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 2A2C434EF15; Fri, 4 Sep 2026 05:27:24 +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=1788499645; cv=none; b=PS122tMedcyLxRRh7JSV4gBTK2Zoh8brAxahY1T7WKthncM3i9vl7Ax0Wif355s4HBc7tvOd8eNjQ3Y45wwOwRMH1xSmdWtU83ZRzAKrJVqUz/gVLiSx8F4lByiqXiKA5OLzeiFxKBZ8898NFH7O0vVuVfYnbWSKUKkdaacyYKI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788499645; c=relaxed/simple; bh=yyP3J+lIgoTvCaFjg9r25bIvO3xWeEdqeeYieOCiLqs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=m87zf6B4ahXi5/xZ6RxGAwj3o0velHQBzC16HYNLYjrYblNl4+bmjniEp9guYep+78c28/z8zztaxxY4a0xnmHfpvH66BLxgwe85PHtxPWeD5kvqJ0UmH1JFOoI8UZD0eoAGxupSWDvdvMk0k8rkug9Dkt+t45RAtyqQj/QWKrs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=VnBqh6zF; 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="VnBqh6zF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 842C71F00A3D; Fri, 4 Sep 2026 05:27:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788499644; bh=sp1Syva0Q8roKfIm4aLgGI8lPs3zCyblOMEXpl6V20k=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=VnBqh6zFO7F9ZNNf8gAVTPmXorJQzfcPqRuF/SLMj+D1nFGGA62B0kyNpSwEazylk 0U7uwlECl7lCBbLgxcaImN1QeLpUZHRYFH9HFMpHg1dMRpXZDh1UNFlH//tCxnYpup XJthjeoYrn0dvok+cUXFIPLU30ESqejSIebEx18c= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yehyeong Lee , Keith Busch Subject: [PATCH 7.2 488/713] nvme: zero the discard fallback page Date: Fri, 4 Sep 2026 06:57:36 +0200 Message-ID: <20260904045814.766736474@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045803.810145556@linuxfoundation.org> References: <20260904045803.810145556@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: Yehyeong Lee commit bededeaaeff404978a5a8e2a605a6c3017cddd3e upstream. nvme_setup_discard() always maps sizeof(struct nvme_dsm_range) * NVME_DSM_MAX_RANGES = 4096 bytes as the DSM payload however many ranges the command declares, because some devices ignore the 'Number of Ranges' field - the Fixes: commit records two that read past the declared ranges. A single-range discard fills only the first 16 bytes. Normally the buffer comes from kzalloc() and the other 4080 bytes are zero. When that allocation fails the code falls back to the per-controller ctrl->discard_page, which nvme_init_ctrl() obtains with alloc_page(GFP_KERNEL) and nothing ever zeroes, so those 4080 bytes are whatever the page last held and are handed to the controller. Reaching it requires the kzalloc(GFP_ATOMIC | __GFP_NOWARN) to fail, that is memory pressure; it is not remotely triggerable. Failing the allocation under KMSAN reproduces it, with the leaked tail full of vmemmap struct page pointers. The extent in the report is a partial transfer of the payload, not the whole 4096 bytes; the 16-byte boundary in it is the one declared range: [ 11.991601] BUG: KMSAN: uninit-value in dma_map_phys+0x14c8/0x1900 [ 11.991969] dma_map_phys+0x14c8/0x1900 [ 11.992220] dma_map_page_attrs+0xcf/0x130 [ 11.992485] e1000_xmit_frame+0x4099/0x6d10 [ 11.992768] dev_hard_start_xmit+0x22f/0xa80 [ 11.993068] sch_direct_xmit+0x35c/0xcb0 [ 11.993315] __dev_queue_xmit+0x1ee5/0x5eb0 [ 11.993608] ip_finish_output2+0x1903/0x1c30 [ 11.993881] ip_finish_output+0x288/0x870 [ 11.994125] ip_output+0x15e/0x400 [ 11.994365] __ip_queue_xmit+0x1e85/0x1fb0 [ 11.994639] ip_queue_xmit+0x60/0x80 [ 11.994899] __tcp_transmit_skb+0x4e71/0x5fa0 [ 11.995210] tcp_write_xmit+0x3a36/0x9160 [ 11.995533] __tcp_push_pending_frames+0xc5/0x3c0 [ 11.995854] tcp_push+0x7dc/0x840 [ 11.996076] tcp_sendmsg_locked+0x766c/0x8400 [ 11.996371] tcp_sendmsg+0x4b/0x90 [ 11.996572] inet_sendmsg+0x134/0x2a0 [ 11.996823] __sock_sendmsg+0x265/0x360 [ 11.997076] sock_sendmsg+0x100/0x1e0 [ 11.997293] nvme_tcp_try_send+0x196f/0x6370 [ 11.997605] nvme_tcp_queue_rq+0x1d54/0x20b0 [ 11.997882] blk_mq_dispatch_rq_list+0x5ee/0x2e50 [ 11.998175] __blk_mq_sched_dispatch_requests+0x16dc/0x24a0 [ 11.998539] blk_mq_sched_dispatch_requests+0x11b/0x2c0 [ 11.998865] blk_mq_run_work_fn+0x13b/0x280 [ 11.999146] process_scheduled_works+0x966/0x1ad0 [ 11.999465] worker_thread+0xe44/0x1480 [ 11.999709] kthread+0x53b/0x600 [ 11.999927] ret_from_fork+0x29f/0x7c0 [ 12.000191] ret_from_fork_asm+0x1a/0x30 [ 12.000460] [ 12.000558] Uninit was created at: [ 12.000788] __alloc_frozen_pages_noprof+0x8bf/0xd30 [ 12.001096] alloc_pages_mpol+0x1d0/0x5f0 [ 12.001326] alloc_pages_noprof+0x102/0x290 [ 12.001627] nvme_init_ctrl+0x5a3/0x9f0 [ 12.001891] nvme_tcp_create_ctrl+0xd75/0x19b0 [ 12.002170] nvmf_dev_write+0x4c68/0x4fd0 [ 12.002426] vfs_write+0x587/0x1a10 [ 12.002636] __x64_sys_write+0x207/0x4f0 [ 12.002874] x64_sys_call+0x2ff0/0x3ea0 [ 12.003123] do_syscall_64+0x147/0x3b0 [ 12.003400] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 12.003680] [ 12.003777] Bytes 16-2843 of 2844 are uninitialized [ 12.004068] Memory access of size 2844 starts at ffff888109f82000 [ 12.004412] [ 12.004530] CPU: 0 UID: 0 PID: 101 Comm: kworker/0:1H Not tainted 7.2.0-rc5-NVMECTL-gf5098b6bae76 #1 PREEMPT(lazy) [ 12.005127] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 12.005762] Workqueue: kblockd blk_mq_run_work_fn [ 12.006073] ===================================================== Allocate the page with __GFP_ZERO. The single allocation site covers every use of it: bytes no discard has written stay zero, and bytes one did write hold that controller's own range list, which it has already been sent. Fixes: 530436c45ef2 ("nvme: Discard workaround for non-conformant devices") Cc: stable@vger.kernel.org Signed-off-by: Yehyeong Lee Signed-off-by: Keith Busch Signed-off-by: Greg Kroah-Hartman --- drivers/nvme/host/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -5195,7 +5195,7 @@ int nvme_init_ctrl(struct nvme_ctrl *ctr BUILD_BUG_ON(NVME_DSM_MAX_RANGES * sizeof(struct nvme_dsm_range) > PAGE_SIZE); - ctrl->discard_page = alloc_page(GFP_KERNEL); + ctrl->discard_page = alloc_page(GFP_KERNEL | __GFP_ZERO); if (!ctrl->discard_page) { ret = -ENOMEM; goto out;