98G3s3Jwn8tas3Ar9YvFyjqFyY9rs3Xw1q qryqqrW7WFWUZr7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 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/1tbiBwIMA2qqpVhjkQAAsF Content-Type: text/plain; charset="utf-8" The final i915_request_put() can release the last reference to a signaled request, freeing it synchronously (kmem_cache_free) before the RCU iterator advances to read rq->signal_link.next. Grab the next request up front, so the loop does not touch a request that may already have been freed. Fixes: c744d50363b7 ("drm/i915/gt: Split the breadcrumb spinlock between gl= obal and contexts") Cc: stable@vger.kernel.org Signed-off-by: Wentao Liang --- drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/= i915/gt/intel_breadcrumbs.c index f840e98792cd..90bc32b526b8 100644 --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c @@ -213,7 +213,7 @@ static void signal_irq_work(struct irq_work *work) for (ce =3D list_first_or_null_rcu(&b->signalers, typeof(*ce), signal_lin= k); ce; ce =3D cn) { - struct i915_request *rq; + struct i915_request *rq, *rn; =20 /* * Grab the next signaler up front, as dropping the final @@ -223,9 +223,16 @@ static void signal_irq_work(struct irq_work *work) cn =3D list_next_or_null_rcu(&b->signalers, &ce->signal_link, typeof(*cn), signal_link); =20 - list_for_each_entry_rcu(rq, &ce->signals, signal_link) { + for (rq =3D list_first_or_null_rcu(&ce->signals, + typeof(*rq), signal_link); + rq; + rq =3D rn) { bool release; =20 + rn =3D list_next_or_null_rcu(&ce->signals, + &rq->signal_link, + typeof(*rn), signal_link); + if (!__i915_request_is_complete(rq)) break; =20 --=20 2.34.1