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 E142149F10A for ; Wed, 9 Sep 2026 09:58:03 +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=1788947885; cv=none; b=owwy334ZWS2kjUt1veT82eOvDeC/51tO5ghbHwc5iNCpfOzZwfYoe19QOaTt+ycKhjoq92r8zwz3eOYHWVnh+naooc1cdG4RNmWIbxarFMh46Er4YE7JuYI9WLqBfe2RzoQZJtCP57ALWX3w2RN/sMxQCH/muZzUthyv1SWVF2M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788947885; c=relaxed/simple; bh=pn/A+5THkkyBsV3dvfj9fb19RjJSY/5afzAf9I2JpZ0=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=SPjrejVDKw/56BcRPUm3IASvomWVUp4h+sXaGdHASLrslGlXLk0hf7fgnyCDNHwRpeBH4k59i1msqramEe7qoaJvtivIMAwDPM7K71NWOOYxCfXXmnwQwcEgbJDm3V3L+SlmmKOsz3Naf8eWusaxEsHyWR4rGq+9RtaC3tD+vR4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ZTPIUE/A; 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="ZTPIUE/A" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4696D1F00A3A; Wed, 9 Sep 2026 09:58:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788947883; bh=ZinVxtiZrEUybcZ2CdMzJR4S6SzWcIW2PlsNfsxTV0s=; h=Subject:To:Cc:From:Date; b=ZTPIUE/AKPAhs7c07pTBXylyctdZLJ7dOnCrqaYC9FT84SpBv8n8LVal4iwgrLONM hRjwebSw0HXizH8kTZlzxeXeF28hrKqicIKklPR6+SWWck8vPoNWRb86JsMT3jssBf Nhb3NzZS3OMWGRr8lpeEYzhUsK6odAbaHhhadnCg= Subject: FAILED: patch "[PATCH] nvdimm: virtio_pmem: refcount requests for token lifetime" failed to apply to 6.6-stable tree To: me@linux.beauty,mst@redhat.com Cc: From: Date: Wed, 09 Sep 2026 11:51:39 +0200 Message-ID: <2026090939-disdain-corridor-626c@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-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-6.6.y git checkout FETCH_HEAD git cherry-pick -x e57140944b5a47a7fd5a142faab29a02af040bc8 # git commit -s git send-email --to '' --in-reply-to '2026090939-disdain-corridor-626c@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From e57140944b5a47a7fd5a142faab29a02af040bc8 Mon Sep 17 00:00:00 2001 From: Li Chen Date: Tue, 30 Jun 2026 17:23:33 +0800 Subject: [PATCH] nvdimm: virtio_pmem: refcount requests for token lifetime KASAN reports slab-use-after-free in __wake_up_common(): BUG: KASAN: slab-use-after-free in __wake_up_common+0x114/0x160 Read of size 8 at addr ffff88810fdcb710 by task swapper/0/0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.19.0-next-20260220-00006-g1eae5f204ec3 #4 PREEMPT(full) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.17.0-2-2 04/01/2014 Call Trace: dump_stack_lvl+0x6d/0xb0 print_report+0x170/0x4e2 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 ? __virt_addr_valid+0x1dc/0x380 kasan_report+0xbc/0xf0 ? __wake_up_common+0x114/0x160 ? __wake_up_common+0x114/0x160 __wake_up_common+0x114/0x160 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 __wake_up+0x36/0x60 virtio_pmem_host_ack+0x11d/0x3b0 ? sched_balance_domains+0x29f/0xb00 ? __pfx_virtio_pmem_host_ack+0x10/0x10 ? _raw_spin_lock_irqsave+0x98/0x100 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 vring_interrupt+0x1c9/0x5e0 ? __pfx_vp_interrupt+0x10/0x10 vp_vring_interrupt+0x87/0x100 ? __pfx_vp_interrupt+0x10/0x10 __handle_irq_event_percpu+0x17f/0x550 ? __pfx__raw_spin_lock+0x10/0x10 handle_irq_event+0xab/0x1c0 handle_fasteoi_irq+0x276/0xae0 __common_interrupt+0x65/0x130 common_interrupt+0x78/0xa0 virtio_pmem_host_ack() wakes a request that has already been freed by the submitter. This happens when the request token is still reachable via the virtqueue, but virtio_pmem_flush() returns and frees it. Fix the token lifetime by refcounting struct virtio_pmem_request. virtio_pmem_flush() holds a submitter reference, and the virtqueue holds an extra reference once the request is queued. The completion path drops the virtqueue reference, and the submitter drops its reference before returning. Fixes: 6e84200c0a29 ("virtio-pmem: Add virtio pmem driver") Cc: stable@vger.kernel.org Signed-off-by: Li Chen Signed-off-by: Michael S. Tsirkin Message-ID: <20260630092338.2094628-9-me@linux.beauty> diff --git a/drivers/nvdimm/nd_virtio.c b/drivers/nvdimm/nd_virtio.c index 8c0d4347938a..1cf53f75b128 100644 --- a/drivers/nvdimm/nd_virtio.c +++ b/drivers/nvdimm/nd_virtio.c @@ -15,6 +15,14 @@ struct virtio_pmem_flush_work { struct bio *bio; }; +static void virtio_pmem_req_release(struct kref *kref) +{ + struct virtio_pmem_request *req; + + req = container_of(kref, struct virtio_pmem_request, kref); + kfree(req); +} + static void virtio_pmem_wake_one_waiter(struct virtio_pmem *vpmem) { struct virtio_pmem_request *req_buf; @@ -42,6 +50,7 @@ void virtio_pmem_host_ack(struct virtqueue *vq) virtio_pmem_wake_one_waiter(vpmem); WRITE_ONCE(req_data->done, true); wake_up(&req_data->host_acked); + kref_put(&req_data->kref, virtio_pmem_req_release); } spin_unlock_irqrestore(&vpmem->pmem_lock, flags); } @@ -72,6 +81,7 @@ static int virtio_pmem_flush(struct nd_region *nd_region) if (!req_data) return -ENOMEM; + kref_init(&req_data->kref); WRITE_ONCE(req_data->done, false); init_waitqueue_head(&req_data->host_acked); init_waitqueue_head(&req_data->wq_buf); @@ -89,10 +99,23 @@ static int virtio_pmem_flush(struct nd_region *nd_region) * to req_list and wait for host_ack to wake us up when free * slots are available. */ - while ((err = virtqueue_add_sgs(vpmem->req_vq, sgs, 1, 1, req_data, - GFP_ATOMIC)) == -ENOSPC) { + for (;;) { + err = virtqueue_add_sgs(vpmem->req_vq, sgs, 1, 1, req_data, + GFP_ATOMIC); + if (!err) { + /* + * Take the virtqueue reference while @pmem_lock is + * held so completion cannot run concurrently. + */ + kref_get(&req_data->kref); + break; + } - dev_info(&vdev->dev, "failed to send command to virtio pmem device, no free slots in the virtqueue\n"); + if (err != -ENOSPC) + break; + + dev_info_ratelimited(&vdev->dev, + "failed to send command to virtio pmem device, no free slots in the virtqueue\n"); WRITE_ONCE(req_data->wq_buf_avail, false); list_add_tail(&req_data->list, &vpmem->req_list); spin_unlock_irqrestore(&vpmem->pmem_lock, flags); @@ -101,6 +124,7 @@ static int virtio_pmem_flush(struct nd_region *nd_region) wait_event(req_data->wq_buf, READ_ONCE(req_data->wq_buf_avail)); spin_lock_irqsave(&vpmem->pmem_lock, flags); } + err1 = virtqueue_kick(vpmem->req_vq); spin_unlock_irqrestore(&vpmem->pmem_lock, flags); /* @@ -116,7 +140,7 @@ static int virtio_pmem_flush(struct nd_region *nd_region) err = le32_to_cpu(req_data->resp.ret); } - kfree(req_data); + kref_put(&req_data->kref, virtio_pmem_req_release); return err; }; diff --git a/drivers/nvdimm/virtio_pmem.h b/drivers/nvdimm/virtio_pmem.h index e6dfc10ce076..3af92588bd9d 100644 --- a/drivers/nvdimm/virtio_pmem.h +++ b/drivers/nvdimm/virtio_pmem.h @@ -12,12 +12,14 @@ #include #include +#include #include #include #include #include struct virtio_pmem_request { + struct kref kref; struct virtio_pmem_req req; struct virtio_pmem_resp resp;