From faebb7ba1ac65fa5810b640df02ce04e509fdc11 Mon Sep 17 00:00:00 2001 From: Lizhi Hou Date: Thu, 16 Jul 2026 08:13:05 -0700 Subject: [PATCH] accel/amdxdna: Fix use-after-free of mm_struct in job scheduler amdxdna_cmd_submit() stores current->mm in job->mm without holding any reference. aie2_sched_job_run() later access job->mm from the DRM scheduler worker thread. With only a raw pointer and no structural reference, the mm_struct can be freed before the scheduler runs the job. Fix this by calling mmgrab() to hold a structural mm_count reference for the lifetime of the job, paired with mmdrop() in every cleanup path. Fixes: aac243092b70 ("accel/amdxdna: Add command execution") Reviewed-by: Max Zhen Signed-off-by: Lizhi Hou Link: https://patch.msgid.link/20260716151305.1595780-1-lizhi.hou@amd.com --- drivers/accel/amdxdna/amdxdna_ctx.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/accel/amdxdna/amdxdna_ctx.c b/drivers/accel/amdxdna/amdxdna_ctx.c index bdbd3db12a6c..31a414c3f0d9 100644 --- a/drivers/accel/amdxdna/amdxdna_ctx.c +++ b/drivers/accel/amdxdna/amdxdna_ctx.c @@ -577,6 +577,7 @@ void amdxdna_sched_job_cleanup(struct amdxdna_sched_job *job) amdxdna_arg_bos_put(job); amdxdna_gem_put_obj(job->cmd_bo); dma_fence_put(job->fence); + mmdrop(job->mm); } int amdxdna_cmd_submit(struct amdxdna_client *client, @@ -642,6 +643,7 @@ int amdxdna_cmd_submit(struct amdxdna_client *client, job->hwctx = hwctx; job->mm = current->mm; + mmgrab(job->mm); job->fence = amdxdna_fence_create(hwctx); if (!job->fence) { @@ -676,6 +678,8 @@ put_bos: cmd_put: amdxdna_gem_put_obj(job->cmd_bo); free_job: + if (job->mm) + mmdrop(job->mm); kfree(job); return ret; } -- 2.47.3