From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794272456; b=JS/RkMKDRzbBsodP4t0lqi4NgpudVszrpX35ZO5qD4vuRqXl/34Qfn86G2lSSq6t19KY fGELg7S65u0IpdYRjD//CVUtFXjHyDpbKpE0IE3/YBaT4owAiepgDXSi8AuwHuKzvmZYO IqKQB26RbvMkVUPavlxA1/d7I7h1yHP/7z4QvZAlt4YKCRHqXVrzczhWVNX0Tw56Y07hJ z3KjHpypXW3LrXgJVYkk81ESezudnn/KccLOEHkXYzUzMrUtCqrDg26gMZMIuvmA4itOp JI9nh20Vsqd4KKocggM7c3ADarwXCiqM4OYXNH/pz5eRguf5CVDxtPrm87HxairgoZw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794272456; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=q/xp3ksJitjsyBHsKTRktsqG+iWF66HxAT19HfbKGtY=; b=g1EfRlo0FbndtZmx1LNbyUJck3eKX1GyN0IThn7ZTlX/cdCgWqqO9ZHYutYaNDR8gHA5 +Qkqmut/dRzgFRXsDQDktcnEyj6bAr9uQja1jUmYK1ooxJWeaC3lm3AEFmwzDyn+3pW2i OaVGSw75BsmJt/BldrSoVty3G6ME5ZZIfssA1F83VvIRDIvhSSdWRbkv6lz4PmntNCp5R +vxMHQ/u3u+KtWk7y2aImFuEErUsvvnnHMRn7gh8//bqU/wyKDQdIcEosSrE8sGDbARvj oEs+ywcvYHk6ti+OpnUGl/9ADVXhnTZmnFFCJcxs/9kR7ORJMmuEd9KPHLK1svgfQ6Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=L+6PVagd; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 83518606A321 for ; Tue, 10 Nov 2026 01:00:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=L+6PVagd Received: by smtp.kernel.org (Postfix) with ESMTPSA id 793311F0089F; Tue, 10 Nov 2026 01:00:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794272456; bh=q/xp3ksJitjsyBHsKTRktsqG+iWF66HxAT19HfbKGtY=; h=From:To:Cc:Subject:Date; b=L+6PVagdcuoJMyx+UgP3HajlNMsPc6Qu5+znp4W70iRgAWSdXR5En101wQCd7Jqhn ARN2CElQOW+U35LXwBZxXPwMSVDLVFStHbHrXN43uQdNpgTL3tOQQe57cUDCuz0YCT Q+oUcw/4n6USA+1aCYZPpQJ+tOH6ktriBQssQfk04ou4jCaO6Wgx+UHzG8qvei9/95 qmZ6HhwqJVjMnUqMaUUTpSRj1+EkMZ+A0Qvv/l/kHkPKjU2xt01rHf3/1BxhYd6tQn ko0LrQVsWGLtBInVUG6YxKVL5xUUjAKfejG/TXvkP/B4sLbHVWzU2vdYVtNiW1eUXv O1nxz4NZpfA1Q== From: Sasha Levin To: zhaoyz24@mails.tsinghua.edu.cn, yangyx22@mails.tsinghua.edu.cn, wangao@seu.edu.cn, fengxw06@126.com, qli01@tsinghua.edu.cn, xuke@tsinghua.edu.cn, asmadeus@codewreck.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] 9p/xen: drain response work after unbinding IRQ" failed to apply to 7.3-stable tree Date: Mon, 9 Nov 2026 20:00:54 -0500 Message-ID: <20261109200054-failed-7.3-7b6f2e3c29fb@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 7.3-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-7.3.y git checkout FETCH_HEAD git cherry-pick -x 7b6f2e3c29fb4d76f1e4973280792eabbd526602 # git commit -s git send-email --to '' --in-reply-to '20261109200054-failed-7.3-7b6f2e3c29fb@kernel.org' --subject-prefix 'PATCH 7.3.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 7b6f2e3c29fb4d76f1e4973280792eabbd526602 Mon Sep 17 00:00:00 2001 From: Yizhou Zhao Date: Tue, 9 Jun 2026 23:52:01 +0800 Subject: [PATCH] 9p/xen: drain response work after unbinding IRQ commit ea4f1009408e ("9p/xen : Fix use after free bug in xen_9pfs_front_remove due to race condition") added cancel_work_sync() to keep xen_9pfs_front_free() from freeing a ring while p9_xen_response() is still running. The work is currently drained before the event channel IRQ is unbound. That leaves a race window where xen_9pfs_front_event_handler() can run after cancel_work_sync() returns and queue p9_xen_response() again. The following unbind_from_irqhandler() synchronizes with the IRQ handler, but it does not cancel work that the handler already queued. The teardown can then free the ring and private data while the response work remains pending, and the worker later dereferences ring->priv and priv->client. Unbind the event channel IRQ before draining the work. Once the IRQ is unbound, no new response work can be queued by the backend event channel, and cancel_work_sync() waits for any work that was queued before or during the unbind. It is then safe to release the ring resources. Fixes: ea4f1009408e ("9p/xen : Fix use after free bug in xen_9pfs_front_remove due to race condition") Cc: stable@vger.kernel.org Reported-by: Yizhou Zhao Reported-by: Yuxiang Yang Reported-by: Ao Wang Reported-by: Xuewei Feng Reported-by: Qi Li Reported-by: Ke Xu Assisted-by: GLM:GLM-5.1 Signed-off-by: Yizhou Zhao Message-ID: <20260609155202.1706-1-zhaoyz24@mails.tsinghua.edu.cn> Signed-off-by: Dominique Martinet --- net/9p/trans_xen.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c index 5a0b5b83e8ab4..9ee1ac9143d43 100644 --- a/net/9p/trans_xen.c +++ b/net/9p/trans_xen.c @@ -282,14 +282,14 @@ static void xen_9pfs_front_free(struct xen_9pfs_front_priv *priv) for (i = 0; i < XEN_9PFS_NUM_RINGS; i++) { struct xen_9pfs_dataring *ring = &priv->rings[i]; - cancel_work_sync(&ring->work); - if (!ring->intf) break; if (ring->irq >= 0) { unbind_from_irqhandler(ring->irq, ring); ring->irq = -1; } + cancel_work_sync(&ring->work); + if (ring->data.in) { for (j = 0; j < (1 << ring->intf->ring_order); j++) { grant_ref_t ref; -- 2.53.0