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 C2FFE3A1687; Sat, 12 Sep 2026 07:05:29 +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=1789196731; cv=none; b=YuUc5yzEAMOC/VNNzyrAKLm+80ktxLP5FjCtfo9ggbVekQAyzOdl4vyW5VfFFY3N4/u3sJJf7a903yRd+yrZDBXmuMiI4iSlYEo87FYnzByujSV1eRnI/lsQZgyQsu9vIZW90zLuolGglkRc0hfGSpvWDbDVjjX/yO7jBqQCwyM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789196731; c=relaxed/simple; bh=VkC1FS3v2s+bMBoqllLRTXIpjpGVhFeK/9dM7xWCgN8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=T67mHOpQohLOmRFrIxy2mmVbsMlVbTqvsbYG2/OZf2VijXS8G48WDU4Ik/H//9d+Yy1397CaPEzpoFinKkNDeFOJmZWwgrnlx288sjvp33n+RsReIXDZRfithoi9BeeS08XuqkFJ1RHSlIiqe7zAsHTHXt6Q3AeL44kbcguOeTQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=uV3o1WuG; 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="uV3o1WuG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8BCCB1F00893; Sat, 12 Sep 2026 07:05:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789196728; bh=4qMyetjobLKQVmUCGlytbbezooNbAFvp5rdzbp0oZBU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=uV3o1WuGAeYlnCV1EU2uoOnjmS8L3+ut1bIs7kiL1b4LpIAo2lfJd6nqHETH3okVD JCAuNT156fjMhX2qyB9SOSVZZCZRQe3hrf14gCTD0ySno9RZe9J6QBcAf6MYudowJe uDJ9F1qvwrRmJ9+x1/Hrc402T9Fqzj5pMOuPDZJE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pankaj Gupta , Li Chen , "Michael S. Tsirkin" , Sasha Levin Subject: [PATCH 7.2 0025/1815] nvdimm: virtio_pmem: use READ_ONCE()/WRITE_ONCE() for wait flags Date: Sat, 12 Sep 2026 08:29:35 +0200 Message-ID: <20260912065649.597716071@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065648.999753832@linuxfoundation.org> References: <20260912065648.999753832@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 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Li Chen [ Upstream commit 08e72a5ba1ab9dc0adf993ff0f4d606a1e3445a8 ] Use READ_ONCE()/WRITE_ONCE() for the wait_event() flags (done and wq_buf_avail). They are observed by waiters without pmem_lock, so make the accesses explicit single loads/stores and avoid compiler reordering/caching across the wait/wake paths. Acked-by: Pankaj Gupta Signed-off-by: Li Chen Signed-off-by: Michael S. Tsirkin Message-ID: <20260630092338.2094628-8-me@linux.beauty> Stable-dep-of: e57140944b5a ("nvdimm: virtio_pmem: refcount requests for token lifetime") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/nvdimm/nd_virtio.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) --- a/drivers/nvdimm/nd_virtio.c +++ b/drivers/nvdimm/nd_virtio.c @@ -24,9 +24,9 @@ static void virtio_pmem_wake_one_waiter( req_buf = list_first_entry(&vpmem->req_list, struct virtio_pmem_request, list); - req_buf->wq_buf_avail = true; + list_del_init(&req_buf->list); + WRITE_ONCE(req_buf->wq_buf_avail, true); wake_up(&req_buf->wq_buf); - list_del(&req_buf->list); } /* The interrupt handler */ @@ -40,7 +40,7 @@ void virtio_pmem_host_ack(struct virtque spin_lock_irqsave(&vpmem->pmem_lock, flags); while ((req_data = virtqueue_get_buf(vq, &len)) != NULL) { virtio_pmem_wake_one_waiter(vpmem); - req_data->done = true; + WRITE_ONCE(req_data->done, true); wake_up(&req_data->host_acked); } spin_unlock_irqrestore(&vpmem->pmem_lock, flags); @@ -72,7 +72,7 @@ static int virtio_pmem_flush(struct nd_r if (!req_data) return -ENOMEM; - req_data->done = false; + WRITE_ONCE(req_data->done, false); init_waitqueue_head(&req_data->host_acked); init_waitqueue_head(&req_data->wq_buf); INIT_LIST_HEAD(&req_data->list); @@ -93,12 +93,12 @@ static int virtio_pmem_flush(struct nd_r GFP_ATOMIC)) == -ENOSPC) { dev_info(&vdev->dev, "failed to send command to virtio pmem device, no free slots in the virtqueue\n"); - req_data->wq_buf_avail = false; + WRITE_ONCE(req_data->wq_buf_avail, false); list_add_tail(&req_data->list, &vpmem->req_list); spin_unlock_irqrestore(&vpmem->pmem_lock, flags); /* A host response results in "host_ack" getting called */ - wait_event(req_data->wq_buf, req_data->wq_buf_avail); + 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); @@ -112,7 +112,7 @@ static int virtio_pmem_flush(struct nd_r err = -EIO; } else { /* A host response results in "host_ack" getting called */ - wait_event(req_data->host_acked, req_data->done); + wait_event(req_data->host_acked, READ_ONCE(req_data->done)); err = le32_to_cpu(req_data->resp.ret); }