FAILED: patch "[PATCH] accel/amdxdna: reject user command submission without a" failed to apply to 6.18-stable tree

The patch below does not apply to the 6.18-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-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x 261c1fe3327ad24508f54552c6366e3e4db82c15
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026072039-spouse-automatic-c20e@gregkh' --subject-prefix 'PATCH 6.18.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

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

From 261c1fe3327ad24508f54552c6366e3e4db82c15 Mon Sep 17 00:00:00 2001
From: Doruk Tan Ozturk <[email protected]>
Date: Mon, 13 Jul 2026 19:30:28 +0200
Subject: [PATCH] accel/amdxdna: reject user command submission without a
command BO

amdxdna_drm_submit_execbuf() passes the user-supplied command BO handle straight into amdxdna_cmd_submit() with drv_cmd == NULL. When the handle is AMDXDNA_INVALID_BO_HANDLE (0), the block that fetches job->cmd_bo is skipped, leaving it NULL, and no check rejects it on the user path (the !job->cmd_bo guard lives inside the != INVALID branch).

The job is then armed and pushed to the DRM scheduler. aie2_sched_job_run() takes the drv_cmd == NULL path and calls amdxdna_cmd_set_state(job->cmd_bo) -> amdxdna_gem_vmap(NULL) -> to_gobj(NULL)->dev, a NULL pointer dereference in the drm_sched worker. A process with access to the accel node on a system with a probed AMD NPU can trigger a kernel oops with a single AMDXDNA_EXEC_CMD ioctl (cmd_handles = 0).

Only internal driver commands (SYNC_DEBUG_BO / ATTACH_DEBUG_BO) legitimately pass AMDXDNA_INVALID_BO_HANDLE, and they always set drv_cmd. Reject the invalid handle for user submissions (drv_cmd == NULL) at the submit choke point so every user path is covered.

Found by 0sec automated security-research tooling (https://0sec.ai).

index 8f8df9d04ec5..a5c8c2c4de6d 100644
@@ -603,6 +603,16 @@ int amdxdna_cmd_submit(struct amdxdna_client *client,
 			ret = -EINVAL;
 			goto free_job;
 		}
+	} else if (!drv_cmd) {
+		/*
+		 * Only internal driver commands (drv_cmd != NULL) may omit a
+		 * command BO. A user command submission with the invalid handle
+		 * would leave job->cmd_bo NULL and later fault when the scheduler
+		 * dereferences it in amdxdna_cmd_set_state().
+		 */
+		XDNA_DBG(xdna, "Command BO handle required for user submission");
+		ret = -EINVAL;
+		goto free_job;
 	}
 
 	ret = amdxdna_arg_bos_lookup(client, job, arg_bo_hdls, arg_bo_cnt);

Hi Greg,

I checked both AMD XDNA failures on linux-6.18.y; neither needs a replacement backport:

- 261c1fe3327ad24508f54552c6366e3e4db82c15 depends on the later debug-buffer/drv_cmd refactor. Resolving its conflict would change 6.18’s existing command-less aie2_sync_bo path.
- 38953513d7313992676d4136cd425cdb70c6278e fixes AIE4 VF support, which is absent from 6.18; the supported devices there all have a cmd_submit op.

Please drop both from the 6.18 queue; no replacement backports are needed.

Thanks,
Doruk