From da2ce9b50f49e5898c833ba58662feaed7c6e786 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Tue, 28 Jul 2026 04:03:31 +0800 Subject: [PATCH] nvmet-tcp: Do not WARN on remotely-controlled oversized SGL allocations ANBZ: #45305 nvmet-tcp: Do not WARN on remotely-controlled oversized SGL allocations commit 737a3b535247226f6e1a7988fd9d6e63e7d6fc71 upstream. commit 8d01f0d0e96485e39ad89b859ef85e1dc3020465 stable. When fuzzing the nvme target code, I tripped a kernel warning in nvmet_tcp_map_data() because the length passed into the allocator is controlled by the remote initiator. A remote initiator that sends a command with an SGL claiming a huge number, can create a scatterlist and iovec allocation of over 1 million entries, which causes the backing kmalloc call to exceed MAX_PAGE_ORDER and then the page allocator will trip on a WARN_ON_ONCE_GFP() message: WARNING: mm/page_alloc.c:5280 __alloc_frozen_pages_noprof Workqueue: nvmet_tcp_wq nvmet_tcp_io_work ... sgl_alloc_order nvmet_tcp_map_data nvmet_tcp_try_recv_pdu As it's never good to trip a kernel warning remotely due to many systems having panic-on-warn enabled, let's silence it by just add GFP_NOWARN to the allocation flags. Assisted-by: gkh_clanker_2000 Cc: stable Signed-off-by: Greg Kroah-Hartman Signed-off-by: Keith Busch Signed-off-by: Greg Kroah-Hartman Fixes: CVE-2026-80788 Assisted-by: PatchPilot Signed-off-by: Guixin Liu --- drivers/nvme/target/tcp.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c index 84616567d5e9..6bc439166fc2 100644 --- a/drivers/nvme/target/tcp.c +++ b/drivers/nvme/target/tcp.c @@ -394,14 +394,15 @@ static int nvmet_tcp_map_data(struct nvmet_tcp_cmd *cmd) } cmd->req.transfer_len += len; - cmd->req.sg = sgl_alloc(len, GFP_KERNEL, &cmd->req.sg_cnt); + cmd->req.sg = sgl_alloc(len, GFP_KERNEL | __GFP_NOWARN, + &cmd->req.sg_cnt); if (!cmd->req.sg) return NVME_SC_INTERNAL; cmd->cur_sg = cmd->req.sg; if (nvmet_tcp_has_data_in(cmd)) { cmd->iov = kmalloc_array(cmd->req.sg_cnt, - sizeof(*cmd->iov), GFP_KERNEL); + sizeof(*cmd->iov), GFP_KERNEL | __GFP_NOWARN); if (!cmd->iov) goto err; } -- Gitee