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 D32F83F482E; Thu, 16 Jul 2026 13:42:06 +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=1784209328; cv=none; b=u39qSSl/X6TczKKYisN5hhvOcbmEkN0iwE2ZRt1or36bfiUWw+0h8UzAa1fV6BoHy3BBUJNzI17VEVnDUFu60t82iMebCnLiaU+bpYNm31z08b56p52VrnQN/LTh9iXFSCSif9S5YJHBKrq73oROF6QWDfqQJIaHNtA0bFw2lcI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784209328; c=relaxed/simple; bh=Afh0/24861kPSjE8vPX5Jmg+RYHa1BKbg/mLx+azszg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=C7YhiFth2qDMcs4rm/hw5A+doiEMetPo00e0rXVoFNPdfOAY6Oav2Ni6zlfG02/y9K9xYb8QblWOS2zRgCNEjllS5JAzkfV2NGZelnbKg4txabXSG1O80r6kFz+uUlf/aoAq539w/aIqlIkuG4BNZR00dyef/2Jru3exxvJmkBc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qOrzdQFa; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qOrzdQFa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 448CB1F000E9; Thu, 16 Jul 2026 13:42:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784209326; bh=WWwQgwvyT77qNopijuVdf30vTzljQ2qzaHswKdfwyug=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=qOrzdQFaWt28334yjEhIprN7ITCjLyY0kI5BYs4aYWeXJHdf3RvWSU7WDGqA7Xlwa doZ8YJT08v75a5FnrmlBRJV9e6EOXswTrFwOyHXLPVNuVHy9A0Z7RHRL4j/LY3DD90 r8faunt1fTkIxV/gVvqEvtIzvHxYndMSZTbbcVeI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yichun Zhang , Jiri Pirko , Yuka , Ammar Faizi , "Michael S. Tsirkin" Subject: [PATCH 7.1 143/518] virtio_pci: fix vq info pointer lookup via wrong index Date: Thu, 16 Jul 2026 15:26:51 +0200 Message-ID: <20260716133050.981634948@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260716133047.772246337@linuxfoundation.org> References: <20260716133047.772246337@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ammar Faizi commit f7d380fb525c13bdd114369a1979c80c346e6abc upstream. Unbinding a virtio balloon device: echo virtio0 > /sys/bus/virtio/drivers/virtio_balloon/unbind triggers a NULL pointer dereference. The dmesg says: BUG: kernel NULL pointer dereference, address: 0000000000000008 [...] RIP: 0010:__list_del_entry_valid_or_report+0x5/0xf0 Call Trace: vp_del_vqs+0x121/0x230 remove_common+0x135/0x150 virtballoon_remove+0xee/0x100 virtio_dev_remove+0x3b/0x80 device_release_driver_internal+0x187/0x2c0 unbind_store+0xb9/0xe0 kernfs_fop_write_iter.llvm.11660790530567441834+0xf6/0x180 vfs_write+0x2a9/0x3b0 ksys_write+0x5c/0xd0 do_syscall_64+0x54/0x230 entry_SYSCALL_64_after_hwframe+0x29/0x31 [...] The virtio_balloon device registers 5 queues (inflate, deflate, stats, free_page, reporting) but only the first two are unconditional. The stats, free_page and reporting queues are each conditional on their respective feature bits. When any of these features are absent, the corresponding vqs_info entry has name == NULL, creating holes in the array. The root cause is an indexing mismatch introduced when vq info storage was changed to be passed as an argument. vp_find_vqs_msix() and vp_find_vqs_intx() store the info pointer at vp_dev->vqs[i], where 'i' is the caller's sparse array index. However, the virtqueue itself gets vq->index assigned from queue_idx, a dense index that skips NULL entries. When holes exist, 'i' and queue_idx diverge. Later, vp_del_vqs() looks up info via vp_dev->vqs[vq->index] using the dense index into the sparsely-populated array, and hits NULL. Fix this by storing info at vp_dev->vqs[queue_idx] instead of vp_dev->vqs[i], so the store index matches the lookup index (vq->index). Apply the fix to both the MSIX and INTX paths. Cc: Yichun Zhang Cc: Jiri Pirko Cc: stable@vger.kernel.org # v6.11+ Tested-by: Yuka Fixes: 89a1c435aec2 ("virtio_pci: pass vq info as an argument to vp_setup_vq()") Signed-off-by: Ammar Faizi Message-Id: <20260315141808.547081-1-ammarfaizi2@openresty.com> Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman --- drivers/virtio/virtio_pci_common.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/drivers/virtio/virtio_pci_common.c +++ b/drivers/virtio/virtio_pci_common.c @@ -423,10 +423,11 @@ static int vp_find_vqs_msix(struct virti vqs[i] = NULL; continue; } - vqs[i] = vp_find_one_vq_msix(vdev, queue_idx++, vqi->callback, + vqs[i] = vp_find_one_vq_msix(vdev, queue_idx, vqi->callback, vqi->name, vqi->ctx, false, &allocated_vectors, vector_policy, - &vp_dev->vqs[i]); + &vp_dev->vqs[queue_idx]); + queue_idx++; if (IS_ERR(vqs[i])) { err = PTR_ERR(vqs[i]); goto error_find; @@ -485,9 +486,10 @@ static int vp_find_vqs_intx(struct virti vqs[i] = NULL; continue; } - vqs[i] = vp_setup_vq(vdev, queue_idx++, vqi->callback, + vqs[i] = vp_setup_vq(vdev, queue_idx, vqi->callback, vqi->name, vqi->ctx, - VIRTIO_MSI_NO_VECTOR, &vp_dev->vqs[i]); + VIRTIO_MSI_NO_VECTOR, &vp_dev->vqs[queue_idx]); + queue_idx++; if (IS_ERR(vqs[i])) { err = PTR_ERR(vqs[i]); goto out_del_vqs;