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=1793802064; b=IQqLhRAvlPPLxXrfeDscmmCsf91/zVUAYBkCWAuxWJKD8fmaq0OP0h2tx21643DXwcKq OqXMel7Sn5VhFB5lRONqioAxx19d1gCrsJdQMvYGCOxPJ16rALScbSNA9J4RdHL5Xy8Eu Tgwc3FwuV/54NNddH/3aFPXH6n78lvmJryrTpBaBnr11WeKDF7G/p07NblQ9pNtCSV0uG pjPsiDkbq6UB4hhUfFyyiVLrKukQ9LdOJKWQquLzCmGeu+lZ0mVzca9bm5qlbjvaPEPNR AnzToOZdTwFO5bMJDbS1mqgugMJTeCZbOffbcmPyaLSQeeiCvGuMtmZikIrYwni4BKQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793802064; h=Received:DKIM-Signature:Subject:To:Cc:From:Date:Message-ID: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=5TqdAsohJ31BORasylPmoQEIIhqMVLuFGJn/C5twEpA=; b=ARNhidlv/kIhzyUB0k7DjpEti61MNqDqfpcS1gYFs1tsZvqqLx4/Q2j2oY9dpIl2aXgJ E/NP/DVyp0O78v+qdhuZH0H/QfLMsB1AliAgoXPM59vi9jpFqfEfPNasD28FkpZsGJ+ee cT4RLswdpdWYndkcMpQ99KZ3hlHsoOAiP3IO8GDV2cGkbnWB7wou5yRMhCd5r4AhM+aLu sn171Nimd10msasaLOskwcZABbgHdfNHsjJayqYnMgLCk1yvn1xO6f7hqqanuMRhxKRPw dYUnNPhQ+51fREtuUc4d96tHOo5pB52KQGxPEIgvDuCSl1eXaQ6WG0Z2TOqJEOw7H3g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=D8Tc2Mro; 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 4282E606A31B for ; Wed, 4 Nov 2026 14:21:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=D8Tc2Mro Received: by smtp.kernel.org (Postfix) with ESMTPSA id CE3201F000C1; Wed, 4 Nov 2026 14:21:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793802064; bh=5TqdAsohJ31BORasylPmoQEIIhqMVLuFGJn/C5twEpA=; h=Subject:To:Cc:From:Date; b=D8Tc2MroFwIGxtwlbjce+zGbUDF8EU8UgGk23B2eK49AdyuclzfwDbAEc4xu1x/OY dGruDW6RuPbhzg78aX7qUoiDCgjFsaYrRQQTcnGbTdmaE0CMQw874edLEsZIT4DJHV kot4gVZT7FqxI4pFCscE4A9kpzs1Drf0zBZRmYRI= Subject: FAILED: patch "[PATCH] xen-blkfront: unbind irq before tearing down ring and shadow" failed to apply to 5.15-stable tree To: ndaugoing@gmail.com,jgross@suse.com,roger@xenproject.org Cc: From: Date: Wed, 04 Nov 2026 15:21:02 +0100 Message-ID: <2026110402-division-regulate-7540@gregkh> 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 5.15-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-5.15.y git checkout FETCH_HEAD git cherry-pick -x f3e27b7955727a4d7c0e9264a2a209fbba788bdc # git commit -s git send-email --to '' --in-reply-to '2026110402-division-regulate-7540@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From f3e27b7955727a4d7c0e9264a2a209fbba788bdc Mon Sep 17 00:00:00 2001 From: Yuchao Zhang Date: Tue, 22 Sep 2026 15:21:55 +0800 Subject: [PATCH] xen-blkfront: unbind irq before tearing down ring and shadow requests MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In blkif_free_ring(), the driver tears down the ring's persistent grants, shadow request arrays, and shared ring structure (xenbus_teardown_ring), and only calls unbind_from_irqhandler() at the very end. While blkif_free_ring() is freeing persistent grants and clearing the shadow array, the event channel interrupt (blkif_interrupt) is still registered and active. If an interrupt arrives from the backend during this teardown window, blkif_interrupt() reads rinfo->ring.sring and, via blkif_completion(), accesses rinfo->shadow[id].grants_used and rinfo->shadow[id].sg. blkif_free_ring() tears these structures down without holding rinfo->ring_lock, and the handler only checks info->connected at entry, so this is a real race resulting in a use-after-free or NULL pointer dereference. Fix this by moving unbind_from_irqhandler() to the beginning of blkif_free_ring(). Calling unbind_from_irqhandler() first frees the IRQ and synchronizes with any in-flight interrupt handlers on other CPUs before ring memory and shadow request structures are deallocated, matching the teardown order in drivers/net/xen-netfront.c. Fixes: 11659569f720 ("xen/blkfront: split per device io_lock") Cc: stable@vger.kernel.org Signed-off-by: Yuchao Zhang Acked-by: Roger Pau Monné Signed-off-by: Juergen Gross Message-ID: <20260922072155.34625-1-ndaugoing@gmail.com> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 8dad7bf5f664..86f5dd3aced1 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1210,6 +1210,14 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo) struct blkfront_info *info = rinfo->dev_info; int i, j, segs; + /* + * Interrupt teardown must be done ahead of freeing queue-related + * data, otherwise the interrupt handler can race with the cleanup. + */ + if (rinfo->irq) + unbind_from_irqhandler(rinfo->irq, rinfo); + rinfo->evtchn = rinfo->irq = 0; + /* * Remove indirect pages, this only happens when using indirect * descriptors but not persistent grants @@ -1292,10 +1300,6 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo) /* Free resources associated with old device channel. */ xenbus_teardown_ring((void **)&rinfo->ring.sring, info->nr_ring_pages, rinfo->ring_ref); - - if (rinfo->irq) - unbind_from_irqhandler(rinfo->irq, rinfo); - rinfo->evtchn = rinfo->irq = 0; } static void blkif_free(struct blkfront_info *info, int suspend)