FAILED: patch "[PATCH] nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-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 <[email protected]>.

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-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 4606467a75cfc16721937272ed29462a750b60c8
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026071925-skimmer-retainer-3785@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 4606467a75cfc16721937272ed29462a750b60c8 Mon Sep 17 00:00:00 2001
From: Shivam Kumar <[email protected]>
Date: Wed, 18 Mar 2026 18:56:58 -0400
Subject: [PATCH] nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in
digest error path

In nvmet_tcp_try_recv_ddgst(), when a data digest mismatch is detected, nvmet_req_uninit() is called unconditionally. However, if the command arrived via the nvmet_tcp_handle_req_failure() path, nvmet_req_init() had returned false and percpu_ref_tryget_live() was never executed. The unconditional percpu_ref_put() inside nvmet_req_uninit() then causes a refcount underflow, leading to a WARNING in percpu_ref_switch_to_atomic_rcu, a use-after-free diagnostic, and eventually a permanent workqueue deadlock.

Check cmd->flags & NVMET_TCP_F_INIT_FAILED before calling nvmet_req_uninit(), matching the existing pattern in nvmet_tcp_execute_request().

index 4b8b02341ddc..69e971b179ae 100644
@@ -1310,7 +1310,8 @@ static int nvmet_tcp_try_recv_ddgst(struct nvmet_tcp_queue *queue)
 			queue->idx, cmd->req.cmd->common.command_id,
 			queue->pdu.cmd.hdr.type, le32_to_cpu(cmd->recv_ddgst),
 			le32_to_cpu(cmd->exp_ddgst));
-		nvmet_req_uninit(&cmd->req);
+		if (!(cmd->flags & NVMET_TCP_F_INIT_FAILED))
+			nvmet_req_uninit(&cmd->req);
 		nvmet_tcp_free_cmd_buffers(cmd);
 		nvmet_tcp_fatal_error(queue);
 		ret = -EPROTO;

commit 4606467a75cfc16721937272ed29462a750b60c8 upstream.

In nvmet_tcp_try_recv_ddgst(), when a data digest mismatch is detected, nvmet_req_uninit() is called unconditionally. However, if the command arrived via the nvmet_tcp_handle_req_failure() path, nvmet_req_init() had returned false and percpu_ref_tryget_live() was never executed. The unconditional percpu_ref_put() inside nvmet_req_uninit() then causes a refcount underflow, leading to a WARNING in percpu_ref_switch_to_atomic_rcu, a use-after-free diagnostic, and eventually a permanent workqueue deadlock.

Check cmd->flags & NVMET_TCP_F_INIT_FAILED before calling nvmet_req_uninit(), matching the existing pattern in nvmet_tcp_execute_request().

---
 drivers/nvme/target/tcp.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

index edcc0662c..ba5817006 100644
@@ -1200,7 +1200,9 @@ static int nvmet_tcp_try_recv_ddgst(struct nvmet_tcp_queue *queue)
 			queue->idx, cmd->req.cmd->common.command_id,
 			queue->pdu.cmd.hdr.type, le32_to_cpu(cmd->recv_ddgst),
 			le32_to_cpu(cmd->exp_ddgst));
-		nvmet_tcp_finish_cmd(cmd);
+		if (!(cmd->flags & NVMET_TCP_F_INIT_FAILED))
+			nvmet_req_uninit(&cmd->req);
+		nvmet_tcp_free_cmd_buffers(cmd);
 		nvmet_tcp_fatal_error(queue);
 		ret = -EPROTO;
 		goto out;

2.50.1 (Apple Git-155)

Queued for 5.10, thanks.

Thanks,
Sasha